Research Article
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.
Research Article
Food Technology
Mohammad Hadian; Mostafa Mazaheri Tehrani; Mohsen Ghods rohani
Abstract
IntroductionDoogh is a fermented dairy product that is produced by blending yogurt with water and some salt. This fermented beverage is widely consumed as a refreshing drink in Iran and other Middle East countries. Doogh is a source of calcium needed by the body on a daily basis and contains B vitamins ...
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IntroductionDoogh is a fermented dairy product that is produced by blending yogurt with water and some salt. This fermented beverage is widely consumed as a refreshing drink in Iran and other Middle East countries. Doogh is a source of calcium needed by the body on a daily basis and contains B vitamins that are effective in the health and strength of teeth and bones. In addition, doogh contains a low percentage of fat, which makes it a diet drink. Whey Protein Concentrate (WPC) is a product contains 25 to 89% protein and different amounts of lactose, fat and minerals. Due to the functional properties of whey protein and its nutritional value; whey protein is widely used in dairy products. The development of cross-linking bonds between protein chains by enzymes is very important today. Enzyme cross-linking of proteins can affect some of their functional properties such as solubility, water absorption, rheological and emulsifying properties. One of the most widely used enzymes in the food industry is the transglutaminase enzyme. In this study the effects of WPC in three levels (0%,1% and 2%) and the transglutaminase enzyme in two levels (0 and 1 unit per gram of milk protein) in two method of dough preparation (adding water to yogurt and fermented milk diluted with water) on rheological characteristics, and microstructure of doogh were studied. Material and MethodsRaw milk was provided by Pegah Khorasan Company, WPC from Multi Company) Mashhad (and Trans glutaminease enzyme from BDF Company of Spain. WPC was first added to milk at 45 ̊ C at three levels of zero, 1 and 2%.The milk samples were then pasteurized at 85 ̊ C for 30 min. After lowering the temperature to 45 ̊ C, the enzymatic operation was performed at two levels of zero and one unit (per gram of protein).To complete the enzyme function, the samples were incubated for 180 minutes at 45 ̊ C. Then a temperature of 90 ̊ C was applied for 1 minute to inactivate the enzyme. The samples were then cooled to 45 ̊ C. At this stage, the samples were divided into two parts. In one part of the samples; milk was diluted with water in a ratio of 6% of the total dry matter for direct production of doogh. After adding the starter, the samples were transferred to an incubator and hold at 43-42 ̊ C, until the pH reaches about 4.1.Thefermented samples were then transferred to a refrigerator. In the second part, starter was added to milk to produce yogurt; after adding starter, the mix was transferred to an incubator and hold at 43-42 ̊ C, until the pH reaches about 4.1. Doogh was produced by diluting yogurt with waterto givethe final product with 6% of total dry matter. Results and Discussion In both production methods, in samples treated only with WPC, the average particle size increased with increasing WPClevel. In both methods, the production of only enzymatically treated samples led to the formation of smaller particles with a more uniform shape and distribution. In samples of doogh produced by both production methods, WPC and transglutaminase enzyme changed the flow characteristics of doogh to non-Newtonian behavior. Samples made directly from milk had significantly higher viscosity than samples made from yogurt. In samples without enzymatic treatment, the microstructure was smooth and homogeneous with smaller particles than other samples. These particles settle very quickly. In the samples where WPC treatment was applied, the amount of large particles and non-uniformity increase with increasing WPC level. The distribution of particles in samples made directly from milk was more regular than samples made from yogurt.
Research Article
Food Biotechnology
Behrooz Alizadeh Behbahani; Mostafa Rahmati-Joneidabad; Mohammad Noshad
Abstract
IntroductionThe use of safe ingredients to preserve food is steadily increasing. The high time and cost of production and approval of synthetic food additives and the reduction of public acceptance of these compounds have caused serious problems in their utilization. Excessive use of synthetic preservatives, ...
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IntroductionThe use of safe ingredients to preserve food is steadily increasing. The high time and cost of production and approval of synthetic food additives and the reduction of public acceptance of these compounds have caused serious problems in their utilization. Excessive use of synthetic preservatives, which some of them are suspected to be toxic, has completely eliminated these additives and led to the use of natural alternatives to preserve or extend the shelf life of food products. Many plant-based bioactive compounds are good alternatives to synthetic antimicrobial and antioxidant supplements. Plant extracts have significant biological activity including antioxidant, antibacterial, and antifungal properties, which has increased their use in food products. In addition, plant-derived antimicrobial compounds have been considered in the pharmaceutical industry to control microbial pathogens. Natural antioxidant and antimicrobial compounds are receiving a lot of research and industrial attention in food preservation technologies. In the last 2 decades, the use of herbal medicines rich in bioactive molecules (including polyphenols, carotenoids and flavonoids) with medicinal and health effects such as delaying the onset of some diseases such as cardiovascular disorders, diabetes, and cancer have increased.The plant Prosopis farcta grown in arid and semi-arid regions. In Iran, it is found in the southern regions of the country. In traditional medicine, this plant is used to prevent hyperlipidemia and hyperglycemia, to treat hemorrhoids, intestinal diseases and diarrhea, and leprosy, and to reduce abortion. In addition, antimicrobial and antioxidant properties of various species of Prosopis have been reported. Accordingly, in this study, after examining the of total phenols and flavonoids concentrations, the antioxidant and antimicrobial properties of ethanolic extract of Prosopis farcta were determined. Materials and MethodsThe ethanolic extract of P. farcta was obtained maceration method. Total phenol content (by Folin-Ciocalteu reagent method), total flavonoid content (by aluminum chloride method), antioxidant activity (by DPPH and ABTS free radical scavenging and beta-carotene bleaching methods), and antimicrobial effect against Escherichia coli, Shigella dysentery, Staphylococcus aureus, and Bacillus subtilis (by disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration) of the extract were evaluated. Results and Discussion farcta ethanolic extract showed high phenol content (145.58 ± 1.30 mg GAE/g), while its total flavonoid content was 72.37 ± 1.48 mg QE/g. Antioxidant activity of ethanolic extract of melon root using different methods of DPPH and ABTS free radical scavenging and beta-carotene bleaching inhibition were 62.60, 71.82 and 54.50%, respectively. Antibacterial activity of P. farcta ethanolic extract against Escherichia coli, Shigella dysentery, Staphylococcus aureus, and Bacillus subtilis according to disk diffusion agar and well diffusion agar methods showed that the antimicrobial activity of the extract was concentration dependent and Shigella dysentery and Staphylococcus aureus were the most resistant and sensitive bacterial strains to the extract respectively. The minimum inhibitory concentrations of ethanolic extract of P. farcta root for Escherichia coli, Shigella dysentery, Staphylococcus aureus, and Bacillus subtilis were 8, 8, 4 and 4 mg/ml, respectively; while the minimum bactericidal concentrations for these bacteria were 128, 256, 32 and 64 mg/ml, respectively. ConclusionIn the present study, ethanolic extract obtained from the roots of P. farcta was identified as a rich source of phenolic and flavonoid compounds. The ethanolic extract showed effective antimicrobial and antioxidant properties. The results greatly indicated the promising effect of P. farcta root extract against Gram-positive and Gram-negative bacterial species. As the microbial resistance is constantly increasing, ethanolic extract of P. farcta root can be considered as a suitable complementary option to tackle this problem. In addition, the identification of individual components of P. farcta ethanolic extract and their biological functions or their combination with common antioxidant and antimicrobial agents could be the subject of future research.
Research Article
Food Technology
Ghazal Shekari; Elnaz Milani; Elham Azarpazhooh
Abstract
IntroductionCeliac disease is one of the most common digestive disorder. Chicken nugget is one of the most popular instant and ready-to-eat foods, and wheat flour is one of its main coating ingredients, which contains approximately 60% gluten. Quinoa is a gluten-free grain, as a good source of dietary ...
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IntroductionCeliac disease is one of the most common digestive disorder. Chicken nugget is one of the most popular instant and ready-to-eat foods, and wheat flour is one of its main coating ingredients, which contains approximately 60% gluten. Quinoa is a gluten-free grain, as a good source of dietary fiber, has various applications in the meat products processing system as a stabilizer, fat substitute, structural components, etc. The addition of hydrocolloids also helps to improve the rheological properties of gluten-free products. The purpose of this research was to evaluate the effect of quinoa-corn mixed flour in the preparation of nugget batter as a gluten-free combination as an alternative to wheat flour, and also to investigate the effect of adding HPMC hydrocolloid on the final product characteristics. In this research, a rotatable central composite design was used to investigate the effect of two independent variables including different proportions of quinoa-corn flour (0-100, 50-50, 100-0%) and different levels of hydrocolloid (0.5-1-1.5%) on the quality characteristics of nugget. With the increase of quinoa replacement level, moisture content (0.60), batter pick up (138) and redness level 5.5 (a*) increased, and oil content (11), hardness (7.5), brightness level 41(L*), yellowness level 20(b*) decreased. The increase of HPMC also caused an increase in moisture content (0.59), brightness level (L*) of 0.39, batter pick up (137) and decrease in oil content (10) and hardness (7). Optimum conditions for the production of gluten-free nugget were determined by considering the optimal amounts for the production of high quality and healthy products, contained 90% quinoa and HPMC at a level of about 1%. Materials and Methods Corn flour was purchased from the pilot of Ferdowsi University of Mashhad. The de-saponified quinoa was prepared from Kashmir and then ground. In order to make the grains more uniform, both flours were sieved using a 30 mesh. Hydrocolloid hydroxypropyl methylcellulose was also prepared from Kian Shimi Mashhad. Oyla frying oil was used for frying the samples.The chicken nugget formulation was a mixture of 86% minced chicken, 10% onion, 1.5% garlic powder, 1% salt and 1.5% pepper. After complete mixing, these materials were poured into a freezer bag until a homogeneous and uniform mixture was obtained, and they were flatted until they reached the desired thickness (1 cm). Plastics containing chicken paste were stored in the freezer for 2 hours to facilitate cutting. Then molding was done with a circular mold with a diameter of 4 cm (Dehghan Nasiri et al., 2012).The batter formulation consisted of flour, water, baking powder, salt and hydrocolloids. In order to investigate the effect of quinoa and corn flours, and hydrocolloids, these substances were added to nugget water paste in different percentages (quinoa-corn ratio: 0-100, 50-50, 0-100 and hydrocolloids at the level of 1-1 / 5 -0.5%) and then mixed with water by mixer for 1 minute. The molded samples were first coated with flour and then immersed in the batter for 60 seconds and dripped for 30 seconds. Finally, deep frying was performed in the fryer at 170 ° C for 3.5 minutes. The fried samples were taken out of the fryer basket and the excess oil on the surface of the nuggets was removed with absorbent paper. The oil was changed after twice frying. After cooling the samples at room temperature, the tests such as moisture content, oil content, texture (hardness), color, batter pick up, peroxide and overall acceptance were performed.In this study, Design Expert 10.0.7 software and a rotatable central composite design to investigate the effect of two independent variables including different ratios of quinoa-corn flour (0-100, 50-50, 0-100%) and hydrocolloid (0.5-1-1.5%), Was used on the quality characteristics of the nugget. Finally, different models were fitted to the data obtained from the experiments and the best model was selected according to the results of analysis of variance. Results and DiscussionWith increasing quinoa replacement level, moisture content, redness (a*) and pH increased and oil content, batter pick up, texture (hardness), brightness (L*), yellowness (b*) and cooking loss decreased. Increasing the HPMC also increased the moisture content, brightness (L*), cooking loss, batter pick up, and decreased oil content and hardness. Optimum condition for production of gluten-free chicken nuggets, considering the appropriate properties was found to be 90% quinoa flour and 1% HPMC. Conclusion In general, it can be concluded that the addition of quinoa and HPMC leads to the production of high quality products with high moisture and low oil content and high nutritional value.
Research Article
Food Engineering
Mosatfa Soleymani; Vahid Hakimzadeh; Mostafa Shahidi Noghabi; Akram Arianfar
Abstract
IntroductionAppropriate and effective decolorization of raw and thin juice in sugar refineries is considered as an important process to obtain premium quality sugar, which due to the problems of its conventional process, membrane processes as effective and environmentally friendly processes can be used ...
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IntroductionAppropriate and effective decolorization of raw and thin juice in sugar refineries is considered as an important process to obtain premium quality sugar, which due to the problems of its conventional process, membrane processes as effective and environmentally friendly processes can be used in parts of sugar industries. Among the disadvantages of the usual methods to remove membrane fouling, it can be mentioned the destruction of the membrane, environmental pollution, the remaining detergents in the membrane and the product, especially in the pharmaceutical and food industries, and the increase in production costs. Therefore, it seems that physical methods such as pre-filtration of the incoming feed, using turbulent and pulse currents to prevent excessive compression of the gel layer formed on the membrane surface are more effective and have fewer disadvantages. One of the ways to change the flow of feed entering the membrane surface is bubbling, which causes mixing the flow and increases the tangential shear stress. In fact, the hydrodynamic force that creates bubbles causes both the dragging force and the lifting force and leads to the removal of fouling and reducing the phenomenon of concentration polarization. Materials and Methods In this research, an ultrafiltration membrane (MWCO=10 KDa) pilot with a flat module (effective surface 40 square centimeters) was used to purify raw beet juice (which had passed a stage of pre-treatment with microfiltration) at the temperature of about 30 degrees Celsius and a trans membrane pressure of 3.5 bar during the process. Nitrogen gas in the amount of 0.5, 1 and 1.5 liters per minute was used in two continuous and interrupted modes for bubbling. In this way, in the interrupted mode, after every 3 minutes of filtration, the filtration process was carried out with gas for one minute. The factors such as flux, fouling and membrane resistance as membrane efficiency's factors and parameters like color, purity and turbidity as purification factors was investigated in the form of a completely random design and compared with control filtration conditions (without bubble generation). The results of this research were statistically analyzed using SAS (version 1.9) and Microsoft Office Excel 2019 software. The average data of each test in three repetitions was compared with the least significant difference (LSD) test at the 95% level. Results and DiscussionIncreasing the amount of gas during the bubbling process improved the flow rate. Also, the results showed that the decreasing trend of the permeate flux at the gassing rate of 1.5 L/min was less than other treatments and more stable conditions were seen in the sap flux during the process. Also, the amount of flux in the interrupted form of bubbling showed that after the application of bubbling, although the amount of flux increased, but after that, during the ultra-refining process, the flux decreased again and did not remain constant at that level. But in general, despite the fact that the average flux was higher in the continuous process compared to the interrupted state, there was no significant difference between them. The results related to the amount of membrane fouling after applying the process showed that by applying bubble generation in both continuous and interrupted mods, the fouling was significantly reduced compared to the usual state of ultrafiltration. Also, as the amount of gas entering the feed stream increased, the membrane fouling decreased, which was slightly higher in the continuous state than in the interrupted mod. The overall hydrodynamic resistance of the membrane in different filtration modes showed that the difference between the overall resistance of the membrane in the ultrafiltration and the ultrafiltration process with gasification is quite significant. However, although the overall resistance of the membrane in the interrupted gassing state is higher than its continuous state due to more clogging, there is no significant difference between them (P<0.05).Since the flux changes and the amount of gel layer formation affect the properties of the purified syrup, the properties of the syrup were also investigated in the best flux created in two continuous and interrupted modes. The results showed that the continuous flow of gasification caused a small defect in the purification properties such as purity, color and turbidity due to the improvement of the permeate flow flux, which of course can be ignored in the sugar industry due to the improvement of the permeate flow flux. ConclusionTherefore, in general, it can be said that the discontinuous method, due to less gas consumption during bubbling and no significant difference in the amount of flux compared to the continuous mode, can be considered as the optimal mode of gasification during the experiments conducted in this research be placed.
Short Article
Food Technology
Maryam Khosravani; Seyyed Moein Nazari; Gholamhasan Asadi
Abstract
Introduction In recent years, increasing consumer awareness of the dangers of consuming high-fat products, sensitivity to proper nutritional patterns and the impact of health factors has increased consumer demand for low-fat or free-fat foods. Scientific researchers have provided a great quantity ...
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Introduction In recent years, increasing consumer awareness of the dangers of consuming high-fat products, sensitivity to proper nutritional patterns and the impact of health factors has increased consumer demand for low-fat or free-fat foods. Scientific researchers have provided a great quantity of evidence between the consumption of high-fat products and the development of diseases such as obesity, hardening of the arteries, chronic hypertension, etc. Fat removal is not an easy task because fat, in addition to nutritional aspects, affect rheological and sensory properties such as mouth feel and texture properties of the final product. Using alternative materials that can be completely or partially replaced fat in the formulation of low-fat products by imitating the properties of fat is great important. Unlike fat, which its high consumption causes many problems; fiber can play a vital role in many of the nutritional, functional, and sensory properties of food products, Some types of fiber act as fat substitutes, while producing less energy, provide a large effect of fat function properties. Increasing consumption of easy-cook meat products such as sausages induced replacement the fat content in the formulation of these products, by fat substitutes such as maltodextrin. The aim of this study was to evaluate the chemical and sensory properties of low fat German sausages produced by maltodextrin. Materials and Methods In this study, 0, 6, 12, and 18% of fat was replaced by maltodextrin in the formulation of German sausage. The chemical and sensory properties were then investigated. Chemical properties including moisture, protein, ash, and fat were accomplished according to the ISIRI standard. Evaluation of sensory properties was done by 5-point hedonic method according to Click et al. (2006). Data analysis was performed using SPSS software in a completely randomized design with a 95% confidence level. Results and Discussion The results showed that with increasing the level of maltodextrin, the amount of moisture, ash, and starch of sausage samples increased significantly. As the concentration of maltodextrin increased, the protein content of the samples decreased. The highest protein content observed in the control sample and the sample contained 6% maltodextrin and in contrary, the lowest protein content was in the sample containing 18% maltodextrin and there was no statistically significant difference between the test samples (p>0.05). Changes in maltodextrin concentrations had a significant effect on the fat content of sausage samples so that with increasing the concentration of maltodextrin in the sausage formulation, the fat content of the samples decreased (p≤0.05). Also, with increasing the percentage of maltodextrin replacement in German sausage samples, the cooking yield decreased significantly (p≤0.05). In the evaluation of sensory properties, it was found that the use of maltodextrin reduced the score in all parameters studied so that the lowest score in terms of color, texture, flavor, and total acceptance of sausage samples was related to sample with 18% maltodextrin replacement. Conclusion The vital role of the effect of dietary fiber on improving and managing the health has been proven by researchers for many years. Due to the need to reduce fat in products such as sausages, which considered as a popular meat product and based on the results observed in the present study, it is recommended to use maltodextrin fiber at the level of 6% as a fat substitute in the formulation of German sausages.
Research Article
Food Engineering
Saeede Hamidi; Nafiseh Zamindar; Nayyere Gholipour Shahraki
Abstract
IntroductionThermal processing is an important method of canned food production (Farid & Abdul Ghani, 2004). Estimation of the heat transfer rates is essential to obtain optimum processing conditions and to improve product quality. In addition, a better understanding of the mechanism of the heating ...
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IntroductionThermal processing is an important method of canned food production (Farid & Abdul Ghani, 2004). Estimation of the heat transfer rates is essential to obtain optimum processing conditions and to improve product quality. In addition, a better understanding of the mechanism of the heating process will lead to an improved performance in the process and to some energy savings (Abdul Ghani et al., 1999). Computational fluid dynamics (CFD) is an efficient way to study flow behavior and temperature distribution of thermal processing in the food technology (Ghani et al., 2003). As the semi-rigid aluminum packaging market recently has been introduced, there is limited information about the temperature distribution during the heating process of such containers. In this paper the temperature distribution was predicted and location of cold zone was determined. The effect of headspace (air and water vapor) in heat transfer mechanism was investigated. Materials and MethodsPhysical propertiesMalt extract properties such as density, specific heat, thermal conductivity and viscosity values are necessary for the equations solution. Viscosity and density of the sample was measured as a function of temperature (Vatankhah et al., 2015). Specific heat and thermal conductivity of sample were estimated using the mass fraction of its constituents. For simulation, the experimental results were applied by piecewise-linear method in the material part of the software to describe viscosity, thermal conductivity and specific heat. Experimental methodologyFor the experimental, a thermocouple probe was located at point (0, 0, -2.76) in a semi rigid aluminum based packaging to measure the temperature distribution inside the container. Then the package was filled with malt extract (°Brix ~ 60) and then the package was sealed at 280 °C using Alcan machine. Another thermocouple was placed near the containers, in the water cascading Barriquand steriflow retort. The thermocouples were attached to Ellab data logger by PT100 cables. The data logger was connected to a personal computer and E-val 2.1 software was used to export time temperature profile of each thermocouple in 1 min intervals. Geometry and meshingGambit 2.3.30 was used to develop geometry and set of grid (0.2 cm, and 0.1 cm mesh size) was performed. Then software of fluent 6.3.26 with 3-D, double precision, pressure-based solver, implicit formulation, unsteady time, laminar flow was applied to solve the system of the governing equations (Vatankhah et al., 2015). Boundary conditions and initial valuesUnsteady temperature function was imposed to all faces of the geometry in 1 min time intervals. No-slip boundary condition was supposed for velocity components relative to boundaries. The boundary conditions used at top surface, bottom surface and side walls included: T = Tw, Vx = 0, Vy = 0 and Vz = 0. The initial temperature was assumed as the first temperature which was measured by the thermocouple at the starting time of processing. Solution methodologyFluent software was used to solve the Navier-Stokes and energy equations simultaneously. A preset convergence limit of 10−3 for continuity and momentum equations and 10−8 for the energy equation were used, in order to achieve an appropriate convergence. The under-relaxation factors were adjusted smaller than 1 to obtain a good convergence of the numerical solution. SIMPLEC algorithm was used for pressure-velocity coupling. Results and DiscussionThere was no significant difference between predicted and experimental temperatures for point (0, 0, -2.76) in models with and without head space using t-test (p<0.01). Temperature contours of predicted models (with headspace) were similar to model without headspace at the different stages of the process. Simulation result showed slowest heating zone located in (0.02 <X< 0.8, -1 <Y< 0.3 and -3.27<Z< 3.27) for model of malt extract with headspace and in (-3.58 < X< 3.76, -3.44 <Y< 0.48 and -3.46 <Z< -3.05) for model of malt extract without headspace. ConclusionThe heating process of malt extract in semi rigid aluminum container during thermal processing was simulated successfully using CFD. The CFD based model showed that the position of SHZ was located in the third end of the container.
Research Article
Food Biotechnology
Soheyl Reyhani Poul; Sakineh Yeganeh; Zeynab Raftani Amiri
Abstract
Introduction Since heat treatments and special standards are not used in the production of traditional (homemade) tomato paste, fungal and bacterial spoilage in the product occurs extensively during storage in the refrigerator (4°C). Astaxanthin extracted from aquatics has antimicrobial activity ...
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Introduction Since heat treatments and special standards are not used in the production of traditional (homemade) tomato paste, fungal and bacterial spoilage in the product occurs extensively during storage in the refrigerator (4°C). Astaxanthin extracted from aquatics has antimicrobial activity and color similar to tomato and can probably be effective in preventing spoilage of tomato paste. In addition, astaxanthin has other properties in the field of preventing and controlling diseases and maintaining human health, which justifies its use in food formulations as an enrichment. Since heat, enzyme, acid, etc. treatments are practiced during the production of tomato paste, these factors may change the structure and thus the function of astaxanthin. For this reason, astaxanthin nanoencapsulation is necessary for its use in tomato paste formulation. Materials and Methods In this research, first, astaxanthin was extracted from Haematococcus pluvialis microalgae using the acid-acetone combined method. Then, this pigment was nanoencapsulated using maltodextrin-sodium caseinate coating and the resulting nanocapsules were used together with the pure form of astaxanthin in the formulation of tomato paste. The research treatments were control, tomato pastes containing 3 and 6% astaxanthin (A and B, respectively) and also 3, 6 and 9% nanocapsules carrying the pigment (C, D and E, respectively). These treatments were kept at refrigerator for 28 days and were evaluated (on days 0, 7, 14, 21 and 28) in terms of the total number of fungi, Howard's number (HMC), pH, fungal flora, total bacteria count, amount of lactic acid bacteria and sensory properties. This research was conducted in a completely randomized design. Data were analyzed by One-way Anova and the difference between the means was evaluated by Duncan's test at 95% confidence level. Results and Discussion The results showed that the fungi proliferation, total count and lactic acid bacteria were slower than the control during the storage period in the treatments containing astaxanthin and its carrying nanocapsules, and the minimum number of the mentioned microorganisms and Howard's number were related to treatments D and E (p>0.05). Treatments C, B and A were ranked next in this respect (p<0.05). The number of fungi in two treatments D and E from day 0 to 28 varied from 128 to 332 cfu/gr. Also, the Howard number of these treatments was recorded from 18 to 34% in the mentioned time period. However, these two indices in the control ranged from 121 to 792 cfu/gr and 18 to 91%, respectively, during the storage period. The count of total bacteria and the amount of lactic acid bacteria in the control on day 28 were equal to 8.9 cfu/gr and 311 mg/kg, respectively, but these two values were recorded in the E and D treatments on the same day, about 4.8 cfu/gr and 110 mg/kg, respectively. Counting the total number of fungi, bacterias and also Howard's number in control and other treatments showed that the effect of nanocapsules carrying astaxanthin on microbial growth and proliferation is significantly greater than pure astaxanthin (p<0.05). The pH of the treatments varied from 3.9 to 5.8 during the storage period and the most standardized pH (3.9-4.4) was recorded in C, D and E (p>0.05) treatments (p<0.05). The pH of two treatments A and B (p>0.05) was higher than the three mentioned treatments and lower than the control (p<0.05). This finding showed that nanocapsules carrying astaxanthin have a greater effect on controlling the pH of tomato paste than pure astaxanthin during storage at refrigerator (p<0.05). The identification of the fungal flora of the treatments on the 28th day confirmed that two genus of Penicillium and Aspergillus form the main flora of the product. The results of the sensory evaluation of the treatments on day 0 showed that adding astaxanthin and its carrier nanocapsules does not change the color, aroma, taste and texture indicators (subsequently the general acceptance) of tomato paste (p>0.05). On the 28th day, the mentioned sensory indices only in the two treatments D and E were not significantly different from the 0 day, but they changed negatively in the other treatments (p<0.05). Conclusion According to the findings of the present research, astaxanthin extracted from Haematococcus pluvialis microalgae has the ability to inhibit fungal and bacterial spoilage and stabilize the sensory properties of tomato paste stored at refrigerator. This properties were improved by adding nanoencapsulated pigment using maltodextrin-sodium caseinate combined coating. Since there were no significant differences between the two treatments containing 6% and 9% of nanocapsules carrying astaxanthin (D and E) in terms of quality indices and microbial spoilage, therefore, the treatment containing 6% nanocapsules is introduced as the optimal treatment.
Research Article
Food Biotechnology
Mahdieh Mostafidi; Mohammad Reza Sanjabi; Naheed Mojgani; Sohyel Eskandari; Sepideh Arbabi Bidgoli
Abstract
Introduction The food and water contamination with heavy metals is increasing due to the environmental pollutions. Heavy metals are the elements with the density of more than 5 g/cm3 and have become a serious problem as a result of the urbanization and industrialization. These toxic metals pollute ...
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Introduction The food and water contamination with heavy metals is increasing due to the environmental pollutions. Heavy metals are the elements with the density of more than 5 g/cm3 and have become a serious problem as a result of the urbanization and industrialization. These toxic metals pollute water, soil, plants, and eventually foodstuffs and our bodies. Several methods exist to remediate heavy metal pollution in waters such as membrane filtration, ion exchange mechanisms, or by precipitation. Yet, these techniques are not cost effective, in some cases, and do produce wastes that need to be properly disposed of. Microbial bioremediation could be an alternative. The use of microbes for remediation of heavy metals has been well studied. Some microorganisms, especially soil bacteria, have the ability to tolerate these contaminants. In addition, certain bacterial strains are capable of binding to heavy metals or transforming them into less toxic forms. Low operating costs, usable in foodstuffs, selective removal for specific toxic metals, minimal use of chemicals (resulting in low sludge production) and high efficiencies at very low levels of heavy metals are some of the advantages of biosorption methods. In this regard, the purpose of this study was to investigate the ability of active and passive absorption of heavy metals by a number of Lactic Acid Bacteria (LAB) strains in laboratory environment and food. Materials and Methods Seven LAB isolates including Lacticaseibacillus casei (RTCC 1296-3), Lacticaseibacillus rhamnosus (RTCC 1293-2), Lactiplantibacillus plantarum (RTCC 1290), Limosilactobacillus fermentum (RTCC 1303), Enterococcus faecium (RTCC 2347), Lactobacillus helveticus (RTCC 1304) and Lactobacillus acidophilus (RTCC 1299) were obtained from Razi type culture collection (RTCC), located at Razi vaccine and Serum Research Institute, Iran. All isolates were cultured in MRS (Scharlau, Spain) broth medium, at 37 °C for 24 hours, under anaerobic conditions. Pure cultures were preserved for long term by freezing at -70°C with 20% Glycerol. Heavy metals including Nitrate of Pb (II), Cd (II) and Ni (II) were purchased from Merck (Darmstadt, Germany). All standard solutions were prepared from the stock solutions containing 1000 mgl-1 in distilled water. Other chemicals used in study including Nitric acid (65%) and Hydrogen peroxide (37%), were also purchased from Merck, Germany. This study was conducted in two in- vitro and in-vivo phases; in the in- vitro phase, seven strains of bacteria with probiotic properties (L. casei, L. rhamnosus, L. plantarum, L. fermentum, Ent. facium, L. helveticus and L. acidofilous) were screened and then their ability to bind to cadmium (Cd), Lead (Pb) and nickel (Ni) in aqueous solution was investigated. Then, in the in-vivo stage, three probiotic strains that had the highest biosorption efficiency in the previously stage were selected and their effect with a ratio of 1:1:1 and contact time of 15 and 30 minutes on the removal of these toxic metals in coriander, leek and parsley fresh vegetables was evaluated. The residual concentrations of heavy metals in solution were measured by Inductively Coupled Plasma Mass Spectrometer (ICP-MS; ELAN DRC-e, PerkinElmer SCIEX, Canada) and Morphology of bacteria cell surfaces incubated with metals were monitored by scanning electron microscopy (JEOL JSM 5400 LV, Japan). Results and DiscussionThe results of the in vitro stage showed that the most ability to heavy metals adsorption was related to the Ent. Facium bacterium which were equal to 79.75±0.11, 75.28±0.05 and 83.99±0.10% for Pb, Cd and Ni, respectively. In general, the removal efficiency of heavy metals by LAB bacteria in the inactive and killed state was significantly higher than the active removal efficiency of these bacteria, so that the highest percentage of passive absorption of lead, cadmium and nickel metals by inactive strains of L. casei, L. plantarum and Ent. Facium were 90.01, 81.98 and 86.56%, respectively. Electron microscopy observations and energy dispersive X-ray (EDX) analysis confirmed that the majority of these toxic metals significantly damage the surface of living cells by accumulating and binding on the surface of bacterial cells. A combination of three bacterial strains had a synergistic effect on the binding properties of toxic metals compared to the single state of these bacteria, so that in both active and inactive states, 90-99% of heavy metals from edible leafy vegetables were removed in less than 15 minutes. The results of this research generally showed that the binding capacity of dead biomass is significantly high and it is possible to dispose and reuse biomass in case of biological absorption.
Research Article
Food Technology
Rezvan Shaddel; Shadi Rajabi Moghaddam
Abstract
Introduction
Caffeine is one of the most common bioactive compounds in the world that can enhance mental and physical performance However its bitter taste has created challenges for the use of this compound in food. Nano-encapsulation technology, such as the use of liposomes, is one of the simplest ...
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Introduction
Caffeine is one of the most common bioactive compounds in the world that can enhance mental and physical performance However its bitter taste has created challenges for the use of this compound in food. Nano-encapsulation technology, such as the use of liposomes, is one of the simplest ways to overcome this issue. In this research, caffeine was encapsulated in nanoliposomes coated with chitosan and then the drink powder enriched with caffeine nanochitosome was produced.
Materials and methods
In this research, pure caffeine powder was purchased and stored in dry environment at room temperature. Ethanol (96%) and acetic acid were obtained from Mojallali Company, Tween 80 from Merck Company (Germany), lecithin (P3556), cholesterol (C8667), and chitosan (medium molecular weight) purchased from Sigma Aldrich Company (Germany). Sugar, essential oil and citric acid used in the formulation of the drink were purchased from a local store.
First, nanochitosomes in ratios of 9:1, 8:2 and 7:3 lecithin-cholesterol, were prepared using thin-layer hydration method. Then, the particle size and zeta potential were measured to determine the characteristics of the produced particles. Encapsulation efficiency was measured for 9:1, 8:2 and 7:3 lecithin-cholesterol ratios. The stability of the chitosomal sample with a ratio of 9:1 lecithin-cholesterol was evaluated through visual observation of precipitation formation and the amount of release of encapsulated caffeine during 60 days of storage at ambient temperature was calculated. FTIR was performed for each of the components of the wall of chitosomes, caffeine powder, chitosomal solution containing caffeine and chitosomal solution without caffeine with a ratio of 9:1 lecithin-cholesterol. Nanochitosomes with 9:1 lecithin-cholesterol ratio were used in the formulation of beverages due to having the smallest particle size, favorable zeta potential, the highest microencapsulation efficiency, and high stability during storage. The drink samples were prepared in different formulations (samples containing 3 and 5% free caffeine solution, samples containing 3 and 5% chitosomal caffeine solution and the control sample). Then, the drinks were evaluated in terms of sensory characteristics and other physico-chemical characteristics (pH, acidity, Brix degree, etc.). The drinks produced were turned into powder with a freeze-dryer machine, and two important characteristics of powdered products, i.e. water solubility index and their hygroscopicity, were evaluated.
Results and Discussion
The average particle size and zeta potential for different ratios of lecithin -cholesterol were obtained in the range of 133.3-443.6 nm and +40.96 to +48.36, respectively. The encapsulation efficiency for 9:1, 8:2 and 7:3 lecithin-cholesterol ratios were 91.2%, 86.18% and 79.09 %, respectively. The chitosomal sample with 9:1 lecithin-cholesterol ratio showed good stability during 60 days of storage at ambient temperature. FTIR results showed that caffeine was loaded in nanochitosomes. The results of the sensory evaluation of the prepared beverages showed the acceptability of the taste of the samples containing caffeine nanochitosome compared to the samples containing free caffeine, which indicates the success of chitosomal nanocarriers in covering the bitter taste of caffeine. The results of measuring the color of different drink samples showed that there is no significant difference between the color of samples. The results of measuring pH and acidity did not show significant differences between different drink samples. The results of measuring the solubility of different drink powder samples showed that the samples containing caffeine nanochitosomes have low solubility compared to other drink powder samples. Also, the hygroscopic amount of the drink powder containing caffeine nanochitosomes was lower than the other samples, which is considered as an advantage for powdered products.
The results obtained in this research showed that nanochitosomes are an efficient system in covering the bitter taste of caffeine. Therefore, with the production of caffeine nanochitosomes and its usage in the formulation of powder drinks, it is possible to produce energizing and desirable drinks without the need to use high amounts of sucrose.
Research Article
Food Technology
Yazdan Moradi; Mansoreh Ghaeni; Haleh Hadaegh
Abstract
Introduction
Seaweeds contain a high amount of protein, essential amino acids, vitamins, minerals, unsaturated fatty acids such as arachidonic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), natural pigments, macro and micro nutrient compounds. Microalgae Spirulina (Spirulina ...
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Introduction
Seaweeds contain a high amount of protein, essential amino acids, vitamins, minerals, unsaturated fatty acids such as arachidonic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), natural pigments, macro and micro nutrient compounds. Microalgae Spirulina (Spirulina platensis) is a species with high nutritional value. About 60% to 70% of the dry weight (Spirulina platensis) is protein, which has all the essential amino acids. This is a cyanobacterial microalga that is cultivated all over the world and used as a supplement in the human diet in the form of tablets, powder and cookies, bread, salad and soup. Several studies have been conducted in the field of investigating the effect of microalgae addition in food products. The purpose of the current research was to investigate the effect of this microalgae powder on sensory, physical, protein and iron properties of three different products of bulk bread, cake and layered sweets with different formulations.
Materials and Methods
Spirulina microalgae dry powder in 0.25%, 0.5%, 0.75%, 1% and 1.25% was added to the formula of three products: bulk bread, layered pastry, and cake. From each product, a sample without microalgae powder was also prepared and considered as a control. The treatments were evaluated in terms of sensory, color, texture, protein and iron content. Sensory evaluation was carried out by 30 panelists using 7 hedonic points to evaluate the color, flavor, texture, smell and overall acceptance. The color of the surface of the samples was done with a Minolta Chroma Meter (CR-300 Minolta Japan). The results calculated based on L* (whiteness/darkness), a*(redness/greenness) and b*(blueness/yellowness). Hardness of samples was measured with Texture Analyzer TA-XT2 (Stable Micro Systems, Surrey, England) and P/0.5 cylindrical probe (12.5 mm diameter) with 30 kg load cell. Protein of the samples was measured by Kjeldahl method and the amount of iron was measured according to the standard method of AOAC 999.11. All analyses were performed in three repetitions and one-way ANOVA and Tukey's test were used to compare the means.
Results and Discussion
The results showed that the behavior of spirulina microalgae in changing the characteristics of the three products is different, and this difference is especially significant in sensory characteristics. The addition of spirulina microalgae increased the amount of protein and iron in different treatments. This increase for protein in bread, cake and sweets was about 1, 0.6 and 1.2 percent, respectively. Also, the amount of iron in treatments containing microalgae in bread, cake, and layered sweets was 4, 5, and 3 mg/kg, respectively. Spirulina microalgae is basically known as an aquatic plant with high protein and iron. The microalgae used in this research contained a high amount of protein (67.97%) and 29.5 mg/100 grams of iron, so adding this microalga to the samples increased the amount of protein and iron. Sensory evaluation of the samples showed that all three products had an acceptable acceptance score. However, in comparison among the three products of bread, cake and layered sweets, bread had a lower score than the other two products. The instrumental analysis of L*, a*, b* color indices showed that the increase of spirulina caused green color in the treatments and this color change is more significant in the bread sample. Also, the results of texture analysis showed that the addition of spirulina reduces the hardness of samples containing spirulina. It can be concluded that spirulina microalgae can be used to improve texture, color, and also increase the amount of protein and iron in products.
Review Article
Food Technology
Bahareh Nowruzi
Abstract
Introduction
Intelligent food packaging as a new technology can maintain the quality and safety of food during its shelf life. This technology uses indicators and sensors that are used in packaging and detects physiological changes in food (due to microbial and chemical degradation). These indicators ...
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Introduction
Intelligent food packaging as a new technology can maintain the quality and safety of food during its shelf life. This technology uses indicators and sensors that are used in packaging and detects physiological changes in food (due to microbial and chemical degradation). These indicators usually provide information that can be easily identified by the food distributor and the consumer. However, most of the markers currently used are non-renewable and non-degradable synthetic materials. Microalgae that live in both marine and freshwater are a versatile solution for building new biosensors to detect pollutants such as herbicides or heavy metals. These photosynthetic microorganisms are very sensitive to their environmental changes and allow the detection of pollutants. In the past few years, several studies have been conducted in relation to the development, evaluation and application of biosensors using natural compounds in smart food packaging, and some of them are reported and summarized in Table 2.
Materials and Methods
In these studies, examples are mainly focused on biosensors related to biopolymers, but some other synthetic polymers that are easily degraded have also been used as examples. In Table 2, it is also specified what the function and application of the sensor is and how it reacts to the loss of freshness of food. Most sensors are sensitive to the change in pH caused by the release of volatile nitrogen compounds, and this change is characterized by a colorimetric response. Sensors are usually placed in the space above the food container, avoiding direct contact with the food, but close enough to detect changes in the environment and respond to changes in food quality. When these biosensors are integrated with biopolymers, they are usually incorporated into the polymer structure, and the color change of the layers (film) indicates changes in food quality in the packed product. The collected information also clearly shows that extracts rich in chemical compounds of pigments that change color with pH and especially anthocyanins have been used in these biosensors. In addition, most studies of biosensors have been conducted on fish, meat, and seafood, which is probably because their quality degradation is an important economic loss and also because the pH of the surrounding environment is changed during the degradation process. , and this change is easily detected through pH-sensitive biosensors. Smart food packaging technology has made it possible to monitor food quality by incorporating markers, sensors and radio frequency identification (RFID) into packaging. The technology also allows producers and consumers to trace the history of a product through important points in the food supply chain.Interestingly, some compounds applied and tested in the sensor not only provide a pH-sensitive dye, but also have other bioactive properties, for example, antimicrobial properties, and its presence in the polymer matrix can also increase the storage activity of packaging materials.
Results and Discussion
This paper shows that microalgae can be used as biosensors to detect pollutants such as herbicides, heavy metals and volatile organic compounds. These biosensors are very sensitive and reproducible for physical or chemical analysis. One of the main advantages of these microalgal biosensors is that repeated measurements can be performed without extensive sample preparation. They can also be selective, for example chlorophyll fluorescence emitted from photosynthetic activity allows the detection of herbicides, while inhibition of alkaline phosphatase and esterase allows the determination of heavy metals and organophosphate insecticides. Recently, great progress has been made in the identification of genes and related pathways in microalgae, and powerful techniques for genetic engineering have been developed. Collectively, the progress achieved in these areas will rapidly increase our ability to genetically optimize the production of more sensitive microalgae-based biosensors.
