Food Engineering
Mohammad Reza Salahi; Seyed Mohammad Ali Razavi; Mohebbat Mohebbi
Abstract
Introduction Emulsion-filled gel is a sort of gel system that traps oil droplets as a filler and contains a wide range of semi-solid to solid food products. It can also be utilized as a dual system to distribute and control the release of both lipophilic and hydrophilic bioactive and micronutrient ...
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Introduction Emulsion-filled gel is a sort of gel system that traps oil droplets as a filler and contains a wide range of semi-solid to solid food products. It can also be utilized as a dual system to distribute and control the release of both lipophilic and hydrophilic bioactive and micronutrient substances. The main polymers involved in gel formation in food products are proteins and polysaccharides. Using molecular interactions between biopolymers, a wide range of rheological and physicochemical properties of gels can be methodically created. As a result, the interaction between proteins and polysaccharides has received a lot of attention in order to generate novel products. Because of their functional qualities and high nutritional value, whey proteins are frequently used in the food industry. As a result, mixed gels based on whey protein have gained a lot of attention. k-Carrageenan is commonly utilized in the food industry as a gelling and firming agent. Because k-Carrageenan, like whey protein isolate, can form a gel independently, its interaction with whey protein isolate in emulsion gel systems appears appealing. Therefore, in this study, the effect of k-Carrageenan gum (0.0, 0.1, 0.3, 0.5, and 0.7%) on the textural (uniaxial compression test), rheological (steady shear, strain sweep, and frequency sweep tests), and water holding capacity of cold-set emulsion-filled gel based on whey protein isolate was investigated. Materials and Methods Whey protein isolate (WPI) (98.9% protein, dry basis) was given as a gift by Agropur Ingredients Co. (Le Sueur, Minnesota, USA). -Carrageenan and CaCl2 ( : 147.01 gr/mol) were purchased from Sigma Aldrich Co. (USA) and Merck Co. (Darmstadt, Germany), respectively. Sunflower oil was supplied from local supermarket. Stock dispersions of WPI and -Carrageenan were prepared by dissolving sufficient amounts of their powders in deionized water. To prepare uniform oil in water emulsion, sunflower oil was added to the WPI dispersion and the obtained mixture homogenized first using a laboratory rotor-stator homogenizer (15000 rpm, 3 min), then by an ultrasonic homogenizer (20 kHz, 5 min). The prepared emulsion and -Carrageenan dispersions were poured into Schott bottles and heated in a water bath (90 °C, 40 min). WPI emulsion and AG dispersion were mixed in a cylindrical container on a stirring plate at a speed of 600 rpm for 6-8 min to obtain a homogeneous mixture. After decreasing the temperature to 60 °C for the ion-induced gelation, the mixtures were charged with CaCl2 (10 mM). The prepared samples were incubated in a refrigerator overnight to stabilize the 3D network. The final mixed EFG samples contained 5.5% WPI, 20% oil, and 0, 0.1, 0.3, 0.5, and 0.7% (w/w) of k-carrageenan. The tests performed on emulsion-filled gel samples were: 1) steady shear (0.01-10 s-1), 2) strain sweep (strain: 0.1-1000%, frequency: 1 Hz), 3) frequency sweep (frequency: 0.1-100 Hz, strain: 0.5%), 4) uniaxial compression (target strain: 80%, deformation speed:1 mm/s), and 5) water holding capacity (by utilizing a microcentrifuge, 600×g for 10 min). Results and Discussion According to the results of steady shear test, all samples had a shear thinning behavior, and based on the power-law model, this behavior was intensified in the presence of k-Carrageenan; and with increasing the gum concentration from 0 to 0.7%, the consistency coefficient increased from 339.9 to 545.7 Pa.s. In the strain sweep test, with the increase in the gum concentration, the values of the elastic and viscous modulus in the linear region and the modulus at the crossover point increased, and tan dLVE decreased from 0.17 to 0.13, which indicated an increase in the strength of the emulsion gel network structure. Based on the frequency sweep test, with the increase in k-Carrageenan concentration, the parameters and , network strength and network expansion increased from 5311.8 Pa, 939.9 Pa, 1.5380 Pa.s1/z and 10.05 in the control sample to 25080 Pa, 3574.9 Pa, 16097.7 Pa.s1/z and 16.41 in the sample containing 0.7% k-Carrageenan, respectively. Moreover, the frequency dependency of elastic modulus decreased from 0.095 in the control sample to 0.050 in the 0.7% k-Carrageenan contained sample. According to the large deformation test, in general, in the composite emulsion-filled gels, the values of apparent modulus of elasticity and fracture stress were higher and fracture strain and fracture energy were lower than in the control sample. Also, the results showed that different k-Carrageenan concentrations had no significant effect on the water holding capacity. ConclusionThe obtained results showed that k-Carrageenan had considerable influence on the rheo-mechanical features of cold-set emulsion-filled gels based on whey protein which can add to the knowledge base for the production of new functional foods.
Food Biotechnology
Shohreh Nikkhah; Fakhri Shahidi; Mohebbat Mohebbi; Farideh Tabatabaei Yazdi
Abstract
IntroductionCucumber is an economically important crop, containing vitamins, minerals, antioxidants, and flavonoids. However, due to loss of weight and firmness, microbial contamination, mechanical damage, and yellowing, the storage duration of cucumber is limited to 3–5 days at room temperature. ...
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IntroductionCucumber is an economically important crop, containing vitamins, minerals, antioxidants, and flavonoids. However, due to loss of weight and firmness, microbial contamination, mechanical damage, and yellowing, the storage duration of cucumber is limited to 3–5 days at room temperature. Therefore, pretreatments are crucial for prolonging its shelf life. Chitosan is a cationic polysaccharide and can interact electrostatically with anionic, partially demethylated pectin. Besides, chitosan has inhibitory effects on fungal rot and prevents weight loss in fruits. Pectin can form excellent films. Because of increasing demand to reduce synthetic chemicals as antimicrobial agents, substances derived from plants, such as essential oils, can play a significant role in the future. Several essential oils and essential oil components have shown antimicrobial activity against spoilage and pathogenic microorganisms during fruit and vegetable storage. Essential oils of thyme and cinnamon contained phenolic groups have been found to be most consistently effective against microorganisms, however, essential oils are volatile and irritant. Therefore, forming an inclusion complex using b-cyclodextrin can improve solubility, control volatile, and induce off-flavors and unpleasant odor of the essential oils. The objectives of this study were to develop the microencapsulated thymol (thyme) and trans-cinnamaldehyde (cinnamon) essential oils to produce antimicrobial agents and subsequently evaluate the effectiveness of edible coating made of chitosan and pectin containing microencapsulated trans-cinnamaldehyde or thymol essential oils to improve qualitative and quantitative characteristics and shelf life of cucumber.Materials and MethodsThe inclusion complexes of trans-cinnamaldehyde and thymol in beta-cyclodextrin (CD) were prepared separately by freeze-drying. Each essential oil was dispersed in 1000 ml of beta-cyclodextrin aqueous solution (16 mmol/L, 18.15 g) in molecular ratio 1:1 (2.4 gr thymol, 2.11 gr trans-cinnamaldehyde) and mixed in a laboratory stirrer for 24 hour at room temperature , then frozen (-70 ºc) and freeze-dried (<20Pa, 48 h). Lyophilized samples were stored inside a freezer (-20 ºc) until further use. Cucumbers cv. Nagene with uniform size, appearance, ripeness and without mechanical damage or fungal contamination were selected. Then They were then sanitized by immersion in chlorine solution (150 mg/kg) for 1 min and air dried. Edible coatings were prepared as three immersion solutions of chitosan, pectin, and calcium chloride (CaCl2). The fruits were coated with pectin (1%) and chitosan (0-0.5%-1%) containing beta-cyclodextrin microencapsulated trans-Cinnamaldehyde or thymol each (0-0.25%-0.5%). After coating by chitosan, the fruits were immersed in 1% Calcium chloride solution to induce crosslinking reaction. After dipping step, fruits dried for 8 minutes at room temperature to remove the excess solution attached to the surface .Uncoated fruits served as control. Then fruits were preserved in cold storage (temperature: 10ºc; relative humidity: 90-95%) for 15 days. chemical (total soluble solids, titratable acidity) and physical (total color difference, Hardness, and weight loss) Characterization of fruits were measured immediately after harvest and after 5, 10 and15 days. Microbial tests (total count, mold, and yeast) were done at the end of preservation time. Analytical data were subjected to analysis of variance and factorial adopted completely randomized design and a Duncan comparison test was used. Results and DiscussionThe results showed that weight loss, total soluble solids, and the total color difference increased and hardness and titratable acidity decreased gradually in all samples during cold storage (<0.05). Chitosan and essential oils slowed down this rising or decreasing trends. Interactive effects of chitosan, essential oil type, essential oil concentration, and storage time had positive effects on these quality attributes. The fruits coated with the highest concentration of chitosan (1%) and thymol (0.5%) essential oils showed the least weight loss, loss of hardness, and color change throughout 15 days of storage. Besides thymol in comparison with trans-Cinnamaldehyde was more efficient to prevent yeasts and molds on the surface of cucumber. By increasing chitosan and essential oil amounts, the ability of inhibiting microbial growth by coating is enhanced. ConclusionThe results of chemical, physical and microbial tests, showed that multi-layer coating solution containing chitosan 1% with thymol 0.5% was effective in extending the shelf life of cucumber. The combined usage of microencapsulated thymol essential oil and chitosan-based coating on cucumber could be considered a healthy and effective treatment that reduces microbial spoilage and preserves quality and color characteristics in cucumber and represents an innovative method for commercial application. Therefore, this coating can be used as an alternative to chemical fungicides to prevent fungal rot of cucumber and other fruits, however, it is suggested that more studies should be done in this field.
Food Technology
Parisa Parsa; Mostafa Mazaheri Tehrani; Mohebbat Mohebbi
Abstract
Introduction Bran-enriched bread is a source of dietary fibers and other nutritional compounds; However, wheat bran also contains phytic acid, asparagine, a high ratio of insoluble to soluble fiber, insoluble arabinoxylans, and glutathione that cause nutritional and technological problems in the ...
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Introduction Bran-enriched bread is a source of dietary fibers and other nutritional compounds; However, wheat bran also contains phytic acid, asparagine, a high ratio of insoluble to soluble fiber, insoluble arabinoxylans, and glutathione that cause nutritional and technological problems in the product. Therefore, to produce bran-enriched bread, it is necessary to use pre-processed wheat bran. Despite the modifications made in wheat bran to improve its nutritional and functional properties, wheat bran-rich cereal products have a dark color, rough texture, and small loaf volume. To improve the quality of bran-enriched bread, common additives in the bakery industry such as enzymes, alcoholic sugars, emulsifiers can be used. Xylanase is one of the important classes of hemicellulase enzymes that delays the aggregation of amylose chains, and consequently, bread staling. Moreover, the xylanase enzyme increases the loaf volume by converting water-insoluble arabinoxylans into soluble ones. SSL emulsifier can interact with gliadin protein and prevent its participation in crosslinking bonds, which softens the bread crumbs. Polyols can reduce water activity and improve the softness of bread. Sorbitol is commonly used in starch-based foods to improve their quality by modifying starch gelatinization and retrogradation. So far, no article has been presented on the simultaneous effect of enzyme, alcoholic sugar, and emulsifier improvers on bread enriched with processed wheat bran. In addition, the amount and composition of improvers used in combination with each other can cause various effects on different properties of bread. This study aims to improve the technological, physicochemical, and finally stalling of optimal bread enriched with 15% of pre-processed wheat bran while benefiting from the nutritional properties of wheat bran. Materials and Methods In this study, the effect of sodium stearoyl-2-lactylate emulsifier (0-0.8%), xylanase enzyme (0-0.05%), and sorbitol sugar alcohol (0-6%) as improving agents on The physicochemical and technological parameters of bread enriched with 15% pre-processed wheat bran were investigated based on the response surface method in the form of a rotatable central composite design. After that, design-expert software determined the optimum percentage of improvers to achieve the minimum amount of firmness and cohesiveness of bread and the maximum amount of specific volume, moisture of bread crumbs, lightness of bread crust, and solidity of bread pore structure. Finally, optimal and control samples were compared using the Differential Scanning Calorimetry and Scanning Electron Microscopic experiments. Results and Discussion The experiments showed the bread's firmness under the influence of SSL emulsifier and sorbitol alcoholic sugar and chewiness, by adding SSL emulsifier and xylanase enzyme decreased significantly. All three improvers caused a significant increase in the specific volume of bread. The pore characteristics of bread crumbs, such as solidity and circularity, were significantly improved by adding an SSL emulsifier, and roundness was considerably enhanced by adding sorbitol alcohol. The brightness of bread crust was also increased significantly by the SSL emulsifier and xylanase enzyme. In addition, the Xylanase enzyme improved the moisture content of bread by substantially increasing the moisture content of bread crumbs, and alcoholic sugar and SSL emulsifier with a significant reduction in crust moisture. Moreover, the chewiness of bread on the first day after baking, specific volume, moisture of bread crust on the third day after baking, and the solidity of bread crumbs were significantly improved due to the interaction of SSL emulsifier and sorbitol alcohol. Also, the interaction of the xylanase enzyme and SSL emulsifier improved the specific volume, moisture of the bread crumbs on the first day after baking, the lightness of the bread crust, the pore area fraction, and the circularity of the bread crumbs. Finally, the optimal formula was obtained, including 0.563% of SSL emulsifier, 0.040% of xylanase enzyme, and 2.356% of alcoholic sugar sorbitol. The results showed a significant decrease in enthalpy and an increase in the initial gelatinization temperature in the optimal sample compared to the control ones. Also, a weaker gluten network, more swelling, and amounts of starch granules in the microstructure of sample bread were observed. Conclusion In conclusion, SSL emulsifier by interaction with amylose and amylopectin in starch granules, sorbitol alcohol via interacting with water molecules surrounding starch chains or by bonding between starch chains in amorous regions, and xylanase enzyme through reducing rate of crystallization can reduce the gelatinization of starch granules, enthalpy, and finally the retrogradation process of amylopectin and stalling rate of bread with their synergic effects. In this research, we formulate the wheat bran-enriched bread that not only benefits from the nutritional features of wheat bran but also preserves the quality characteristics of bread.
Food Engineering
Mohammad Khalilian-Movahhed; Mohebbat Mohebbi; Charlotte Sinding
Abstract
IntroductionEfforts have always been made to protect valuable compounds of medicine, food and aromatics materials that are highly sensitive to environmental conditions by the encapsulation method. encapsulation of flavors, in addition to its protection, allows the aromatic substance to be released in ...
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IntroductionEfforts have always been made to protect valuable compounds of medicine, food and aromatics materials that are highly sensitive to environmental conditions by the encapsulation method. encapsulation of flavors, in addition to its protection, allows the aromatic substance to be released in a long time, and the time and place of its release can be controlled. To design these protection systems requires detailed information on encapsulation and release methods, the nature of walls and aromatic materials (Gunning et al.,1999). For encapsulation of sensitive compounds such as lipophilic materials, it is necessary to produce an emulsion of the desired substance in wall materials such as proteins, polysaccharides or a mixture of them. The important factors in encapsulation are the molecular weight, chemical properties and polarity of the core materials, the properties of the materials of the walls, and finally, the methods used to produce microcapsules. (Jafari et al., 2008).The aim of this study was to produce and evaluate the properties of two and six layer multilayer microcapsules containing limonene using soy protein isolate and starch modified by spray drying. The release of encapsulated limonene was investigated under artificial oral conditions under different stress conditions. The results of this study can be used to predict the release rate of the encapsulated flavors and their release conditions.Materials and MethodsSolution preparation: The solution of SPI (0-3%) was prepared by methods of Huang et al. (2012). The OSA starch stock solution (0-2%) was prepared by methods of Nilsson and Bergens (2007).Emulsion’s preparation: the primary emulsion of the optimum SPI and secondary emulsion of optimum OSA starch concentration prepared by the method of Noshad et al (2015).Microcapsule production: To prepare the Microcapsules, a laboratory spray dryer was used. 180±5 ᵒC, inlet air temperature, 25 (ml/min) feed rate, and 90±10 ᵒC outlet air temperature were used. Six layer microcapsules was also prepared in the same conditions (Ansarifar et al., 2017)The micro structure, morphology and release of limonene were evaluated and finally by Zero order, First order, Higuchi, and Korsemeyer- peppas models were used to the fitting of experimental data.Limonene release: To investigate the release of the encapsulated limonene, the release of these microcapsules (two and six layer) at 37 ° C and pH = 6.8, as well as frequent chewing (0, 50 and 100 rpm) were examined. For the apply of shear stress, an oral simulator was designed and developed by the Department of Food Science and Technology of Ferdowsi University of Mashhad was used. Results and DiscusionThe results of particle size changes of the initial emulsion formed with different levels of soy protein isolate showed that the particle size decreased with increasing the concentration of this protein to 1.5% and then it was increased. The results of zeta potential showed that with increasing the concentration of soy protein isolate to 1.5%, the zeta potential of the samples increased and with more than 1.5%, it did not have much effect on the zeta potential of the samples, which indicates that concentrate of 1.5% soy protein isolate has a good ability to cover surface of limonene particles. Similarly, 1.2% of OSA starch was determined for the secondary layer.SEM images of the microcapsules showed that in the two-layer wall microcapsules have cavities, cracks and shrinkage. In the starting of drying, the rate of moisture lost is high and on the other hand, the wall is not strong enough to withstand the stresses caused by the exit of moisture from the walls, so the microcapsule has cavities. In six-layer microcapsules, a smooth, non-cracked surface was observed, which can be attributed to the wall strength due to the increase in the number of layers. Fourier transform infrared spectroscopic (FTIR) test showed that the outer surface of the microcapsules was covered by OSA starch in two and six layer microcapsules.The release profile of encapsulated limonene showed that the release rate in two layer samples was faster than six layer samples. Also, with increasing shear rate, the amount of release increased. The results of experimental models fitting showed that the first-order model had the best description for releasing limonene from two- and six-layer samples in different conditions. Calculation of diffusion coefficient showed that six-layer microcapsules have a lower diffusion coefficient than two-layer microcapsules, which leads to a decrease in the release rate of limonene.Conclusion The results of this study showed that the layer-by-layer method could be used to produce limonene microcapsules. Soy protein isolate and modified starch can cover limonene droplets well. SEM images showed that the structure of six-layer microcapsules is free of cracks and cavities and has a more uniform surface than two-layer microcapsules. To investigate the mechanism of limonene release from two- and six-layer microcapsules, different kinetic models were used to fit the experimental release data. The results showed that the release of these microcapsules occurred based on the diffusion mechanism and Fick's law, which is the main mechanism of mass transfer in the release process. Also, the results showed that the six-layer microcapsules had a lower diffusion coefficient than the two-layer microcapsules and the release rate was lower in the two-layer microcapsule; This is due to the repetitive coating of soy protein isolate and modified starch around the microcapsules and the increase in wall thickness.
Food Engineering
Fateme Mousavi Baygi; Arash Koocheki; Behrooz Ghorani; Mohebbat Mohebbi
Abstract
Introduction Curcumin, as a natural polyphenolic nutraceutical has been shown many health-promoting effects, mainly associated with its chemical structure. In various studies, different properties of this compound, including anti-tumor and anti-cancer activity, reduction of blood and liver cholesterol ...
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Introduction Curcumin, as a natural polyphenolic nutraceutical has been shown many health-promoting effects, mainly associated with its chemical structure. In various studies, different properties of this compound, including anti-tumor and anti-cancer activity, reduction of blood and liver cholesterol levels, increase of immune function, prevention of cardiovascular diseases, prevention of damage to biological membranes against peroxidation and anti-inflammatory properties have been reported. Despite possessing a potential health benefits to humans, the susceptibility of this polyphenol towards environmental conditions and low chemical stability has restricted the direct usage of curcumin into aqueous-based food formulations. The encapsulation of curcumin in liposomes is a potentially effective way to protect them from degradation during passing the digestive system.Materials and MethodsCurcumin (powder, purity greater than 99%, 368.38 g/mol), lecithin, cholesterol (C3045-25G), pancreacin (extracted from porcine pancreas, P7545-25G), bile salts (B8756-10G) and calcium chloride (CaCl2) was obtained from Sigma Aldrich (USA). Consumable ethanol was purchased from Pars Ethanol Company (96%, Iran). Lipase enzyme (extracted from pig pancreas, L8070) and pepsin (activity 3500-3000 NFU/g, P8390) were obtained from Solarabio (China). Potassium chloride, dipotassium hydrogen phosphate (K2HPO4) and alpha-amylase enzyme with a purity of at least 99% were obtained from Merck, Germany, sodium chloride (NaCl), sodium bicarbonate (NaHCO3) and calcium chloride were obtained from Sigma. The effect of lecithin content (0.02- 0.08 g), lecithin cholesterol ratio (0.5- 4), curcumin level (1.5- 6mg) and ultrasound treatment time (1-5 minutes) on production of liposomes containing curcumin was evaluated. The particle size, particle size distribution, zeta potential and efficiency were determined by response surface methodology. Furthermore, physical nature, molecular structure, physical stability at 4ºC and 25ºC and release behavior of curcumin loaded-liposome in mouth, stomach and intestines were explored.Results and Discussion The results showed that all independent variables had a significant effect on liposome particle size and increasing the ratio of lecithin: cholesterol caused more uniform particle size. Lecithin was determined to be the only component affecting the zeta potential of liposome particles, and increasing the ultrasound time increased the efficiency of curcumin encapsulation in liposomes. The optimal point of liposome preparation conditions in the amount of 0.08 g lecithin, 4: 1 the ratio of lecithin: cholesterol, 4.16 mg curcumin and 5 minutes the ultrasound treatment was introduced by Design Expert software. In addition, curcumin was amorphous in optimal liposome spherical particles. Furthermore, the results of TEM showed that the liposomes are in the form of single-layer particles, spherical and without membrane rupture. This makes the bilayered nature of the vesicles clearly visible in this micrograph. The size of the particles obtained from this method was consistent with the data obtained from the dynamic light scattering method. From the results of infrared spectroscopy, it can be seen that curcumin is trapped in the liposome through hydrogen bonding in the double-layered vesicle of the liposome, the phenolic ring of curcumin with the phospholipid head group, as well as the hydrophobic interactions of the aromatic rings with the acyl phospholipid chains. Liposomes were more stable at refrigeration temperature. A very small amount of curcumin was released in the simulated oral phase, which is probably due to the short time and lack of specific enzymes to disrupt the phospholipid bilayers of the liposome. Although the pepsin enzyme is unable to penetrate the liposome membrane, acidic conditions change the angle of the head and tail groups of the lipids and lead to a change in the surface charge of the liposomes. The release of curcumin from liposome vesicles was greatly increased in the intestine. This sudden increase is due to the presence of bile salts as an emulsifying agent that can disrupt the phospholipid membrane and make the membrane more fluid. In addition, pancreatic lipase is adsorbed on the surface of lipids and then hydrolyzes the phospholipid into 2-acyl and 1-acyl lysophospholipids and free fatty acids. The release behavior of curcumin under gastrointestinal conditions was based on the Fick mechanism.
Food Technology
Amineh Avami; Mostafa Mazaheri Tehrani; Mohebbat Mohebbi; Fatemeh Pourhaji
Abstract
There is a challenge in producing a portion both compatible to ketogenic diet and sufficient satiety. This study investigated the possibility of producing sugar-free chocolate product using increasing total fat and protein. The ingredients were chosen such that they do not contain any source of starch ...
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There is a challenge in producing a portion both compatible to ketogenic diet and sufficient satiety. This study investigated the possibility of producing sugar-free chocolate product using increasing total fat and protein. The ingredients were chosen such that they do not contain any source of starch and sucrose. The cocoa powder was replaced with cocoa butter substitute (CBS) and sodium caseinate at different levels (0, 5 and 10%) along with constant amount of stevia ketogenic powder and soybean hull as sugar substitute. Results showed that cocoa powder substitution significantly (p< 0.05) led to an increase in moisture, water activity, fat and protein and a decrease in ash and carbohydrate amount, respectively. It was also observed that addition of sodium caseinate and CBS made the chocolate softer and to be easily melted (p< 0.05). Sensory analysis showed that samples with high protein and fat content got better scores in overall acceptance (p< 0.05). Also, principle component analysis showed that the first two components could explain about 81% of total variance. Finally, the best composition was determined by considering both TPA, DSC and sensory properties. This sample contained 5% sodium caseinate and 35% CBS. Moreover, total sugar content and calorie amount of this sample was 2.17% and 547.41 kcal, respectively. The peroxide value of optimized sample was 0.5 meq per kg immediately after production and it reached to 1.13 meq per kg after two months. Consuming 100 g of this chocolate can supply 27% of daily calorie of an adult person (assuming 2000 kcal per day for adults). Consuming this 100 g can also supply 17% and 40% of classic and atkins keto diet. These results showed that, the selected sample with 35% CBS and 5% sodium caseinate could be compatible to ketogenic diet but more clinical research should be done in future.
Alireza Abbasi; Arash Koocheki; Elnaz Milani; Mohebbat Mohebbi
Abstract
[1]Introduction: Breakfast cereal products are considered as an important meal for athletes and children. By changing eating habits and increasing the consumption of these products, choosing healthy and nutritious raw materials such as whole grains to produce breakfast cereals with great impact ...
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[1]Introduction: Breakfast cereal products are considered as an important meal for athletes and children. By changing eating habits and increasing the consumption of these products, choosing healthy and nutritious raw materials such as whole grains to produce breakfast cereals with great impact on people's health. Rice grain as a technologically important source of starch causes the expansion of extruded products. Since in the production of breakfast cereal and baby food products, exclusively starch with low amylose is used, this indicates the suitability of this source for productionof such products. During the dehusking process, about 14% of the rice is broken to smaller grains, which is commercially classified as a low-value product. The broken rice can be converted to rice flour and used as a raw material in various types of food products. To maintain consumer demand for healthy diets, it is necessary to use high-fiber flours because these types of products will be able to modify the process of decomposition of starch. Although the integration of fiber in products has technological challenges, but by using rice grain as an important source of starch, the technological properties, expansion index, volumetric density and texture (texture hardness and brittleness) can be accepted. At present, modified starch derivatives are widely used in the food industry due to the increase in the quality of the final product. In the production of ready-to-use products for flaking, puffing, a process called extrusion is used. In this process, the product suddenly loses its moisture and leads to the creation of a dense structure containing pores. In this study, the effect of extrusion cooking process parameters on the desired characteristics of flax and rice meal breakfast cereal product with desirable physicochemical and sensory properties was investigated. Materials and Methods: Extrusion: In this study, a parallel twin-screw extruder (Jinan Saxin, China) was applied, die diameter of 3 mm, and extrusion temperature of 140 ℃. Central composite statistical design was used to study the effect of feed moisture (12, 15 and 18%), screw speed (140, 170 and 200 rpm) and Flaxseed oil cake addition (10, 20 and 30%) on technological and functional properties expanded extrudates. The chemical composition of flax meal and rice flour was measured by standard AACC (2000) methods. The expansion ratio was calculated by dividing the mean diameter (mm) by the diameter of the extruder die (4 mm) (Brennan et al, 2008). Textural measurement: The hardness of the extruded breakfast cereals was measured using Texture Analyzer (TA plus Ametek, UK). The cylinder steel probe (2 mm diameter) was set to move at a speed of 1 mm/s The samples were punctured by the probe to a distance of 10 mm. Bowl life hardness: Breakfast cereal samples were immersed in whole milk (3% fat) at 5 ° C for 3 minutes, Then rinsing was performed for 10 seconds and finally the samples were tested similar to the tissue hardness test procedure before immersion by a tissue analyzer (Oliveira et al, 2017). The color parameters L* (lightness), a*(redness), b*(yellowness) values of the samples were determined by the Hunterlab machine (Reston VA, US) (Rhee et al, 2004). Water absorption index in terms of grams of bonded water was calculated. The WSI of the dry solids regained through the evaporation of the supernatant obtained from the water absorption test was calculated (Alam et al, 2019). Sensory evaluation was performed using a 9-point hedonic test. Response surface methodology was applied for experimental data using a commercial statistical package, Design Expert (version 7.0) for the generation of response surface plot and statistical analysis of the experimental data. Results and Discussion: One of the most important parameters in the evaluation of breakfast cereal products is the amount of bowl-life hardness, which in this study, the highest amount was obtained at the level of 30% of flaxseed meal, 18% moisture and the lowest amount of screw rotation speed. After immersing breakfast cereal in milk, by increasing the percentage of flax meal due to the harder flow path, moisture absorption decreases and thus prevents the expansion of the product and increases the density of the mass and the hardness of the tissue. Due to the formation of a layer of lipids and micelles on the surface of the product prevents moisture transfer and absorption, so tissue hardness decreases and bowl-life hardness time increases. In fact, the amount of moisture absorption is a good model that shows the potential of bowl hardness-life of the samples. It is also compact and dense, which increases the retention time of breakfast cereal texture. Moisture can also reduce the shear force as a plasticizer and increase the amount of moisture absorption of the product. While increasing the speed of screw rotation, the effect of shear force on starch dextrinization increases and reduces moisture absorption. Another important feature of breakfast cereals is the lightness index, the highest value of which was obtained at the speed of screw rotation, humidity and low flax meal level. In the study of sensory properties of products produced at meal levels less than 20%, moisture content less than 15% and screw speed of 200 rpm showed the highest overall acceptance.
Food Technology
Farinaz Saremnejad; Mohebbat Mohebbi; Arash Koocheki
Abstract
Introduction: Increasing diet-linked diseases and following that the consumers ongoing desire for healthier foods makes reduced-fat products of outstanding importance in the food industry. This study aims to reduce the fat content of sauces as a traditional condiment through the incorporation ...
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Introduction: Increasing diet-linked diseases and following that the consumers ongoing desire for healthier foods makes reduced-fat products of outstanding importance in the food industry. This study aims to reduce the fat content of sauces as a traditional condiment through the incorporation of air bubbles in the oil phase. Response surface methodology (RSM) was used for identifying the effect of aeration process variables on foam properties. However, the main challenge of reduced-fat foods is to ensure their acceptability. Recently fat taste has been introduced as a sixth basic taste. Fatty acids have been considered as the stimulus for this taste. So, linoleic acid as the stimulus for fat perception was added to the formulation to develop a product that tastes almost like full-fat versions but contains less fat. The advantages of aerated foods over conventional products are clear. Nonetheless, the determination of quality and sensory parameters during storage, marketing, and consuming is necessary. For this purpose, produced aerated sauces, along with commercial full- and reduced-fat sauces, were compared by measuring the acidity, pH, oxidative stability, and sensory properties. Materials and Methods: Required amounts of mono- and diglyceride (MDG) and oil were mixed. Then nonaqueous foams were generated by whipping the MDG-oil mixtures. In the optimization study, the effect of MDG concentrations (2, 6, and 10 wt. %), whipping speed (1100, 3250, and 5400 rpm) and time (5, 15, and 25 min) on foam properties (overrun and drainage) was analyzed using RSM. The foam obtained from the optimum process condition was used to produce an aerated reduced-fat sauce. Sauce preparation was performed according to a usual recipe with the difference that the fat content was replaced by nonaqueous foam. Furthermore, 3.00 mM of linoleic acid as a fat taste stimulus was added to the formulation. First, an aqueous phase containing ingredients was prepared. Then nonaqueous foam was progressively incorporated in the aqueous phase. For the purposes of comparison, aerated sauces (0 and 3.00 mM stimulus), along with commercial sauces (zero, low, and full-fat), were analyzed by measuring the pH, acidity, oxidative stability, and sensory properties. Results and Discussion: According to the results of the optimization study, the desired foam (overrun ≥ 60 %) achieved by oil containing 10 wt. % MDG at 3400 rpm for 10 min. Overrun increased progressively with MDG concentration but decreased slightly above 10 wt. % due to the difficulty of dispersing air bubbles in such a viscous gel. Considering the effect of whipping speed, and time, it was observed that mixtures reached their maximum volumes within 25 min. With a further increase in the whipping rate, the time required to achieve the maximum amount of foam was decreased. However, at high whipping speed (5400 rpm), foam volume decreased rapidly with time, and almost a lot of foam collapsed. The lowest and highest pH was related to zero and full-fat commercial sauces, respectively. There was no difference (p>0.05) between the pH of the control and the linoleic acid containing aerated, as well as low-fat sauces. Over time, as the pH decreases, the acidity of the aerated sauces increased and making the products with appropriate microbial stability. Due to the significant reduction of fat amount, oxidation of the aerated sauces was much slower than the full-fat one (p<0.05). Appearance, taste, and texture characteristics of aerated sauces provided a sensory profile similar to the full-fat sauce. The aerated sauce containing linoleic acid had higher sensory scores, indicating its general acceptance. Conclusions: In this study, nonaqueous foam as a new approach for fat replacement in emulsion-based foods such as sauces was practically applied. The optimum aeration process conditions were determined by the help of experimental design. Two types of aerated sauces were prepared based on the linoleic acid concentration, and their physicochemical and sensory characteristics were compared with commercial sauces. The acidity and pH of the sauces were in the standard range, and also their oxidative stability was acceptable during storage time. Generally, the aerated sauce containing linoleic acid had relatively similar sensory profiles to the full-fat sauce. Therefore, it seems that nonaqueous foam could be used successfully to develop reduced-fat alternative foods, which could also be meet the consumers' and marketing requirements.Materials and Methods: Required amounts of mono- and diglyceride (MDG) and oil were mixed. Then nonaqueous foams were obtained by whipping the MDG-oil mixtures. In the optimization study, the effect of MDG concentration (2, 6, and 10 wt. %), whipping speed (1100, 3250, and 5400 rpm) and time (5, 15, and 25 min) on foam properties (overrun and drainage) were analyzed using RSM. The foam obtained from the optimum process condition was used to produce an aerated reduced-fat sauce. Sauce preparation was performed according to a usual recipe with the difference that the fat content was replaced by nonaqueous foam. Furthermore, 3.00 mM of linoleic acid as a fat taste stimulus was added to the formulation. First, an aqueous phase containing ingredients was prepared. Then nonaqueous foam was progressively incorporated in the aqueous phase. For purposes of comparison, aerated sauces (0 and 3.00 mM stimulus), along with commercial sauces (zero and full-fat), were analyzed by measuring the pH, acidity, oxidative stability, and sensory properties. Results and Discussion: According to the results of the optimization study, the desired foam (overrun ≥ 60 %) achieved by oil containing 10 wt. % MDG at 3200 rpm for 10 min. Overrun increased progressively with MDG concentration but decreased slightly above 10 wt. % due to the difficulty of dispersing air bubbles in such a viscous gel. Considering the effect of whipping speed, and time, it was observed that mixtures reached their maximum volumes within 25 min. With a further increase in the whipping rate, the time required to achieve the maximum amount of foam was decreased. However, at high whipping speed (5400 rpm), foam volume decreased rapidly with time, and almost a lot of foam collapsed. The lowest and highest pH was related to zero and full-fat commercial sauces, respectively. There was no difference between the pH of the control and the linoleic acid containing aerated sauces. Over time, as the pH decreases, the acidity of the aerated sauces increased and making them products with appropriate microbial stability. Due to the significant reduction of fat amount, oxidation of the aerated sauces was much slower than the commercial ones. Appearance, taste, and texture characteristics of aerated sauces provided a sensory profile similar to the full-fat sauce. The aerated sauce containing linoleic acid had higher sensory scores, indicating its general acceptance. Conclusions: In this study, nonaqueous foam as a new approach for fat replacement in emulsion-based foods such as sauces was practically applied. The optimum aeration process conditions were determined by the help of experimental design. Two types of aerated sauces were prepared based on the linoleic acid concentration, and their physicochemical and sensory characteristics were compared with commercial sauces. The acidity and pH of the sauces were in the standard range, and also their oxidative stability was acceptable during storage time. Generally, the aerated sauce containing linoleic acid had relatively similar sensory profiles to the full-fat sauce. Therefore, it seems that nonaqueous foam could be used successfully to create reduced-fat alternative foods, which could also be meet consumers' and marketing requirements.
Food Engineering
Saeid Nejatdarabi; Mohebbat Mohebbi
Abstract
In this study the effect of drying conditions on physical and rehydration properties of foam-mat dried mushroom powder was investigated. Physical properties included moisture content, aw, hygroscopicity, particle size, flowability and cohesiveness, angle of repose, and Tg. The results showed physical ...
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In this study the effect of drying conditions on physical and rehydration properties of foam-mat dried mushroom powder was investigated. Physical properties included moisture content, aw, hygroscopicity, particle size, flowability and cohesiveness, angle of repose, and Tg. The results showed physical properties of mushroom powder significantly (p<0.05) affected by dry temperature. The water activity of mushroom powder was below 0.3, which leads to stable conditions. As decreasing drying temperature, the particle size of mushroom powder increased and led to the increase moisture content and aw. The mushroom powder showed better flowability as increased drying temperature. Tg of mushroom powder ranged from 41.3- 55.6°C. An increase in drying temperature led to increasing wettability and dispersibility. The drying condition had no-significant effect (P<0.05) on the solubility of mushroom powder.
Food Engineering
Fatemeh Heydari; Mohebbat Mohebbi; Mohammad Javad Varidi; Mehdi Varidi
Abstract
The effect of various levels (5, 10 and 15%) of fish protein concentrate (FPC) in batter formulation was investigated. The physicochemical properties of chicken nugget were evaluated in order to find the optimium level of FPC in batter formulation. Flow behavior showed that the control batter and a treatment ...
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The effect of various levels (5, 10 and 15%) of fish protein concentrate (FPC) in batter formulation was investigated. The physicochemical properties of chicken nugget were evaluated in order to find the optimium level of FPC in batter formulation. Flow behavior showed that the control batter and a treatment contains of 7.5% FPC had higher viscosity. Moisture loss and fat uptake in control sample was higher than all treatments contain FPC in both deep fat and air fryer. Thicker crust resulted by higher level of FPC in batter leads less oil uptake during frying. Moreover, the samples contain FPC had the highest score in terms of texture and overall acceptability. In spite the fact that nuggets contain FPC had the high rate of our research priorities, however, the level around 15% considered as a limitation. Using desirability optimization, the range between 7.5- 8% of PFC in batter formulation was selected as the best level.
Food Engineering
Mahsa Kamali Sarvestani; Mohebbat Mohebbi; Masoud Taghizadeh
Abstract
Introduction: Celery is one of the most consumed and highly nutritious vegetables with high dietary fiber, phytochemicals, vitamins, and minerals, which offers great benefits for utilization as a functional food ingredient. Fruit and vegetable juice powders have many benefits and economic advantages ...
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Introduction: Celery is one of the most consumed and highly nutritious vegetables with high dietary fiber, phytochemicals, vitamins, and minerals, which offers great benefits for utilization as a functional food ingredient. Fruit and vegetable juice powders have many benefits and economic advantages over their liquid precursors such as reduced volume/weight, reduced packaging, easier handling/ transportation, and much longer shelf-life. Also, powders can be reconstituted to produce juice and used for preparation of products such as snacks, chutney, soups, baby foods, etc. In foam-mat drying, food liquids and pastes are first whipped into stable foam by the addition of different foaming agents or stabilizing agents and then dried in the form of thin layer. This foam structure dries rapidly due to the increase of the surface area of the material by incorporating air/gas and forms a porous structure which gives high quality and instant properties of the dried product. The dried product is scraped off from the drying surface in the form of flakes, which is then converted to a fine powder. Response surface methodology (RSM) is a combination of mathematical and statistical techniques used to investigate the interaction effects of independent variables on responses. There is considerable information on foam-mat dried food powders, but there is no scientific literature related to foam-mat drying of celery juice. The present research was thus focused on optimizing the foaming conditions (WPC as a foaming agent, Xanthan gum (XG) concentration as the stabilizer and whipping time (WT)) to minimize foam density (FD) and drainage volume (DV) using RSM. The effects of drying temperatures on some physicochemical properties of powder were also investigated. Materials and methods: Celery was purchased from the local market.XG and WPC powders were purchased from Sigma Chemical Company (St. Louis, MO) and Milei Company Germany, respectively. Celery juice was extracted by using a juicer machine (Robert Bosch Stand mixer MMB 2000 /05 FD 8611 Type CNSM03EV, 600W, Slovenia). Based on preliminary tests, XG solutions were prepared by dissolving the appropriate amount of the defined gum powder in distilled water and stirring with a magnetic stirrer to achieve a uniform solution. This solution was refrigerated at 4°C overnight to complete hydration. RSM was used to estimate the main effects of the process variables on FD and DV in celery juice foam. The experiment was established based on a face-centred central composite design (FCCD). According to the experimental design, to prepare 100 g of samples, the appropriate amount of celery juice, WPC, and XG solution were poured to a 250 mL beaker. Then the mixture was placed into a water bath for 5 minutes at 55 °C temperature. The mixture was then taken out of water bath and was whipped by a mixer (Gosonic, model No. GHM- 818, 250W, China) with the maximum speed of 5400 rpm at ambient temperature during the given time. The density of foamed celery juice was determined in terms of mass over volume and expressed in g/cm3. To assess foam stability, the drainage test was performed for 1h. Furthermore, the effects of drying temperatures on some physicochemical properties of powders were investigated. Results and discussions: The quadratic model was selected as a suitable statistical model for both FD and DV. ANOVA showed that this model is significant for both responses. Moreover, lack-of-fit was not significant for response surface models at a 95% confidence level, indicating that this model is adequately accurate for predicting responses. Based on the constrain criteria, the optimized foaming parameters were: XG concentration of 0.42% (w/w), WPC concentration of 6% (w/w), and WT of 9.30 min. The amount of FD and FDV for foam at these optimum conditions were 0.4 g/cm3 and 0 ml, respectively. The results showed the moisture content and water activity of the celery powders decreased with the increase in drying temperature. By increasing drying temperature from 40 to 70 °C, bulk density also decreased. Increase in drying temperature results in decrease in moisture content and bulk density. Tapped density generally behaves similar to bulk density because by shaking powder, the space between the particles is filled and occupied volume by the powder is reduced. By increasing in temperature, particle density decreased. Overall, with increasing drying temperature, the porosity of powder increased. Increasing temperature and reducing moisture content, the possibility of approaching and join together of particles is increased and the space between the particles becomes less. The numerical value of the car index parameter in this study was 15.3% to 24.67%. The highest value of flowability related to the sample was dried at 70°c. With decreasing in drying temperature, the moisture content of powders increased and due to forming liquid bridges between particles making them less flowable. The numerical value of the Hausner parameter in this study was 1.15 to 1.32. Except for powder produced at 70 °C, the powder was placed in the intermediate cohesiveness powder class. By increasing drying temperature, the cohesiveness of powder decreased significantly.
Messiah Sarfarazi; Mohebbat Mohebbi; Mahdi Saadatmand-Tarzjan; Ali Mirshahi
Abstract
Introduction: Chocolate is a suspension of solid particles, including sugar, cocoa solids and milk powder (depending on the chocolate type) in a continuous fat phase, namely cocoa butter or its substitutes. The solid particles account for approximately 70% of chocolate with the fat constituting about ...
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Introduction: Chocolate is a suspension of solid particles, including sugar, cocoa solids and milk powder (depending on the chocolate type) in a continuous fat phase, namely cocoa butter or its substitutes. The solid particles account for approximately 70% of chocolate with the fat constituting about 30%. Sugar takes up nearly 40–50% of the total solid particles of chocolate, thus influencing its sweetness, particle size distribution, rheological and sensory properties. It is also considered to be a bulking agent and a source of energy which produces 394 kcal/100 g of refined sugar. Therefore, consumers are increasingly becoming concerned with chocolate sugar and calorie content nowadays. This issue can be resolved by replacing sugar with bulk (nutritive) sweeteners and/or dietary fibers. Bubbles are found in many food products, including cakes, chocolates and beverages. Although they do not increase the food nutritional value, they change its textural properties and mouthfeel. Bubbles are normally visible to the naked eye and their mean diameter ranges from 0.05 to 3 mm. X-ray computed tomography is a 3D imaging technique which captures the images of a sample cross-sections. It is used for the non-destructive visualization and characterization of food microstructure. In this method, a series of radiographs of a sample are captured from different angles to be utilized for the 3D reconstruction of the material microstructure. Materials and methods: sugar was replaced with inulin: maltodextrin mixture at ratios of 25:75 (CH2), 50:50 (CH3) and 75:25 (CH4). Carbon dioxide was injected into the samples at 6 bar to produce aerated chocolate. Using X-ray computed tomography, the images of the samples were captured and after processing, the obtained images were segmented using the Chan-Vese method. The properties of bubbles included total volume, diameter and surface to volume ratio. The crystallinity of the samples was determined through X-ray diffraction. The hardness of the chocolate bars was measured using the puncture test. The density of the aerated chocolates was also compared with that of the nonaerated ones. Introduction: Chocolate is a suspension of solid particles, including sugar, cocoa solids and milk powder (depending on the chocolate type) in a continuous fat phase, namely cocoa butter or its substitutes. The solid particles account for approximately 70% of chocolate with the fat constituting about 30%. Sugar takes up nearly 40–50% of the total solid particles of chocolate, thus influencing its sweetness, particle size distribution, rheological and sensory properties. It is also considered to be a bulking agent and a source of energy which produces 394 kcal/100 g of refined sugar. Therefore, consumers are increasingly becoming concerned with chocolate sugar and calorie content nowadays. This issue can be resolved by replacing sugar with bulk (nutritive) sweeteners and/or dietary fibers. Bubbles are found in many food products, including cakes, chocolates and beverages. Although they do not increase the food nutritional value, they change its textural properties and mouthfeel. Bubbles are normally visible to the naked eye and their mean diameter ranges from 0.05 to 3 mm. X-ray computed tomography is a 3D imaging technique which captures the images of a sample cross-sections. It is used for the non-destructive visualization and characterization of food microstructure. In this method, a series of radiographs of a sample are captured from different angles to be utilized for the 3D reconstruction of the material microstructure. Materials and methods: sugar was replaced with inulin: maltodextrin mixture at ratios of 25:75 (CH2), 50:50 (CH3) and 75:25 (CH4). Carbon dioxide was injected into the samples at 6 bar to produce aerated chocolate. Using X-ray computed tomography, the images of the samples were captured and after processing, the obtained images were segmented using the Chan-Vese method. The properties of bubbles included total volume, diameter and surface to volume ratio. The crystallinity of the samples was determined through X-ray diffraction. The hardness of the chocolate bars was measured using the puncture test. The density of the aerated chocolates was also compared with that of the nonaerated ones. Results and discussion: X-ray diffraction revealed that there were many strong peaks in the diffractogram of CH1, which can be ascribed to the high degree of sugar crystallinity in addition to the impurities present in the commercial sugar utilized in this study. In the case of the sugar-free samples, namely CH2, CH3 and CH4, two distinct peaks could be seen at 2θ of about 21° and 23.5°, both of which were much stronger and more defined in the scattering pattern of CH3, demonstrating the more crystalline structure of this sample. It seems that inulin and maltodextrin have physically interacted with each other or with the other ingredients of the chocolate, in particular CBS, which has been more pronounced at the ratio of 50:50. The results of image segmentation showed that the Chan-Vese method, compared with the adaptive thresholding one, was more able to segment the images, because this method does not depend on the image gradient and is especially suitable for the objects with vague edges. The mean bubble diameter of CH1 was bigger than that of the other samples, which could be due to its higher degree of crystallinity, because the crystalline structure of CH1 prevented the gas from being lost leading to the coalescence of smaller bubbles and the formation of bigger ones. In addition, it was observed that the density of the aerated chocolate was higher than that of the unaerated one in all the formulas as a portion of solid particles and fat was replaced with the gas. The results also demonstrated that the sugar-free aerated samples were softer than the corresponding nonaerated ones. However, it was reversed in the case of CH1 which could be ascribed to the presence of sugar in this sample, because in aerated products, solid particles, particularly sugar, form a continuous skeleton and play the same role as fat does in nonaerated products.
Olga Azimi; Mohebbat Mohebbi; Reza Farhoosh; Mahdi Saadatmand-Tarzjan
Abstract
Discerning the expiration status (non-rejected and rejected) of edible vegetable oils is very significant because of the hazardous primary and secondary oxidation products. Therefore, it is of outmost importance to monitor the quality and safety of these oils. Based on previous literature, reports and ...
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Discerning the expiration status (non-rejected and rejected) of edible vegetable oils is very significant because of the hazardous primary and secondary oxidation products. Therefore, it is of outmost importance to monitor the quality and safety of these oils. Based on previous literature, reports and experimental observation, the oil color changes during oxidation. Thus, the present study investigates the use of image processing and linear discriminant analysis (LDA) for the classification of non-rejected and rejected edible vegetable oils during oxidation process at 85°C, with respect to the induced period in both primary and secondary oxidation of four oil type (Olive, Sunflower, Palm and Soybean). The purpose of this study was to find less costly and quicker methods with environmental protection, by using the color spaces (RGB, HSI, L*a*b* with Grayscale) instead of chemical analyses to determine the expiration status of edible vegetable oils. Results of this study indicated that the best classification for expiration status of known oils according to induced period of peroxide value in each color space, was achieved with LDA model were for palm with 100% (HSI and Grayscale), olive with 84.61% (L*a*b* and RGB), soybean with 95% (Grayscale) and sunflower with 100% (RGB and HSI), also in induced period of carbonyl value test, the best classification performance was achieved in palm with 100% (L*a*b*), olive with 100% (L*a*b*), soybean with 89.47% and sunflower with 95% (HSI).
Fatemeh Heydari; Mohammad Javad Varidi; Mehdi Varidi; Mohebbat Mohebbi
Abstract
In the present study the cow meat was replaced with camel meat (0, 25, 50, 75 and 100%) in burger formulation. Principal component analysis (PCA) was performed to understand quality variables differences and similarities of thirty-five sample burgers. Score plot, represents Principal component analysis ...
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In the present study the cow meat was replaced with camel meat (0, 25, 50, 75 and 100%) in burger formulation. Principal component analysis (PCA) was performed to understand quality variables differences and similarities of thirty-five sample burgers. Score plot, represents Principal component analysis of datasets derived from evaluated variables of thirty-five samples (samples contain of 0, 25, 50, 75 and 100% camel meat). Overall, six principal component was obtained which 65.8% of the total variance was concentrated into three first PCs. Cooked L*, cooked b* shrinkage, springiness, flavor, texture, juiciness, color and overall acceptability were the variables which separated by the first PC. The PC2 is characterized by the rest of instrumental texture parameters and the third by cooked a* and fat. The evaluation of score plot shows burgers contain higher amount of camel meat (50, 75 and 100%) had the higher moisture and fat content after cooking, higher scores in flavor, texture, juiciness and overall acceptability.
Nasim Hasanpoor; Mohebbat Mohebbi; Arash Koocheki; Elnaz Milani
Abstract
Introduction: Nowadays, frozen dough technology is used to produce bakery, pastry & cakes products. On the other hand, extrusion plays a role as a high-performance process in the food industry, which, given its unique characteristics, can replace many common methods of food processing. This study was ...
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Introduction: Nowadays, frozen dough technology is used to produce bakery, pastry & cakes products. On the other hand, extrusion plays a role as a high-performance process in the food industry, which, given its unique characteristics, can replace many common methods of food processing. This study was carried out aimed to investigate the effect of freezing methods (slow and rapid) and the storage time of frozen dough under freezing conditions on physicochemical and sensory properties of extruded and non-extruded sorghum flour for producing a gluten-free product suitable for Coeliac patients.
Materials and methods: In this study, extruded sorghum flour (an extruder with a temperature of 150-160°C, a moisture content of 14%, a speed of 150 rpm, feeding of 40 grams per minute and circular matrix with a diameter of 5 mm and, in the last step, using a grinding mill and 0.599 mm mesh, flouring is done), non-extruded sorghum flour (100%), Xanthan gum (1% w/w) were used in cookie dough formulation. Two types of slow and fast freezing were used to freeze the dough of cookie. Slow freezing according to the method provided by X.u et al. (2009) and Ke et al. (2013). In a fast freezing method, rapid cooling rooms were used at -40°C for 30 minutes. After freezing, the samples were placed in polyethylene bags and stored for 0, 2, 4, 6 and 8 weeks in a refrigerator at -18°C (X.u et al., 2009). For the thaw process, dough pieces were placed in a refrigerator at + 4°C for 16 hours (Maizani et al., 2012). Baking was performed in a microwave oven at 180°C for 14 minutes. The properties of the final product, such as the ratio of expandability (AACC 10-52), textural properties (cookie texture were carried out using a TA.XTplus Texture Analyzer (Walker et al, 2012)), total gelatinization and enthalpy temperature(Using the DSC device and temperature range 7-157°C and heating temperature 10°C/min), color, percentage of porosity, shell thickness (Image processing technique and ImageJ software) and sensory evaluation were investigated in a completely randomized factorial. Statistical analysis of the results was done using a factorial arrangement of completely randomized design and comparison of the meanings using Duncan's multiple range tests at 5% level. Data analysis was performed with three replications using SPSS 18 software.
Results & discussion: The gelatinization temperature decreased with increasing times of storage; however, the total enthalpy of the process was increased. The results showed that with increasing freezing rate, the gelatinization temperature increased significantly (P≤0.05), and the total enthalpy of the process decreased and the cookie from frozen dough containing extruded sorghum flour has the highest gelatinization temperature and the minimum total enthalpy value. With increasing times of storage, the dough chewiness decreased significantly (P≤0.05) and the adhesion and stiffness of the dough texture increased. The dough chewiness increased with the increase in the freezing rate, however, the adhesion and stiffness of the dough texture decreased and cookie dough containing extruded sorghum flour resulted in a significantly higher chewiness and lower adhesion and stiffness (P≤0.05) of the texture compared to the non-extruded sorghum cookie flour in both methods of freezing. The extensibility ratio has significantly decreased (P≤0.05) with increasing the times of storage. The extensibility ratio of cookie was significantly increased with the increase in freezing rate (P≤0.05) and non-extruded sorghum flour samples showed a lower extensibility ratio relative to the extruded sorghum flour cookies. The dough freezing method also had a significant effect on the final cookie quality (P≤0.05). The stiffness of the cookie texture from the frozen dough decreased by increasing the dough freezing rate and its tissue was softer and cookie samples containing extruded sorghum flour have a significantly lower tissue stiffness compared to other samples. The stiffness of the cookie tissue increased significantly (P≤0.05) with increasing times of storage. L* parameter (lightness) significantly decreased (P≤0.05) with increasing the times of storage and decreased the yellowness factor (b*) and increased the redness factor (a*) significantly (P≤0.05) for the cookie made from frozen dough. The freezing rate had a significant effect (P≤0.05) on the lightness of the cookies. The parameters L* and b* decreased by increasing the freezing rate and the colors of these cookies were darker. Cookies containing extruded sorghum flour had the lowest level of L* and b* and highest level of a*. The porosity% and thickness of crust of cookie decreased significantly (P≤0.05) with increasing times of storage. These parameters increased significantly with increasing freezing rate (P≤0.05) and tissue porosity and thickness of crust of cookies obtained from the frozen dough containing extruded sorghum flour was significantly higher (P≤0.05). The results of the kinetics of cookie mass transfer from frozen dough showed that the effective moisture diffusivity of cookie was reduced by increasing times of storage. Overall, the results showed that the process of extruding sorghum flour has improved the physicochemical properties of the cookie, and the fast freezing process improves the quality of the cookie made from frozen dough, and in this condition extruded flour sorghum can be used as a suitable alternative to wheat. Also, the use of frozen dough for cookie production can be a good way to supply this product.
Shahram Beiraghi-Toosi; Mohebbat Mohebbi; Mehdi Varidi
Abstract
Introduction: Extrusion is one of the technologies used for solid foams production. In this process, pressure is the most important parameter and the most important variables affecting pressure are feed mixture, die diameter, barrel temperature and screw speed. A reduction of die diameter or plasticizer ...
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Introduction: Extrusion is one of the technologies used for solid foams production. In this process, pressure is the most important parameter and the most important variables affecting pressure are feed mixture, die diameter, barrel temperature and screw speed. A reduction of die diameter or plasticizer contents such as moisture and fats in the feed mixture or an increase in the screw speed or barrel temperature can increase the extruder barrel pressure. Also, the increased barrel temperature, in addition to changing cooking properties, escalates the temperature difference inside and outside of the die, raising the rate and amount of evaporation from melted mixtures, therefor affecting the solid foam structure and characteristics. On the other hand, the type and amount of feed mixture components are key factors affecting the extrudate properties (Moraru et al., 2003; Plews et al., 2009; O’Shea et al., 2014).
Sesame seed is one of the ancient edible oil seeds used in many food products. In addition to oil, it contains carbohydrate, protein and fiber (Namiki et al., 2001) which can provide a variety of compounds in the feed mixture to change the properties of foam. This study investigates the effect of partial replacement of corn starch with edible oil seed containing a mixture of various compounds and the effect of the extrusion process on the changes in the physicochemical properties of the produced solid foam relative to the foam produced from corn starch. In this regard, different proportions of sesame seeds were added to the corn starch with specific moisture contents, and following the application of the extrusion process, the effect of feed mixture, operation temperature, screw speed and die diameter on physicochemical properties of solid foams was evaluated.
Materials and methods: Solid foams made from corn starch with 0, 10, 20 and 30 percent of sesame seed in the formulation and 15 percent of moisture content were processed in a co-current twin-screw extruder at a screw speed of 120, 150 and 180 rpm, a barrel temperature of 120, 145 and 170°C, a die diameter of 2.5 and 4 mm, and a constant feed rate of 40 kg per hour. A completely randomized design was employed to investigate the effect of these variables on chemical and physical properties of extruded products. The moisture content of samples was measured using oven method at 105°C (AOAC, 1990). Water absorption and water solubility indices were measured through solving the sample powder in distilled water, which was followed by centrifuging, weighing gel, drying supernatant and weighing dried matter (Singh et al., 2015; Huang et al., 2014). In addition, particle density was measured using the rapeseed displacement method (Singh et al., 2015) and solid density was calculated by the weight /volume ratio of the sample powder, as measured by the gradient cylinder (Ushakumari et al., 2004; Yagci et al., 2008). The porosity of samples was measured in terms of the ratio of particle density to solid density (Plews et al., 2009; O’Shea et al., 2014) and the radial expansion ratio was calculated in terms of the ratio of sample diameter, as measured by the caliper, to die diameter (Chanlat et al., 2011; Huang et al., 2014).
Results and discussion: Results showed that adding 10% sesame seed, due to the variety of compounds and their increased interactions, produced foams of maximum expansion and porosity, and minimum particle density. Adding 30% sesame seed had an opposite effect due to increased fat content and reduced pressure effect on the melted mixture in the barrel. Moreover, increased die diameter demonstrated augmented residual moisture content, water absorption index, density and porosity, as well as decreased water solubility index and expansion ratio of solid foams caused by pressure reduction on the melted mixture in the barrel. The increased barrel temperature was associated with greater changes in cooking, escalated temperature difference between inside and outside of the die and production of foams with higher water solubility index and expansion ratio, as well as lower residual moisture content, water absorption index and solid density. The higher screw speed increased the applied energy, and despite decreasing the time of temperature effect, produced foams with properties comparable to those caused by temperature increase.
In general, it can be stated that the process factors that raise the energy applied to the extrusion material leads to the increased water solubility index and the expansion ratio of the solid foams and decreased residual moisture, water absorption index and density. Consequently, by selecting the right type and amount of feed mixture to create proportions in various compounds and determine the appropriate process conditions, solid foams with desired properties can be produced by means of extrusion using available raw materials.
Sorour Lotfi Shirazi; Arash Koocheki; Elnaz Milani; Mohebbat Mohebbi
Abstract
Introduction: Snack foods have become an important part of the people’s diets. During last decade demands for utilization of fruit and vegetable waste in order to their dietary fibers in value added food products has been increased. Carrot pomace is rich in dietary fiber that contains important functional ...
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Introduction: Snack foods have become an important part of the people’s diets. During last decade demands for utilization of fruit and vegetable waste in order to their dietary fibers in value added food products has been increased. Carrot pomace is rich in dietary fiber that contains important functional and nutritional properties. Barley contains a high amount of dietary fiber, especially soluble fiber, which has essential role in reducing blood cholesterol level.
Materials and methods: In this project based on Central Composite Design, the effect of independent variables containing extrusion temperature (120-170 °C), moisture content (14-20%) and carrot pomace level (10-25%) were evaluated on expansion ratio, bulk density, WAI, WSI, hardness, color snacks were evaluated by panelists in terms of acceptance or non-acceptance.
Results and discussion: Results expressed that expansion ratio, lightness, total acceptability and WAI decreased by increasing the amount of carrot pomace. Reduction of expansion ratio and WSI and improvement of lightness and WAI were shown as increased in moisture levels. The hardness and bulk density decreased with an increase in temperature. When temperature increased up to 145°C, expansion ratio, lightness, WAI and WSI increased and decreased thereafter. The optimum conditions for barley flour-carrot pomace snack were determined at the maximum expansion ratio, L*, WAI and overall acceptability with minimum bulk density and hardness in a snack. The optimum condition provides the highest value of expansion ratio 296.1 (%), L* 65.087, WAI 4.931 (g/g) and overall acceptability 4.502 with lowest bulk density 1.22 (g/cm3) and hardness 6.756 (N). Accordingly, the optimum conditions for the snack are 10% carrot pomace, 148°C die temperature and 15.49% moisture. The approximate composition of the snack extruded and unextruded obtained under the optimal conditions. Extrusion did not affect the protein and ash contents but it decreased the fat content of snack. During the extrusion, the SDF increased from 7.63 to 9.27 g/100g while the IDF decreased from 5.24 to 3.71 g/100g. Extrusion cooking did not affect the TBG content in barley flour-carrot pomace snack. Extrusion cooking resulted in the conversion of insoluble to soluble fiber and well balance of both types of the fiber
Olga Azimi; Reza Farhoosh; Mohebbat Mohebbi; Mahdi Saadatmand
Abstract
Introduction: Discerning the expiration status (rancid and non-rancid) of edible vegetable oils is very significant because of hazardous primary and secondary oxidation products. Oils are a nutritious and valuable food source which play an important role not only in supplying energy but also in sustaining ...
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Introduction: Discerning the expiration status (rancid and non-rancid) of edible vegetable oils is very significant because of hazardous primary and secondary oxidation products. Oils are a nutritious and valuable food source which play an important role not only in supplying energy but also in sustaining a health. Edible vegetable oils such as soya, sunflower, canola, sesame and olive, bring essential nutrient components for human being such as vitamins, fatty acids, and micronutrients, which are necessary for daily life. Lipid oxidation in vegetable oils is associated with unsaturation of the oils. This reaction leads to the formation of a series of intermediate compounds named hydroperoxides. Hydroperoxides are the primary oxidation products of lipid oxidation. Due to the unstable nature of these primary products which leads to their decomposition and turning into secondary oxidation products, such as carbonyl compounds occur soon.
The use of expired edible oils leads to a decrease in the nutrition value and an increase in potential hazards to people's health, so monitoring the quality and security of edible oils is important. Based on the reports and experimental observation the oil color changed during oxidation. Therefore, it is of utmost importance to find new and fast methods for detecting the quality of oils. Computer vision in food sciences is an affordable technology and is extensively used. The aim of this study was to introduce a simple and feasible method for classifying edible vegetable oils (soya, sunflower, canola, sesame and olive) and also for distinguishing their quality in terms of rancidity. In order to achieve this, multivariate statistical methods based on their rejection point of primary and secondary oxidation products was implemented.
Materials and methods: Digital camera and unsupervised multivariate statistical techniques such as linear discriminant analysis (LDA) and principal component analysis (PCA) were used for pattern recognition and classification. In this study, the physicochemical characterization of 77 oil samples includes their peroxide and carbonyl values were evaluated at 80 ◦C. The color indices L*a*b* were used for this classification. The space that was built for imaging was 120cm ×90cm ×90cm with dark walls to isolate the samples from external light. The compartment has a camera (Canon model, EOS 1000D), which was connected to computer by USB port. The illumination of the compartment was performed by using eight fluorescent lamps with 8 W (white color), the lamps were placed at a distance of 20 cm from the samples. The illustration was performed by Zoombrower EX 0.5, the other characteristics of the camera for imaging were as follow: flash (off), zoom (on), Iso speed (100), Aperture priority (F / 20) and Shutter speed (0.6 Sec). The illumination condition at compartment for each sample was the same. Image color analysis was performed using the Image j (Version: 1.4.3.67) software to convert images from R*G*B color space to L*a*b. The recorded images contained 24-bit (16.7 million colors) and 3888 pixels × 2592 pixels spatial resolution and were stored in JPEG format (jpg). A specific region at the center of each image was selected for converting R*G*B to L*a*b. In this study, three components of color space L*a*b* were extracted from 231 images samples ( 77 images of different types of oil before heating, 77 images at the rejection point based on peroxide value and 77 images on the rejection point based on carbonyl value). The extracted color values were used for linear discriminant analysis classification and principal component analysis. The classification was performed using MATLAB (R2013) software
Results & Discussion: The comparison of the results of the linear discriminant analysis showed that distinguishability between the two types of different oils was 100% and only the distinguishing of one oil type in rancid and non-rancid state resulted in a decrease in accuracy to 97%. Also the overall and simultaneous analysis of oil samples in both states (rancid and non-rancid) by the two classifiers of LDA and PCA showed that the classification of each oil individually has the highest accuracy (100%) and the results of the studying several different oils showed a decreased accuracy (98% and 96%). However, in practice, the result of this classification given the diverse colour range of vegetable oils, is acceptable in terms of accuracy and the linear discriminant analysis classifier acted more successfully compared to principal component analysis classifier by about 40%.
Atefeh Pourmahdi; Mohebbat Mohebbi; Ashraf Gohari Ardabili; Mehdi Varidi; Mohammad Reza Salahi
Abstract
Introduction: Potato is one of the most consumed and highly nutritious vegetables with high energy, dietary fiber, phytochemicals, vitamins, and minerals which offer great benefit for utilization as functional food ingredient. The dried potato powder can be used in formulation of many foods like soups, ...
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Introduction: Potato is one of the most consumed and highly nutritious vegetables with high energy, dietary fiber, phytochemicals, vitamins, and minerals which offer great benefit for utilization as functional food ingredient. The dried potato powder can be used in formulation of many foods like soups, snacks, sauces, noodles, etc. The foam mat drying involves the dehydration of a thin layer of foam followed by its disintegration in order to obtain a powder which can be easily reconstituted in water when added to other foods. Because of the porous structure of the foamed materials, mass transfer is enhanced leading to shorter drying times and consequently acquiring higher quality in the dried product. Food foams can be considered as biphasic systems where a gas (dispersed phase) is embedded in a continuous liquid phase. The foam properties such as structure, density and stability have important influence on moisture migration during drying and accordingly, the quality of final product. Foams that do not collapse for at least 1h are mechanically or thermally stable for the entire drying process. Response surface methodology (RSM) is a combination of mathematical and statistical techniques which used to investigate the interaction effects of independent variables on responses. There is considerable information on foam-mat dried food powders, but there is not any scientific literature that related to study on foam-mat drying of potato puree. The present research was thus focused on optimizing the foaming conditions (potato puree: gum solution ratio; Arabic gum (AG) concentration as the stabilizer and whipping time [WT]) to minimize foam density (FD) and drainage volume (DV) using RSM. Likewise, choosing a suitable model for thin-layer drying of foam and the effect of different drying temperatures (45, 60 and 80°C) on drying behavior were investigated, and the effective moisture diffusivity and activation energy were calculated. The effects of drying temperatures on water activity (aw) and water binding capacity (WBC) were also investigated.
Material and methods: Fresh potato was purchased from a local market (Mashhad, Iran). Arabic gum was procured from Sigma Chemical Company (USA). For preparation of potato puree, fresh potatoes were washed and peeled by steel knife and were washed again and additional water was taken absolutely and then crushed by Phillips home crusher (600W) with maximum speed for 3 minutes to get a homogeneous puree. Based on preliminary tests, AG solutions were prepared by dissolving a suitable amount of the selected gum powder in distilled water and stirring with a magnetic stirrer to obtain a uniform solution. This solution was refrigerated at 4°C overnight to complete hydration. RSM was used to estimate the main effects of the process variables on FD and DV in potato puree foam. The experiment was established based on a face-centered central composite design (FCCD). The experimental range was chosen on the basis of the results of preliminary tests. The independent variables were consisted of potato puree: gum solution ratio (1:1 –2:1 w/w), AG concentration (0.1–0.9% w/w) and WT (3–9 min). According to the experimental design, to prepare 100 g of samples, appropriate amount of potato puree and AG solution were mixed in a 250-mL beaker. The mixture was then whipped with a kitchen mixer (model no. SM88, Sonny, China) at a maximum speed of 1,500 rpm at ambient temperature during given time which was recommended by Design-Expert software. The density of foamed potato puree was determined in terms of mass over volume and expressed in g/cm3. In order to assess foam stability, the drainage test was performed for 1h. To evaluate drying behavior of the optimized foam, drying was carried out in a batch-type thin-layer dryer at temperatures of 45, 60 and 80°C on 3 mm thickness. Ten thin-layer drying models were evaluated in the kinetics research. The higher value of R2 and lower values of χ2, RMSE and SSE were selected as the basis for goodness of fit. Fick’s diffusion equation for particles with a slab geometry was used for calculation of effective moisture diffusivity. The foamed potato puree spread on a tray was considered as slab geometry. Activation energy was calculated by a simple Arrhenius-type relationship, by plotting the ln (Deff) against the reciprocal of absolute temperature (1/T). Furthermore, the effects of drying temperatures on aw and WBC of powders were investigated.
Results and discussions: The quadratic model was selected as a suitable statistic model for both FD and DV. ANOVA showed that this model is significant for both responses. Moreover, lack-of-fit was not significant for response surface models at 95% confidence level, indicating this model is adequately accurate for predicting responses. The optimum values of variables for best product quality in terms of minimum FD and DV corresponded to potato puree to gum solution ratio 2:1(w/w), AG 0.77% (w/w) and WT 6.80 min. The amount of FD and DV for foam at these optimum conditions were 0.30 g/cm3 and 5 ml, respectively.
The result showed that when the drying temperature increased, the drying time decreased. This was due to the quick removal of moisture at higher temperature. Drying rate (DR) versus moisture content of potato puree foam-mats figure showed that DR was higher during the initial stage as compared with the final stage and foam-mat drying was occurred principally in the constant rate period. Due to the increase in surface area and the porous structure, removal of water from the inner surface of potato puree foam to the outer surface was fast enough to preserve the surface moisture. The rate of movement of moisture from the inner surface to the exposed surface decreased with decreasing moisture content, which indicates that the DR decreased and the falling rate period started. The effective moisture diffusivity varied from 3.286×10-9 to 8.032×10-9 m2/s with activation energy value of 30.97 kJ/mol. Statistical analysis results showed that the Weibull distribution model provide the highest R2 and lowest values of χ2, RMSE and SSE at all drying temperatures. The temperature elevation reduced aw. This is due to the fact that at higher temperatures, the rate of heat transfer to the sample would increase, therefore, it provides greater driving force for moisture evaporation which results the dried foams with reduced aw. Drying temperatures did not show any significant effect on WBC of powders.
Farnaz Hassanzadeh Rad; Fakhri Shahidi; Mohebbat Mohebbi; Mohammad Reza Salahi
Abstract
Introduction: Kilka Fish is one of the most popular seafood products available for aquaculture development. It is a rich source of proteins, vitamins and minerals such as calcium and phosphor. The highly perishable nature of Kilka fish has strongly attracted researchers to find new methods to extend ...
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Introduction: Kilka Fish is one of the most popular seafood products available for aquaculture development. It is a rich source of proteins, vitamins and minerals such as calcium and phosphor. The highly perishable nature of Kilka fish has strongly attracted researchers to find new methods to extend its shelf life. Kilka fish powder can be used in many foods, such as soups, sauces, snacks, etc. Foam-mat drying is a new effective technique has recently gained much attention because it does not suffer from major problems associated with traditional dehydration methods, such as poor rehydration characteristics, unfavorable sensory profile, and long drying time. The main objectives of this study were: (1) to optimize the effective parameters (egg white powder and xanthan gum concentration, and whipping time) on foaming properties of Kilka fish; (2) to study the effects of drying temperature and foam thickness on the drying characteristics and select a suitable model for thin-layer drying of foam; (3) to compute effective moisture diffusivity and activation energy of foam during drying; and (4) to study the effects of drying conditions on moisture content, water activity, hygroscopicity and color of powders and microstructure of dried Kilka fish foams.
Materials and method: Fresh Kilka fish (C. delicatula) was obtained from the Pak Samar Miroud Company (Mazandaran, Iran). Xanthan gum and egg white powders were purchased from Sigma Chemical Company and Gol Powder Company (Golestan Province, Iran) respectively. The Kilka fish skin removed and cleaned, and then crushed using a kitchen blender to obtain a homogeneous and uniform mixture. Based on preliminary tests, xanthan gum solution was prepared by dissolving a suitable amount of the selected gum powder in distilled water and mixed with a magnetic stirrer to obtain a uniform solution. The resulted solution was cooled at 4°C for 18–24h to complete hydration. According to the experimental design, to prepare 100 g of samples, appropriate amount of fish, egg white powder, xanthan gum solution and distilled water were mixed a 250-mL beaker. The mixture was then whipped with a mixer (Gosonic, model No. GHM- 818, 250W, China) with maximum speed at ambient temperature during given time, which was recommended by Design-Expert software version 6.02 (Stat-Ease, Inc., Minneapolis, MN). Foaming conditions, namely amount of egg white powder, xanthan gum and whipping time, optimized using response surface methodology (RSM) for minimizing foam density (FD) and drainage volume (DV). To evaluate drying behavior of the optimized foam, drying was carried out in a batch-type thin-layer dryer at three drying temperatures (45, 60 and 75°C) on 3- and 5-mm thicknesses. Ten thin-layer drying models were evaluated in the kinetics research. The higher values of R2 and lower values of χ2 and RMSE were selected as the basis for goodness of fit. The effective moisture diffusivity was calculated using method of slopes. A Fick’s diffusion model with slab geometry was used to describe the transport of moisture during drying inside a single Kilka fish foam mat. Activation energy was calculated by a simple Arrhenius-type relationship, by plotting the ln (Deff) against the reciprocal of absolute temperature (1/T). The microstructure of the dried fish foam-mats was analyzed by a scanning electron microscope. Finally, the effects of drying conditions on physicochemical properties of fish powder including moisture content, water activity, hygroscopicity and color were investigated.
Results and Discussion: The optimum values of variables for best product quality in terms of minimum FD and DV corresponded to egg white powder 3.67 % (w/w), xanthan gum 0.28% (w/w) and whipping time 8.93 min. The amount of FD and DV for foam at these optimum conditions were 0.92 g/cm3 and 0 ml, respectively. As expected, the increase in drying temperature and decrease in foam load led to acceleration of the dehydration of Kilka fish foam. Based on the statistical tests performed, Weibull distribution model can describe drying behavior of foams for all drying processes. Moreover, Fick’s second law was employed to calculate the effective moisture diffusivity that varied from 7.266×10-8 to 1.31×10-7 m2/s and from 7.404×10-8 to 1.693×10-7 m2/s with activation energy values of 18.201 and 25.615 kJ/mol for foam thicknesses of 3 and 5 mm, respectively. It was noted that the effective moisture diffusivity was increased when the drying temperature increased. Results showed that at the higher thickness, the internal moisture migration occurs along a longer distance rather than lower thickness. Therefore, an increase in moisture diffusivity occurs both with increase in drying temperature and sample thickness. The analysis of scanning electron microscopy (SEM) micrographs showed that there is wide porous structure of dried foams at higher speeds drying. With increasing drying temperature (due to reduction of drying times), combination of adjacent bubbles and therefor, collapse of foam structure occur less. Higher temperature reduced moisture content and aw , and thickness rise increased moisture content and aw under the same thickness and drying temperature, respectively. This is due to the fact that at higher temperatures, the rate of heat transfer to the sample would increase, therefore, it provides greater driving force for moisture evaporation which results the dried foams with reduced moisture content and aw. Moreover, with increasing foam thickness due to increased drying times and probably collapsed structure of foams and therefor weak pore structure, drying was performed difficultly which causes to retain more water in dried foams. Drying conditions had significant effect on hygroscopicity of powders. Results of color investigation showed that in both thicknesses, powder produced at 60°C have higher L* and lower a*.
Fatemeh Pourhaji; Farideh Tabatabaei Yazdi; Seyed Ali Mortazavi; Mohebbat Mohebbi; Mostafa Mazaheri Tehrani
Abstract
Introduction: Banana is one of the most consumed fruit in the world and is cultivated almost in all tropical countries. This fruit has a high nutritional value and is a suitable source of energy due to the presence of high amount of starch, sugar, vitamin A and C, potassium, sodium, and magnesium. Banana ...
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Introduction: Banana is one of the most consumed fruit in the world and is cultivated almost in all tropical countries. This fruit has a high nutritional value and is a suitable source of energy due to the presence of high amount of starch, sugar, vitamin A and C, potassium, sodium, and magnesium. Banana is highly vulnerable after harvesting and is subject to the microbial spoilage due to the high moisture content which makes difficult its sales and exports. Therefore, several methods have been used to overcome these problems. Drying and dehydration are methods to extend the shelf life of banana which usually carries out by hot air. This method can prevent some degree of microbial spoilage, but it has some disadvantages such as changing color, taste, flavor and reducing the nutritional value.
Foam-mat drying as a substitute for hot air drying introduces some advantages such as using the microwave energy. In this method, food products are whipped to form stable form and then dehydrated by thermal means. Due to the larger surface area and accelerated moisture transfer from foam, food products can be dried at lower temperature and time by this method of drying. Moreover, the porous structure of dried foam results in a faster rehydration and solubility of dried food samples. Additionally, microwave-assisted drying results in a product with better quality because of faster rate and saving energy.
Materials and methods: The fresh banana was cut into small pieces with a diameter of 1.0 mm after peeling. To prevent the enzymatic browning of samples, blanching was carried out by boiling water (100 °C) for 3 min. After that, the banana cuts were placed in a container containing 10°C water in order to cool. To produce pulps, the homemade Bosch mixer (model w600, CNSM, 30EW, Slovenia) at a speed of 1500 rpm and 1.0 min was used. Then, the pulps were mixed with skim milk at different concentrations (3-6 % w/w) and homogenized by ultra-turrax (IKA® Labortechnik) at 10000 rpm for 5.0 min. Moreover; the prepared xanthan gum was added to the mixture at concentrations of 0.15 and 0.25%. Xanthan gum was prepared by adding 1.0 g gum into 100 mL water and mixing by magnet stirrer. Afterwards, the gum solution was kept overnight at 4 °C for complete hydration. Finally, the sample transferred into the foam-maker device which was connected to a nitrogen gas tank with different flow rate (0.2-2 L min-1). The speed and time were adjusted to 16000 rpm and 5.0 min, respectively. After the producing of banana milk foam and selecting optimum sample based on the lowest density and the highest stability, the drying kinetic of this sample was studied. Then the banana milk foam was dried using microwave (360, 660 and 900 V) in a glass plate with diameter of 3.0 and 5.0 mm. Foam density and stability were determined by the methods of Xian-Zheetal (2010), Stauffer (1999) and Bag et al. (2010). The color of samples was studied by hunterlab. Moisture content also was measured based on the AACC standard method (AACC, 2000). Glass transition temperature also was determined by differential scanning calorimetry (DSC, model OIT-500 Sanaf Electronics Co, Iran).
Results and Discussion: In the present study, foam-mat method and microwave drying were used to reduce the drying damages. Nitrogen gas and xanthan gum also were used respectively to control foam generation and improve the stability of foams. Optimization of the banana milk production was carried out using response surface methodology based on three variables including the rate of nitrogen gas (0.2-2 L min-1), concentration of xanthan gum (0.15-0.25 %) and milk to banana ratio (1:6 and 1:3). Optimization was done based on the highest stability and lowest foam density. The optimum condition was proposed as the nitrogen gas rate of 0.2 L min-1, xanthan gum of 0.22 % and 3% banana which showed the density of 0.39 and the highest stability (0 mL after 1.0 h). After that, the optimum sample was dried by microwave. The effects of three levels of microwave voltage (360, 660 and 900 V) and two diameters (3 and 5 mm) were evaluated for drying of optimum sample. The results showed that the sample dried with diameter of 3 mm and voltage of 900 V had the highest L*, highest glass transition temperature and the lowest moisture content.
Elham Ansarifar; Fakhri Shahidi; Mohebbat Mohebbi; Arash Koocheki; Navid Ramazanian
Abstract
Introduction: Microencapsulation has become an important technique in the food industry. One of the methods of producing microcapsules is to use layer-by-layer adsorption, in which oppositely charged polyelectrolytes are adsorbed consecutively onto a colloidal template. Creating multilayer films based ...
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Introduction: Microencapsulation has become an important technique in the food industry. One of the methods of producing microcapsules is to use layer-by-layer adsorption, in which oppositely charged polyelectrolytes are adsorbed consecutively onto a colloidal template. Creating multilayer films based on electrostatic interactions between oppositely charged components was introduced in 1991 by Decher et al. Layer-by-layer (LbL) polyelectrolyte deposition has become a popular technique for preparing polyelectrolyte capsules because of its ability to create highly tailored capsule shells through a simple, inexpensive and easily controllable adsorption process. It has been applied to produce capsules of various sizes, ranging from the nanometer to micrometer scale, with well-defined barrier properties. In this technique, assembly is driven by the electrostatic attraction of oppositely charged materials to form polyelectrolyte shells. The structure of the polyion layered capsule shell is determined mainly by the electrostatic interactions between the polyions used. The mechanical strength and permeability of the capsules can be controlled by varying the number of layers or by changing the characteristics of the encapsulating materials. The purpose of this study was to produce microcapsules using supramolecular assemblies consisting of common food ingredients such as soy protein isolate (SPI) and high methoxyl (HM) pectin. Moreover, some features of the developed microcapsulation were studied.
Materials and methods: SPI fibrils were prepared based on the method developed by Akkermans et al., (2008) and its morphology was studied using transmission electron microscopy (TEM) and atomic force microscopy (AFM). 0.5% (w/w) SPI fibril and pectin solutions were prepared by mixing at pH 3.5 were left stirring overnight. The LbL process for the production of microcapsules with protein fibril-reinforced nanocomposite shells has been described in Humblet-Hua et al., 2012. It starts with the production of A 2% w/w emulsion of (0.05 gr diacetyl in 1.95gr sun flower oil) in fibril SPI solution is produced using a homogenizer with a rotor-stator dispersion tool using a setting of 13500 rpm for 90 S. Because the proteins are below their isoelectic point, the emulsion droplets have a positive charge. To avoid interactions between the nonadsorbed SPI and the biopolymer of the next layer, the droplets are separated from the serum by means of centrifugation. After the isolation, the droplets are dispersed into a solution of HMP. The HMP is negatively charged at the chosen pH of 3.5. The bilayered droplets can be isolated again and dispersed in a fibril solution to deposit a third layer of a positively charged mixture of SPI fibrils. Subsequently, additional layers of HMP and SPI fibrils can be deposited by repeating the same procedures. Some features of the microcapsulation, including size, zeta potential, and morphology and release kinetics were studied.
Results & discussion: TEM and AFM micrographs showed that SPI fibrils obtained had a contour length of a few hundred nanometers, thickness of between 1 and 10 nm and its structure is highly branched. One of the most common problems reported in previous studies using the LbL technique to produce multilayer particles, is the tendency for flocculation. In the present system, this problem was not observed. The size distribution of isolated emulsion droplets (templates) did not change significantly from 1-layer droplets to 5-layer droplets. In other words, the emulsion droplets were stable against flocculation after applying more layers of polyelectrolytes. The Sauter mean diameters D (3, 2) of these droplets fluctuated between 5 and 7 µm and slightly increased as the number of layers increased; noting that the emulsion droplets were poly-dispersed. Another possible problem that may occur using the LbL technique is the complex formation between non-adsorbed protein and the pectin molecules. These complexes with a typical diameter smaller than 1 mm were not detected here. Result showed that the zeta potential distribution of emulsion droplets reverses from about plus (+) 30 mV (odd number of layers with SPI fibrils as outer layers) to about negative (-) 20 mV (even number of layers with HMP as outer layers) confirming the layer-by-layer adsorption based on electrostatic attraction. Comparing SEM of microcapsules with various numbers of layers, an improvement in shell strength can be seen. Indentation is observed on 1-layer microcapsules showing that there are defects on the shell. They could be formed during the drying process or they are shell defects due to incomplete coverage of materials, meaning more layers are needed to fully cover the microcapsule shell. These defects are seen less on 5-layer microcapsules. These observations indicate that the more layers the more consistent the shells and the more resistant. It is against the physical drying process. Results showed that the time of the maximum in release shifts to higher values as the number of layers of the capsules increased. We clearly see that increasing the number of layers in the shell of the capsules leads to a delay of the release of diacetyl and maximum release time as a function of the number of layers is increasing steadily which show the release can be delayed even more by adding additional layers. These results prove that the release properties of the multilayer capsules can be tuned by controlling the number of layers in the shell of the capsules. The modeling results of four different kinetic models are indicated that the Rigter–Peppas was an appropriate model for diacetyl release prediction from multilayer microcapsulation. It could be attributed that the release mechanism is mostly governed by the Swelling–Fickian mechanism.
Conclusion: In this study, the microcapsules were produced using the LbL technique and food-grade SPI fibrils and HMP. The microcapsules had a poly-disperse size distribution. No flocculation of microcapsules during applying of additional layers was observed. It was found that increasing the number of layers, decreases the release rate of diacetyl. The diacetyl release data were kinetically evaluated by zero-order, first-order, Higuchi, and Rigter–Peppas models and the results showed that the release phenomena is mostly governed by the Fickian mechanism. Since the materials are food-grade, the applications of these microcapsules can include food products or pharmaceutical purposes.
Safie Khalilian; Aman Mohammad Ziaiifar; Ali Asghari; Mahdi Kashani-Nejad; Mohebbat Mohebbi
Abstract
Introduction: Thermal properties of food during the frying process and mass transfer mechanisms (water and oil) can help in controlling the quality of the fried product (Fiszman et al., 2005). During the frying process, heat was transferred from the oil to the sample surface that it increases the temperature ...
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Introduction: Thermal properties of food during the frying process and mass transfer mechanisms (water and oil) can help in controlling the quality of the fried product (Fiszman et al., 2005). During the frying process, heat was transferred from the oil to the sample surface that it increases the temperature almost to 100 °C, the water evaporates and moved out. The sample surface was covered by bubble layers with various size and distribution. The formation of vapor bubbles on the samples surface have been effective on the micro-flows which is one of the important factor in the coefficient of heat transfer (Sahin et al., 1999). Therefore, knowledge of the relationship between the boundary layer and the surface heat transfer coefficient can determine the thermal behavior and kinetics of the migration of moisture and oil. Eggplant (Solanum Melongena L.) is one of the major agricultural crops of Asian and Mediterranean countries. Iran after China and India has achieved third place in eggplant production, which has made it remarkable, and economical. Eggplant absorbs high amounts of oil during the frying process due to its high moisture content (more than 90%) and high porous structure even if the residual water content is still quite high after frying.
Materials and methods: Fresh eggplants (Solanum melongena L. family Solanaceae) were obtained from the local market and stored at 4°C. Eggplant samples were washed with water tap and cut with manual mold into equal and similar cylindrical pieces (2.5×1cm). They were then washed with distilled water and surface water was removed using tissue paper. Finally, the samples were packed by poly-ethylene in order to prevent surface drying. A commercial sunflower oil was purchased from Ladan Factory, Iran.
Eggplant samples were dried at different temperature of hot air drying 40, 70, 100 and 130°C until moisture content 5 and 12 db%. Samples were drawn from the drier after drying, cooled at room temperature (25°C) and deep fat fried.
A domestic deep fat fryer with temperature control of ± 1°C (Seb, France) was used for carrying out frying operations. The fryer was filled with 2.5 l sunflower oil. The eggplant to oil ratio was kept at 1:50 w/v to reduce temperature variation in the oil bath. The frying was performed at 130, 150 and 170 °C for regular interval times 1, 2, 3, 4, 5 and 6 min. The frying oil was changed after 10 h of frying time. The samples were immediately removed from oil and were located on wired plate for draining and remove excess oil on the surface, and allowed to cool at room temperature before analyses. All experiments were performed in triplicates and the presented results are the mean of the obtained values.
Oil and moisture content were determined according to AOAC, 1995.
K type thermocouples (copper-nickel) with accuracy of ±1°C were used to measure the temperatures of samples. Temperature acquisition TC-08, Pico® (Technology Limited, England) with accuracy ±0.5°C and temperature controller PID Rex- D-100® (RKC) were used to data collection and oil temperature control, respectively.
In this study, convective heat transfer coefficient was calculated between surface sample and oil according to Farinu and Baik (2008).
In order to predict surface heat transfer coefficients and mass transfer kinetic eggplant samples during deep frying was used artificial neural networks. Then, the 4 inputs including: frying temperature (130, 150 and 170 °C), frying time (1, 2, 3, 4, 5 and 6 min), 4 pre-treatments drying temperature by hot air (40, 70, 100 and 130 °C) until the two moisture levels (5 and 12 %db) were used and output parameters including moisture and oil content, heat transfer coefficient with two replications which in total of 288 data were used to form the network structure.
Results and discussion: Results of this study showed that there is some complicated relationship between convective heat transfer and moisture and oil content. In addition, the convective heat transfer coefficient in up and down surface of the sample showed that oil absorption will be from upper surface. This phenomenon can be attributed to upper surface due to more bubbles of vapor out of the sample. This leads would slower the formation of crust on the upper sample. Finally, channels and cavities of the upper level will be more susceptible to the contact of oil. The results of predictive parameters of heat and mass transfer during deep frying eggplant samples using artificial neural network multilayer perceptron as a non-linear method showed closely relationship with experimental data. It indicates that the proper functioning of this method for modeling and studying the relationship between heat and mass transfer phenomena during deep frying of eggplant samples.
Setareh Hosseinzadeh; Aram Bostan; Mohammad Hossein Hadad Khodaparast; Mohebbat Mohebbi
Abstract
Introduction : Flavors play an important role in consumer satisfaction and influence further consumption of foods. Most available aroma compounds are produced via chemical synthesis or extraction. Foodstuffs containing synthetic flavor in many cases are avoided, because the consumers suspect that these ...
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Introduction : Flavors play an important role in consumer satisfaction and influence further consumption of foods. Most available aroma compounds are produced via chemical synthesis or extraction. Foodstuffs containing synthetic flavor in many cases are avoided, because the consumers suspect that these compounds are toxic or harmful to their health. Recently, the market of flavors is focused in using aromatic materials arriving from natural sources to replace the use of synthetic flavors gradually (Badee, et al., 2012).Flavorsare indispensable ingredients of food preparations, and usually they are in liquid form that makes their handling and incorporating into food more difficult. Furthemore, many flavorcomponents exhibit considerable sensitivity to oxygen, light, and heat. In response to these difficulties, dried flavors have been developed. The objective of this work was to study the influence of different wall material concentration on the emulsion and spray dried flavor powder characteristics.Materials&methods: Spearmint oil was obtained by clevenger distillation method and modified starch was obtained from National Starch&Chemical Limited company (England).Different concentration of modified starch solutions (10, 20 & 30% w/w) were prepared by dispersing the solids in deionized water and heating at 40 ⁰C over a steam bath to facilitate solubilization. Thesolutions were allowed to cool to room temperature before storing at 4°C overnight. The spearmint oil (2.5 % w/w) was added to the solution and was homogenized vigorously (15000 rpm for 10 min.) with an Ultra Turrax homogenizer (T25, IKA, Germany) at ambient temperature. The emulsions were then further emulsified using Ultrasounds (20kHz, 1 min) (Jafari, et al., 2007).The obtained emulsion was spray dried in a BUCHI 190 Spray Dryer (Swiss) with an evaporation rate of 600 lit/1 hour, equipped with a pressurized nozzle operating at 4bar pressure. Feed ismetered into the dryer by a peristaltic pump. Powder was collected at the bottom of dryer cyclone and kept inair tight containers at -18⁰C until analyzed.The particle size of emulsion droplets and spray dried powder were determined using dynamic laser light scattering (Analysette22, Fritsch company, Germany).Encapsulation Efficiency was defined as the percentage of Menthol ad d-limonene thatwere entrapped inside the microcapsules to the total loaded to the emulsion. . Theequations was as follows:Encapsulation Efficiency=(Menthol or Limonene in Microcapsul(ppm))/(Menthol or Limonene in Emulsion(ppm))×100%The powders were attached to SEM stubs using double adhesivetape, coated with 3–5 mA gold/palladium under vacuum,and examined with a scanning electron microscope (S360 model, Oxford , England).Results&disscussion: Emulsion particle size were found to be in the range of 1.8 to 3.3 μm and wall material concentration had significant effect on it ( p
Setareh Hosseinzadeh; Mohammad Hossein Hadad Khodaparast; Aram Bostan; Mohebbat Mohebbi
Abstract
Introduction: Flavor plays a pivotal role in consumer satisfaction and further consumption of foods. Most available aroma compounds are synthetic and most of consumers tend to avoid them as they are of the idea that the chemical flavors are toxic or detrimental to their health. Recently, the market of ...
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Introduction: Flavor plays a pivotal role in consumer satisfaction and further consumption of foods. Most available aroma compounds are synthetic and most of consumers tend to avoid them as they are of the idea that the chemical flavors are toxic or detrimental to their health. Recently, the market of flavors from natural sources is shifting its focus on application rather than synthetic flavors (Badee et al, 2012). Essential oils consist of sensitive compounds against environmental effects. Microencapsulation is one of the methods which increases the stability of essential oils and flavors during storage and transportation. Different methods which may be used for microencapsulation include spray drying, spray-cooling, spray-chilling, coaservation, extrusion, fluidized bed method (KashappaGoud et al, 2003). However, spray drying method is preferred due to its high speed, high reliability, high flexibility and its being economical and the fact that it can be easily implemented in industry (KashappaGoud et al, 2003). Spray drying of essential oils requires homogenizer, spray dryer and chemical materials used for walls such as some types of emulsifiers and ingredients including maltodextrin, dried corn syrup, gum Arabic, gelatin and milk protein (Adamiec&Kalemba, 2004; Badee et al, 2012). Arabic gum (acacia gum) is a biopolymer which is derived from internal sap of acacia tree. It consists of a heteropolysaccharide complex with highly ramified structure (Phisut, 2012). It is an effective emulsifier for flavor emulsions thanks to its high water solubility, low solution viscosity, good surface activity, and ability to form a protective film around emulsion droplets (Chanamai&Mcclements, 2001). Maltodextrins are products of starch hydrolysis, consisting of D-glucose units linked mainly by α(1→4) glycosidic bonds. They are described by their dextrose equivalence (DE) which is inversely related to their average molecular weight. The greater the DE is, the shorter the glucose chains are and the more water they absorb (Phisut, 2012). Materials and method: Spearmint oil was produced by clevenger distillation from spearmint leaves (Mohal Khan et al, 2012). Malthodextrin with DE=18-20 from Xiwang Starch Co. Ltd., China, has a sweet taste and it is used in combination with emulsifiers, creates the walls and covers and causes thermal resistance and resistance to browning. Solubility in water=min 98%, moisture=4.5-6%, pH=4.5-6.5 and ash=max 0.1%. Arabic gum was prepared from Slandwide Corporation Co., Philippines, which is used as an emulsifier, stabilizer and the cover (moisture = max 10%, ash=max4% and pH =4-5).In making an emulsion, deionized double distilled water was used.A Solution of maltodextrin/arabic gum (1:1) in ratios of 10%, 20% and 30% in deionized water were prepared at 45°C and 1200 rpm for 1h (by Stirrer IKA). The solution was kept in cool room temperature at 4°C overnight (Badee et al, 2012; Baranauskiene et al, 2007). Then, 2.5% spearmint oil was added to an aqueous and homogenized (15000 rpm for 10 min) solution with an Ultra Turrax (model T25 digital, IKA Co, Germany) (Badee et al, 2012; Baranauskiene et al, 2007; Baranauskiene&Venskutonis, 2009; Frascareli et al, 2012). Then sonificasion (model ,HD3200, BANDELINE Co, Germany) for 1 minute by amplitude control 100%, frequency 20 kHz at 45 °C. The emulsion was spray dried in a BUCHI B-190 spray dryer (Badee et al, 2012; Baranauskiene et al, 2007; Baranauskiene&Venskutonis, 2009) where the inlet temperature was 180 °C, outlet temperature 60°C, pump speed 10 ml/min, air flow 600 l/h and pressure 4 bar. The powder was stored at -18°C until tested.Results and Discussion: The results of this research showed that during microencapsulation of spearmint oil at the fixed rate of 2.5%, wall concentration were effective in the stability of emulsions and in keeping menthol and d-limonene in microcapsule during drying and storage. By increasing wall material from 10% to 30% the most stability in emulsion was obtained and more half life and less release in microcapsules was achieved. Also, temperature plays an important role in protecting the volatile components, so that the microcapsules stored at 4°C had about half life which was 80 days more than the the samples stored at 25°C.
