ELECTRONIC JOURNAL OF FOOD PROCESSING AND PRESERVATION
Year:2018 | Volume:10 | Issue:1|Papers Count:8

Background and objectives: CoQ10 is a lipophylic natural antioxidant with fundamental role in mitochondria bioenergetics. The positive effect of CoQ10 in therapy of many diseases is attributed to its antioxidant and bioenergetics properties. Reduction of endogenous synthesis of CoQ10 by the ageing, insufficient amount in the food and several health benefits of CoQ10 have led to food fortification. The objective of this study was to microencapsulate CoQ10 by complex coacervation method and determinate of optimum mixture component (β-lactoglobulin (β-lg), Arabic Gum (AG), Oil containing CoQ10 and water) to achieve maximum value of microencapsulation efficiency (ME) and payload. Due to temperature sensitive characteristic of CoQ10, Gelatin was replaced with β-lg and combination of β-lg and AG were used to microencapsulation of Oil containing CoQ10. Materials and methods: At first CoQ10 powder and olive oil were poured in opaque tube and stirred in incubator shaker for 24h. Then solutions of β-lg and GA were prepared at 1-4% (w/w), by dispersing the required amount of them in deionized water and microcapsules were formed by adding oil phase containing CoQ10 to the β-lg solution and preparation of emulsion, adding the GA solution and adjusting pH to 4. After separation of microcapsules freeze dryer was used to dehydration of them, and Morphology of CoQ10 microcapsules was examined using a Scanning Electron Microscope (SEM) and an optical microscope. The particle size and the particle size distribution of moist microcapsules were determined using a particle size analyzer. In the next stage it was used from n-hexane to extracting oil and extracted oil was dissolved in 1, 4-dioxane and analyzed by a high performance liquid chromatography (HPLC) system, and microencapsulation efficiency was calculated for microcapsules before and after freeze drying. At the end the effect of oven drying and defrost on microencapsulation efficiency was studied for 5 formulations. Results: ME values before drying for all formulations except one sample (containing: 4%β-lg, 4%AG, 5%Oil and 87% water) were in the range of 94. 05-99. 01%. Variation in ME and payload values after freeze drying was in the range of 34. 91-92. 45 and 24. 78-83. 75%, respectively and sample containing 2. 5% (w/w) β-lg and 2. 5% (w/w) AG and 5 % (w/w) oil obtained the highest ME value, an homogeneous particle size distribution and had a smooth and free of pores surface. Conclusion: Based on the results, formulation containing 2. 5% (w/w) β-lg and AG and 5 % (w/w) oil can be successfully used to microencapsulation of CoQ10.

Background and objective: Sponge cake as a snack food has great popularity among individuals. It seems by fortifying its formulation as a popular snack food, can prepare a functional and nutritive formulation. On the other hand, with increase in sensitivity to gluten and celiac disease, demanding for gluten free or gluten reduced has increased. Due to the importance of proteins forming the viscoelastic gluten network products in creating of desirable rheological characteristics of bakery product, the necessity of using proteins with similar characteristics to replace the gluten proteins is inevitable. The aim of this study was to prepare a functional and nutritive product by using rice flour and wheat germ flour as substitute of wheat flour in sponge cake formulation. The cake batter samples were prepared based on 100 percent rice flour, also, wheat germ flour were used at levels of 0, 5, 10, 15, and 20 percent in batter formulations. Also, one sample containing wheat flour was prepared as control. Due to important role of wheat protein in forming of texture of dough and cake, Impact of replacing wheat flour with rice flour and wheat germ flour on dough rheological properties of resulting cake was investigated. Materials and Methods: After defatted wheat germ flour, cake samples were prepared according to specified the preparation of formulations. To study the rheological behavior, stable rheological tests (flow behavior) and sweep tests (strain sweep and frequency sweep) on obtained dough were applied by using rheometer equipped with two parallel plates. Results: Results of flow behavior test indicated that all batter samples exhibited thixotropic shear thinning behavior under steady shear tests, which fitted by Power law model and the factors related to this model were specified in the samples. Also, it was observed that batters exhibited weak-gel like properties, by using dynamic oscillatory shear tests and had significant effects on acquired parameters from frequency sweep test, such as storage modulus, loss modulus and tan delta (P<0. 05). Sample containing rice flour exhibited weak rheological characteristics compared with control. However, with increasing wheat germ flour levels (from 10 percent to 20 percent), viscosity and consistency coefficient increased, and the combination of rice flour and 10% wheat germ flour was closest to the control. Conclusion: It can be concluded, this is possible to prepare a functional product with desirable rheological characteristics by applying appropriate levels of rice flour and wheat germ flour as wheat flour substitutes in sponge cake formulation.

Background and objectives: Chitosan-based Biopolymer films have been widely studied to be used as a substitute for plastic polymers. Because of their hydrophilic nature, such polysaccharide films show poor mechanical properties in the moist condition that limits its application. Incorporating nano-materials into the basic biopolymer, known as nano-composite films, is one of the promising methods to improve physico-mechanical properties and water permeability of biopolymer-based films. In this research, the effect of different ratios of bentonite nanoclay/chitosan on the water vapor permeability (WVP), mechanical properties, and surface microstructure of the chitosan nanocomposite films was evaluated. Materials and methods: At first, different aqueous solutions of Chitosan biopolymer (2 and 3% w/v) and bentonite nanoclay (1 and 3% of chitosan weight) were prepared, separately. The chitosan solution was then slowly added to the clay suspension at 55 oC. The nanocomposite films were prepared using the solvent-casting method. Control samples with 2 and 3% chitosan were also prepared. WVP, tensile strength (TS), elongation at break (E), and microstructures of the final films were investigated. Results: The results showed that bentonite nanoclay had a significant effect (p<0. 01) on WVP and TS of chitosan nanocomposite films. By adding 1% nanoclay bentonite to the polymer matrix, TS increased to 0. 66 MPa (2% chitosan) and 0. 35 MPa (3% chitosan). Moreover, the elongation value decreased to 8. 8% and 6. 47% in the nanocomposite films with 2 and 3% chitosan, respectively. When clay content increased to 3 wt % in chitosan (2 wt%) nanocomposites film, WVP, elongation and TS decreased. According to the SEM micrograph, non-homogeneous structure was found for 1% clay-chitosan nanocomposite in comparison to the control sample. By increasing the concentration of nanoclay bentonite to 3%, the pore size of resulting film increased which was followed by a decrease in TS. Conclusion: According to the findings of this research, it can be concluded that addition of bentonite nanoclay would improve mechanical, morphological, and WVP properties of chitosan-based film.

Background and objectives: Cream cheese is prepared from pasteurized milk and cream that is characterized by a soft and smooth texture. The high fat contents in some dairy products like cream cheese may be harmful for some consumers. Therefore, demand is increasing for low fat and low calorie dairy products. On the other hand, fat has not only nutritional role, but also a crucial role in the cheese texture and appearance. Low-fat cheeses have disadvantages such as poor taste and texture, therefore in this study, the effects of addition of microbial transglutaminase and gelatin on the texture (hardness, cohesiveness, resistance and chewiness), viscosity and sensory properties (color, odour, taste, texture, overall acceptance) of low-fat cream cheese were evaluated. Materials and methods: Effects of gelatin at three concentration (0. 2, 0. 4 and 0. 6 %) and different concentrations of microbial transglutaminase (1, 3 and 5%) were investigated through measuring the textural, rheological and sensory properties using response surface methodology (RSM) and design expert software (V. 6. 0. 2). The experiment was conducted based on Box-Behnken design with three independent factors at three levels, in total comprising 13 run tests. Sensory evaluation was performed with Hedonic method. Rheological properties and texture analysis was done using the Texture Analyzer. All samples were produced in the same condition and stored at 4-6 ° C. Results: Cream cheese properties were assessed using response surface graphs, and secondorder polynomial models were obtained for each response. Since the coefficient of determination (R2) were higher than 0. 8, and lack of fit for all above characters were not significant (p 0. 05), the suggested regression models were found to be suitable for fitting the experimental fitting. Finally, the optimum point for the production of low-fat cream cheese was determined. Conclusion: According to optimization, it was found that transglutaminase concentration of 3. 01% and gelatin concentration of 0. 38%, led to a low-fat cream cheese with desirable rheological properties. Sensory evaluation revealed that the product manufactured at optimum point was also preferred by the panelists.

Background and objectives: Pumpkin is a good source of carotene, water-soluble vitamins and amino acids that can be processed into flour with a longer shelf-life. Pumpkin flour can be used because of its highly-desirable flavor, sweetness and deep yellow orange – red colour. Malting is a biotechnological process including steeping, germination and killing of cereals under controlled conditions, consequently, hydrolytic enzymes are activated and endosperm cell wall, protein and starch are largely digested. Cakes with desirable organoleptic characteristics is one the most commonly used cereal products all over the world. According to the role of dietary fiber on health and preventing some types of cancer and diabetes, high-fiber foods have gained much attention. Materials and methods: In this study, pumpkin and malt powders (at four different levels of 0, 10, 20 and 30 %) were used as substitute to wheat flour in the sponge cake formulation. The effects of this substitution on physicochemical and sensory properties of sponge cake including pH, fat, protein, moisture, ash, β-carotene, mineral, carbohydrate and texture were evaluated. Results: The results showed that no significant difference was observed for fat and protein contents of new formulated cakes with increasing pumpkin and malt powder. PH, fat and protein contents were in the ranges 6. 55-6. 85, 24. 34-27. 23 % and 8. 40-8. 75 %, respectively. However, moisture, ash and carbohydrate contents showed significant differences (P<0. 05) among different samples. By increasing the amounts of pumpkin and malt powder, significant difference was observed in β-carotene, calcium and iron contents in the final cakes ranging from 0. 40 to 1. 98 mg/100 gr, 500-700 mg/100, and 40. 75-59. 70 mg/100, respectively. Also, different textural properties were found among the different manufactured cakes as addition of pumpkin and malt powders resulted in softer sponge cake. Conclusion: Sensory evaluation of treatments showed that manufacturing sponge cake with 10% of pumpkin and malt powder was the best formulation.

Background and objectives: Soy has long been a great source of high quality vegetable proteins rich in lysine, which the most cereals are deficient, is known. The nutritional value of soybean increases by germination because of activation of plant enzymes which results in diminishing anti-nutritional factors and increasing digestibility of proteins and carbohydrates. The aim of this study is increasing the nutritional value of bread while maintaining or even improving its quality using germinated soy flour. Materials and methods: In this study, effect of adding germinated and non germinated soy flour at concentration of % 10 (based on flour weight) on dough properties and barbari bread quality was studied. After bread making; moisture content, symmetry index, dough properties such as: water absorption, dough development time, stability time, degree of softening and quality number were measured by a Farinograph. Results: The results of this study showed that adding germinated and non germinated soybean flour to bread formulation had no adverse effect on bread quality properties and even improved some characteristics. The results of moisture content analysis showed that bread crumb including germinated soy flour had the most moisture content and it was significantly different from bread including non germinated soy flour and control bread (P<0. 05). According to symmetry index, there was no significant difference between control bread and bread containing non germinated soy flour (P<0. 05). Bread sample with non-germinated soy had the highest symmetry index. Moreover, based on Farinograph results, both bread samples containing soy flour were better than control sample except for stability time factor, in which, significant difference was not seen between control bread and germinated soy bread. By the addition of germinated and non germinated soy flour to bread formulation, the microstructure of bread samples improved in comparison with that of control bread. According to sensory evaluation, there was no significant difference among samples except for color value. The bread sample containing germinated soy was significantly lower than the control bread and bread containing germinated soy flour based on color value. Conclusion: Totally, according to quality properties such as moisture content of dough and bread, symmetry index and microstructure, bread containing germinated soy was superior to non-germinated soy. But based on bread color and dough stability, the bread containing nongerminated was found to be better. According to these findings, adding soy flour to the bread formulation can be applied as an inexpensive way to improve the nutritional quality of the community.

Background and objectives: Oxidation is the main causes of oils and fats rancidity. Oil oxidation changes the organoleptic properties of food and also reduces nutrition value and shelf life of oils. Synthetic antioxidants such as TBHQ, BHT, BHA and GA are added to oils and fats to preventing off-flavour that occurs by oxidation. Due to the adverse effects of such synthetic antioxidants health including mutagenic and carcinogenic effects, production of natural antioxidant as alternative for synthetic antioxidants is necessary. The aim of this study was to evaluate the effects of extraction techniques on phenolic compounds and antioxidant activity of white mulberry leaves extract as natural antioxidant. Materials and Methods: The white mulberry leaves were dried and milled followed by different extraction techniques like maceration (ethanol solvent – water, 50: 50), ultrasound assisted and supercritical fluid extraction. Total phenolic compounds (TPC) and tocopherol (TC) were measured using Folin– Ciocalteu method and colorimetric assay and antioxidant activity of resulted extracts were measured using 1, 1-Diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging, and β-caroten/linoleic bleaching assays. Antioxidant activity of the extracts was compared with that synthetic antioxidant TBHQ. Results: The TPC and TC in ultrasonic extract were higher than those in other extracts. DPPH radical scavenging, and also in β-Caroten/linoleic acid assay, the activities of extracts were significantly concentration-dependent and more potent at higher extracts concentration. Free radical scavenging value varied from 40. 98% to 77. 46%. At all concentrations examined, samples from ultrasound-assisted extraction had the highest antioxidant activity and those from maceration extraction method showed the lowest activity. When extract concentration increased from 100 to 2000 ppm, antioxidant activity increased, while at 2000 ppm, the extracts activity was not statistically different from TBHQ (at 100 ppm). Conclusion: In overall, the results this of study indicated that the ultrasound-assisted extraction was more effective in obtaining mulberry leaf extracts with antioxidant activity. The high antioxidant activity of the extracts appeared to be attributed to its high tocopherol and phenolics contents. Therefore, white mulberry leaf extract may be used as a natural antioxidant to replace the synthetic antioxidants in food industry.

Background and objectives: Rice is a very popular cereal in world and very important from economic point of viwe. The problems of drying paddy rice is lack of drying uniformity in the paddy rice that creates stress temperature and moisture and thus will cause losses in the later stages. The purpose of this research was to develop a high performance system for processing the paddy to healthy white rice in the shortest drying time. Materials and methods: In this study, to reduce losses and increase the drying rate, an innovative laboratory rotary dryer machine was used. The response surface methodology (RSM) with central composite design was used for modeling and determinimg the optimum processing conditions for paddy drying. Independent variables for this process were temperature (40 to 80° C), cylinder rotation speed (2 to 10 rpm) and the cylinder fullness (25 to 66%). The percentage of breakage, percentage of crack and drying time were used as response parameters to develop predictive models and optimize the drying process. Results: The results showed that the temperature, cylinder rotation speed and cylinder fullness had significant effect (P<0. 01) on the percentage of breakage, percentage of crack and drying time, as temperature was the most effective parameter. According to optimization process, the minimum losses (percentage of breakage and percentage of crack) and drying time were found with the inlet air temperature 56. 53 ° C, cylinder rotation speed of 10 rpm and the cylinder fullness of 54. 20%. Conclusion: Conditions and parameters of drying process had important rule in the final quality properties and losses of paddy rice. Our results revealed that RSM could be used to develop adequate prediction models for describing quality changes in paddy rice during drying. The changes in the quality parameters were adequately described by quadratic model. Also, the result showed that inlet temperature was more important than cylinder rotation speed and cylinder fullness on losses of paddy rice.