Food Technology
Ebrahim Taghizadeh; Mohammad Alizadeh khaled abad; Hamed Hassanzadeh
Abstract
IntroductionEdible films and coatings are suitable for fresh, semi-processed foods, and also for processed fruits and vegetables because they can increase their shelf life, protect them from the activity of microorganisms, and ultimately improve their nutritional and sensory value. In addition, edible ...
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IntroductionEdible films and coatings are suitable for fresh, semi-processed foods, and also for processed fruits and vegetables because they can increase their shelf life, protect them from the activity of microorganisms, and ultimately improve their nutritional and sensory value. In addition, edible films and coatings are able to transfer compounds that may have been added to improve the performance of the coating film and better preserve the product or have benefits for the consumer. The present research was conducted with the aim of investigating the structural physicochemical properties of whey protein concentrate smart film containing pomegranate and red grape anthocyanins and zinc oxide nanoparticles. Material and MethodTo prepare nano composite film, 10 grams of whey protein concentrate powder was added to 90 ml of distilled water. At the beginning of the production of the film, the pH was adjusted to pH = 8 with the help of 0.1 normal soda, and in order to better dissolve the isolate, the solution was heated for 30 minutes at 80 degrees Celsius to ensure denaturation. It was then placed on a magnetic stirrer. After cooling the solution, pomegranate and red grape anthocyanins were added to the solution separately according to the statistical plan. The solution was then homogenized for 10 minutes at 13,000 rpm, and finally zinc oxide nanoparticles were added to the solution according to the statistical plan and homogenized on a magnetic stirrer for 10 minutes, and then in an ultrasound bath to disperse for 10 minutes In the next step, glycerol was added to the 40% of the weight of the dry substance and placed on a rotating magnetic stirrer without heat for 15 minutes. The formed solution was aerated for 10 minutes and 25 ml of it was poured in the center of the plate (8 cm). Then the film was dried in the oven at 38 degrees Celsius and the control film was produced. After preparing the films, the color of the film samples was determined by measuring the color components L* (lightness), a* (red/green) and b* (yellow/blue) using a Hanterlab colorimeter. The thickness of the films was measured by a digital micrometer with an accuracy of 0.001 mm at 10 random points of each film. Finally, humidity, solubility and FTIR measurement tests were also performed for the prepared films. The preparation of whey protein concentrate smart composite film was investigated based on two variables: red grape anthocyanin/pomegranate anthocyanin percentage and copper oxide nanoparticle percentage. Each of which was investigated in five levels and the response surface methodology (RSM) of the central composite design was used. A total of 24 composite films were prepared and their physical and chemical properties were investigated. Also, after analyzing the data, the optimal movies were checked based on optimization and utility function by 11 Design expert statistical software. Results and DiscussionBy increasing the amount of anthocyanin and zinc oxide nanoparticles, the thickness of the layers increased up to the middle point (0.58-0.89 mm), and the largest increase in thickness was observed in samples with 1.5 cc of anthocyanin and 2% of zinc oxide nanoparticles. Also, films with low concentrations of anthocyanin (0.1-4 cc) and a high percentage of the selected range of zinc oxide (0.2-0.7%) show the highest percentage of solubility. The added zinc oxide nanoparticles increased the solubility of the films. FTIR analysis showed that the interactions between whey concentrate and anthocyanins were probably responsible for the changes in the properties of the composite layers. The utility function for each response was estimated by numerical methods and the general utility function was obtained for the optimal samples of red grape and pomegranate. For the optimal pomegranate, the obtained results include the amount of anthocyanin equal to 2.6 cc, zinc oxide nanoparticles 0.6 (weight/volume), solubility 65.37, thickness 0.64 mm, indices a, L and bwere. 27.88 0.24 and -2.01, respectively. Finally its total desirability has been reported as 0.58. The utility function for each answer was estimated by numerical methods and the general utility function was obtained for the optimal samples of red grapes such as the optimal pomegranate. For the optimal grape film samples, the obtained results include: the amount of anthocyanin equal to 1.38 cc, 3.4 zinc oxide nanoparticles (weight/volume), solubility 59.83%, thickness 0.83 mm, a, L and b indices were 27.03, 7.05 and 1.92 respectively and, its total desirability was 0.63.
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.
Food Technology
Khadije Sadat Tabatabae; Mohammad Fazel
Abstract
Introduction: Nowadays, lack of time and busy work schedules have led to increase the demand for ready-to-eat foods. Furthermore, as cardiovascular diseases are on the rise in the world including our country, with nearly 40 percent of deaths being linked to these diseases, there is a growing demand for ...
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Introduction: Nowadays, lack of time and busy work schedules have led to increase the demand for ready-to-eat foods. Furthermore, as cardiovascular diseases are on the rise in the world including our country, with nearly 40 percent of deaths being linked to these diseases, there is a growing demand for low-fat products. The main purpose of the deep frying process is to preserve the aroma and flavor of the ingredients in a crispy crust by immersing the food in hot oil. Frying at high temperatures affects the transfer of mass and heat, which causes some of the water to evaporate and be removed from the product, and the oil is moved into the product, replacing the extracted water. This study aims to use methods that reduce the absorption of oil in the fried product, which can reduce health concerns and increase consumer acceptance of the product. Materials and methods: In this study, a day-old chicken breast fillets were used to prepare the samples. The weight of the samples was between 14.5 and 15 grams, with a diameter of 3.7. Coating solutions include aloe vera gel powder at three levels of 1.5, 3, and 4.5 % (w / v) and whey protein concentrate (WPC) at three levels of 2.5, 5 and 7.5 % (w / v), made with distilled water at 25C. Baguette bread was also used to make breadcrumbs. To coat the chicken breast fillet, the samples were immersed in the coating solution (control samples in distilled water) for 1 minute and then placed in breadcrumbs. After preparation, the samples were fried in an automatic fryer at a controllable temperature of 140 C for 6, 8, and 10 minutes, then the samples were cooled to room temperature for 10 minutes and tested for physicochemical properties. The tests included coating, weight loss, moisture content according to the standard AACC method, adsorption of oil by standard method AOAC, tissue measurement test based on the stiffness of the chicken tissue cutting (catching test), and color analysis of chicken samples using CIE Lab colorimetric system through the determination of color characteristics were performed. Results & discussion: The results showed that the coated samples increased the absorption of the coating glaze due to the increasethe viscosity and thus the absorption of baking powder compared to the non-coated sample. The coating with hydrochloric materials based on barrier properties through strong hydrogen bonds between water molecules forms a gel layer with a high water holding capacity that prevents moisture from escaping. This subsequently reduces weight loss. Moreover, due to the inverse relationship between water and oil content, oil absorption was significantly decreased (p<0.01). Among the studied coatings, the highest moisture retention rate and the lowest oil absorption rate are related to the coated sample with 4.5% aloe vera and 7.5% WPC. As the concentration of aloe vera increased, the hardness of the samples decreased, which may depends on the effect of the meat protein to polysaccharide ratio. As the concentration of WPC increased, the stiffness of the samples increased, increasing the sulfhydryl groups, increasing the disulfide bonds in the meat's myofibrillar protein, and thus increasing the tissue stiffness. Increasing the frying time reduced the moisture and increased the oil absorption, weight loss, and stiffness of the samples. The coating reduces brightness due to the presence of various phenolic pigments, especially light- and heat-sensitive anthraquinones in aloe vera and lactose in WPC, and Maillard's reaction at high processing temperatures, resulting in increased browning index and darkening with increasing product color time. This is correlated with the Maillard reaction. Coating with aloe vera gel and WPC is effective in improving the physicochemical properties of fried chicken.
Food Engineering
Hossein Mohebodini; Atefe Maqsoudlou
Abstract
Introduction: Microencapsulation is the most commonly used method of preserving proteins and peptides, which increases the stability in different conditions. Bee pollen with 10–40% protein, is a valuable source of protein that has functional and nutraceutical properties. By hydrolysis and producing ...
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Introduction: Microencapsulation is the most commonly used method of preserving proteins and peptides, which increases the stability in different conditions. Bee pollen with 10–40% protein, is a valuable source of protein that has functional and nutraceutical properties. By hydrolysis and producing bioactive peptides, their functional and health effects will be improved. Fibersol is a dietary fiber that can be used in many foods and supplements. This carbohydrate compound is actually non-digestible maltodextrin and has recently been used as a wall material in encapsulation. Few studies have conducted on the microencapsulation of hydrolysed proteins and their stability during accelerated conditions. On the other hand, by-products of honey bees such as pollen have been less noticed; therefore the aim of this study was the microencapsulation of bioactive bee pollen protein hydrolysate by fibersol and WPC and to study the changes of structure and stability of resulted microcapsules during the exposure to UV radiation. Material and Methods: Bee pollen was hydrolysed by Alcalase (1.5%) for 4 h in shaking incubator. The protein hydrolysate was microencapsulated using WPC, fibersol, and their combination by spray drying. The wall materials and hydrolysed protein were used in ratio of 10:1 (w/w). WPC 2%, fibersol 2%, as well as WPC and fibersol mixtures with 1:3 ratio, were the wall materials. For accelerating the oxidation reactions, the obtained capsules were exposed to UV radiation for 48 h. During the exposure to UV radiation, the DPPH radical scavenging activity of microcapsules and hydrolysed protein was measured. Interactions between hydrolysed protein compounds, WPC and fibersol were identified by the FTIR spectroscopy. The SEM was used to investigate the morphology of the microcapsules. Results & Discussions: Almost at all experimental time, the highest DPPH radical scavenging during exposure to UV radiation was related to the capsules prepared using fibersol and WPC mixture and after that the capsule with WPC as wall material. The FTIR spectroscopy of the hydrolysed protein was changed significantly when it was exposed to UV radiation. This change caused by losing the hydrogen bonds in the secondary structure of proteins, including the separation of two polypeptide chains or the opening of the αhelix and loss of β-sheet structure. The FTIR profile of capsulated hydrolysed protein by fibersol showed that the adhesion of protein and polysaccharide changed the absorbance of C–H bending and N–H stretching bands of amide groups in the hydrolysed protein in 3000–3500 cm-1 and the stretching band of C–H and O–H group in the region of 2000–3000 cm-1 for fibersol in the wall. After exposure to UV, because of cross-linking in fibersol and more involving the molecules of fibersol to protein, the absorbance was increased in the region of 1500–3500 cm-1. The number of peaks and absorbance in the FTIR spectra of hydrolysed proteins microencapsulated in WPC were more than number of peaks and absorbance in the FTIR spectra of WPC. There was no significant difference in the FTIR spectra of hydrolysed protein encapsulated with WPC before and after exposure to UV. The peaks in FTIR spectra of hydrolysed protein microencapsulated with the mixture of WPC and fibersol, showed higher absorbance level than the peaks of fibersol and lower than peaks of WPC. None of the peaks of microencapsuls with the wall of mixture of WPC and fibersol, were changed after exposure to UV radiation. Results of SEM showed that the microcapsules prepared with mix of fibersol and WPC had a uniform and smoother wall than microcapsules prepared with only fibersol. Finally, the mix of WPC and fibersol was selected as the best wall with a proper protective ability for the microencapsulation of hydrolysed proteins and protection against UV radiation.
Samaneh Joodi Attar; Vahid Hakimzadeh; Hassan Rashidi
Abstract
Introduction: Cheese is a dairy product that commonly used and has lots of variety in the world. Among the various types of cheese, UF cheese is attracting more consumers in Iran. The need to change the flavor and make a diversity in this product has been considered for long time. Since high fat foods ...
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Introduction: Cheese is a dairy product that commonly used and has lots of variety in the world. Among the various types of cheese, UF cheese is attracting more consumers in Iran. The need to change the flavor and make a diversity in this product has been considered for long time. Since high fat foods such as cheese are the main cause of some disorders like cordial disease, cancer, obesity and diabetes, formulation of dairy products with modified fat or fat replacer was considered by many researchers and suppliers. Vegetable oils can be used as a substitute for milk fat in cheese. Flaxseed oil consists high level of alfa-linolenic acids (Omega-3) and suitable amount of proteins could noticed as a fat replacer. In this study, we investigated the effect of milk fat replacement with flaxseed oil on the production of functional Feta cheese. The rheological, physicochemical, and organoleptic characteristics of such cheese and its optimal formulation were also determined
Materials and methods: The effect of Flaxseed oil (FSO) at a range of 0-100 % and whey protein concentrate (WPC) (0-15%) was investigated on pH, synersis, Dry Matter, hardness, springiness as physicochemical and mechanical properties and mouth feeling, odor, taste overall acceptance as organoleptic properties of UF cheese production by RSM. For the preparation of cheese, a free fat retentate powder was used. To adjust fat to 20%, cream was used with 70% flaxseed oil and homogenized by ultraturrax method. All of the physicochemical, mechanical and organoleptic tests accomplished according to theIranian national Standards/
Results and discussions: Results showed that by increasing the amount of FSO in the formulation of cheese, pH, stiffness and synersis increased. Also, with increasing flaxseed oil, the elasticity was initially decreased and increased in greater quantities afterward. However, by increasing the WPC, the elasticity decreased. The increase of flaxseed oil had a reversible effect on the taste, smell, color and overall cheese acceptance score compared with the control samples due to the presence of some impurities in oil. Increasing the amount of WPC and FSO also caused a decrease in pH and fat during ripening of cheese. Although increasing the level of WPC improved the odor of cheese, but did not have positive effect on appearance, color and general acceptance. The result of optimization of UF cheese production with the following indices: pH 4.82%, synersis 1.35%, fat 20.3%, dry matter 32.45%, hardness 631.46 nm, elasticity 0.94 mm, color 3.4, Odor 3.1, flavor 2.8, texture 3.1 and final acceptance 3.11, showed that the best formulation needs 96.01% of flaxseed oil and 9.73% whey protein concentrate. Finally, the predicted optimal formula by software was also determined as follow: pH 4.78, synersis 1.27%, fat content 19.8%, dry matter 31.4%, the firmness index 618.02, the elasticity 1.03 mm, and the sensory scores included color 3.4 , odor 3.15, Taste 2.97, Texture 3.64 and Final acceptance 3.21.
Aliakbar Gholamhosseinpour; Mostafa Mazaheri Tehrani; Seyed Mohammad Ali Razavi
Abstract
In this study, a mixture of milk protein concentrate, whey protein concentrate, skim milk powder, soymilk, margarine, butter and water was used for production of recombined UF-Feta cheese analogue. Variables were milk protein concentrate (8%, 9%, 10%), whey protein concentrate (0%, 1.5%, 3%), soymilk ...
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In this study, a mixture of milk protein concentrate, whey protein concentrate, skim milk powder, soymilk, margarine, butter and water was used for production of recombined UF-Feta cheese analogue. Variables were milk protein concentrate (8%, 9%, 10%), whey protein concentrate (0%, 1.5%, 3%), soymilk (5%, 10%, 15%) and margarine (0%, 5%, 10%). Textural properties of Samples were analyzed 3 days post-manufacture. The central composite design was employed and the results were modeled and analyzed using response surface methodology. Coefficients of determination, R2, of fitted regression models for different variables were varied in the range of 89.59-97.80 and the lack-of-fit was not significant for all responses at 95%. Hence, the models for all the response variables were highly adequate. The results showed that the optimum processing conditions for producing cheese with suitable hardness and cohesiveness and lowest adhesiveness were: 9.13% milk protein concentrate, 3% whey protein concentrate, 15% soymilk and 7.65% margarine.
Malahat Safavi; Majid Javanmard
Abstract
In this study, the effects of coating with whey protein concentrate (7.5% w/v) alone and/or in combination with rice bran oil (0.2, 0.4, 0.6 g in 100 ml coating solution) and Zataria multiflora extract (1 and 2 μL in 100 ml coating solution) on the quality attributes and egg shelf life were carefully ...
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In this study, the effects of coating with whey protein concentrate (7.5% w/v) alone and/or in combination with rice bran oil (0.2, 0.4, 0.6 g in 100 ml coating solution) and Zataria multiflora extract (1 and 2 μL in 100 ml coating solution) on the quality attributes and egg shelf life were carefully observed and analyzed. Weight loss, Haugh index, yolk index, pH, air cell depth, shell strength and the impact of this coating on the microbial load of the eggs surface were studied at the end of each week (during the 4 weeks of storage in a room environment temperature and humidity). After 4 weeks of storage, it was observed that the weight loss in all of the treated eggs with whey protein concentrate and 0.2 gr of rice bran oil (experimental group) was significantly lower than that of the control group(P<0/05). With regard to Haugh index and yolk index, egg shelf life increased about 4 weeks compared with the control samples. Haugh Index changes revealed that the coated samples remained at grade A after 3 weeks of storage, while the control samples were relegated from grade AA to B after one week. Haugh and yolk Indices in all coated eggs were more than those of the control group. In the coated groups, Haugh and yolk indices of the coated samples with whey protein concentrate and 0.2 g rice bran oil and with whey protein concentrate and 0.2g of rice bran oil and 1 micro liter of Zataria multiflora extract were more than those of the other coated eggs and the control group eggs. PH values of the control group were higher than those of the coated groups during the storage of the eggs. The shell strength of the coated group was more than that of the control group (uncoated) and in coated samples, whey protein concentrate and 0.2 gr of rice bran oil coated samples had high shell strength. In the other treatments no significant differences were observed. The depth of the air cell of the coated groups was determined to be less than that of the control group during the storage period. The minimum inhibitory concentration was 1 μL of Zataria multiflora extract. The results showed that 1 μL concentration of Zataria multiflora extract reduces the microbial load of the egg shell surface to 87% and 2 μL reduced total bacterial load to zero. In sensory evaluation, from evaluator point of view, the coated eggs had more overall acceptance than the uncoated group (control), and in the treatment group coated eggs, those containing a low percentage of rice bran oil had higher overall acceptability. In conclusion, coating as a practical and cost effective method can maintain the quality parameters of eggs and lead to durability of supply conditions in addition to the product marketability.
Sanaz Ojnordi; Majid Javanmard; Simin Asadollahi
Abstract
Due to environmental risks generated by application of non-degradable and synthetic films, many researches have shown increasing tendency to edible coatings for storing food such as fruits and vegetables. Whey protein is considered one of the most common sources of edible coatings and its use has been ...
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Due to environmental risks generated by application of non-degradable and synthetic films, many researches have shown increasing tendency to edible coatings for storing food such as fruits and vegetables. Whey protein is considered one of the most common sources of edible coatings and its use has been studied in the current research. In this paper, the simultaneous effect of coating with whey protein and Zataria multiflora Boiss extract on the quality of peach kept in refrigerator has been studied. According to response surface methodology, were measured 20 treatments repeating 6 times in the center point and effects of the three factors including whey protein (2. 5 to 5 gr), Zataria multiflora Bioss extract (0 to 500 μL) and glycerol (0. 375 to 2. 25 gr) on the physicochemical characteristics, fungal decay and organoleptic traits of peach, were investigated in the condition 5±2 ̊C and 80% relative humidity during 21 days of storage. According to the results, by increasing Zataria multiflora Bioss extract concentration and whey protein of the coating, microbial decay and weight loss of the fruit was reduced and texture and soluble solids were conserved. Peel colour changes of the coated fruit was not significant compare to control and the coated samples had a light and bright colour. Coating peach resulted in natural ripening of the fruit and the coated fruits were softer and juicier than the fruits without any coating. The coating formulations had significant effect on TSS and TA. Optimized points of variables for achieving a coating with the maximum effect on shelf life improvement of peach (Prunus Persica cv. Anjiri) are: whey protein 4. 7475 gr, Zataria multiflora Bioss extract 498. 00 μL and glycerol 0. 6212 gr.
