مجله علوم غذایی و تغذیه
سال شانزدهم شماره 2 (بهار 1398)

  Apple is a rich source of fiber and polyphenols. To investigate the effect of replacing apple powder with wheat flour on viscoelastic properties of sponge cake, stress relaxation test was performed. First apple was dried in optimal conditions and milled, and then apple powder was used for enrichment of sponge cake at five levels of 0, 5, 10, 15 and 20 % (w/w) as substitute of wheat flour in the cake formulation. After preparing the samples, stress relaxation test was carried out using a texture analyzer during storage time and coefficients of the Peleg-Normand and the extended Maxwell models were calculated. The results showed that by increasing the substitution of apple powder and storage time, the initial force and balance force values were increased. The parameters of Peleg-Normand model include k1 and k2 decreased with time that indicated a reduced elasticity of the cake with the time. The cakes showed solid viscoelastic behavior and by increasing the replacement, total reduced forces (F1+F2+F3) of generalized Maxwell model are increased which indicates that the elasticity is reduced. The results of stress relaxation modeling of experimental data with Peleg-Normand and the extended Maxwell models showed that the extended Maxwell model is more efficient to evaluate the viscoelastic properties of rich sponge cake with apples powder.

Employing fat-replacers for development of low-fat food formulations is of growing interest because of consumers’ desire for healthy eating. The present study was aimed to investigate the possibility of using Zedo and almond gums as fat replacers for developing a vanilla low-fat dairy dessert. Effect of different levels of Zedo or almond gums (0.1, 0.2 & 0.3% w/w) on flow behavior and organoleptic characteristics of vanilla low-fat dairy dessert was studied in comparison to those of full-fat control sample. The flow behavior of the dairy desserts fitted well to the Ostwald de Waele model (R2>0.99). All the samples exhibited shear-thinning flow behavior; however, fat reduction significantly resulted in decreased apparent viscosity and consistency index and increased flow index. Zedo and almond gums both caused an increase in the consistency index and favored the shear-thinning behavior of the low-fat dairy dessert as the flow index approached zero. The low-fat dairy desserts incorporated with 0.2% Zedo gum or 0.3% almond gum did not significantly differ from full-fat control in terms of flow behavior characteristics. The low-fat dairy dessert containing 0.3% Zedo gum, despite showing stronger shear-thinning behavior, was less appreciated than full-fat control. It was shown that by using 0.2% Zedo or 0.3% almond gum, it is possible to develop a low-fat dairy dessert with desired rheological and organoleptical properties.

Sugar cane and the sugar produced from this plant contain various phenolic compounds with reasonable antioxidant potential. Therefore the aim of this study is to investigate the possibility of measuring phenolic compounds in brown sugar by DFT method. In this research work, sugar in second and third stages of cooking were sampled and by application of high performance liquid chromatography, the quality and the ratio of phenolic compounds were identified and determined. In the second stage, and for the first time, using the advanced computational method, the DFT density theory, based on Bond Desociation Energy (BDE) and Ionization Potential (IP), the antioxidant property of these types of compounds were obtained. For these calculations, particular attention has been paid to thermodynamic properties based on corrected enthalpy energy. The results indicated that by comparing BDE and IP, the identified compounds showed that chenifrol alcohol had the highest and benzoic acid had the least antioxidant activity in both sugar cooking batch(II) and sugar cooking batch(III). Based on the findings, it was concluded that phenolic compounds identified in sugar cooking batch(II) and sugar cooking batch(III), benzoic acid and chenifrol alcohol have the least and the highest antioxidant properties respectively.

  Roasting is a high temperature short time (HTST) heat treatment process and enhances the flavor of product and improves the textural and organoleptic properties of the nuts. In this study, a hot-air roasting process for the production of peanut snack was optimized by response surface methodology (RSM) over a range of air temperatures (140–180°C) for various times (10-30 min). The color parameters including lightness (L*), redness (a*), yellowness (b*) and total color differences (ΔE), textural characteristics (hardness and compressive energy), sensory properties, moisture content of the peanuts and energy consumption were used as response parameters to develop predictive models and optimize the roasting process. The results showed that by increasing the by temperature and time of roasting, the L*, b*, moisture content, hardness and compressive energy were decreased and ΔE* and energy consumption were increased. The result of RSM analysis showed that quality parameters could be used to control the roasting of peanut kernels in a hot-air roaster. In order to obtain the desired quality parameter, the optimum roasting for production of peanut snack was determined at 162°C for 29 min. This study revealed that RSM could be used to develop adequate prediction models for describing color and texture changes in peanut kernels during hot-air roasting. The changes in the quality parameters were adequately described by quadratic model. Successful optimization for the peanut kernels roasting process can also be made using desirability functions in RSM

Vegetables are known as a low-energy food source, rich in essentials and beneficial compounds for the body and might be regarded as an excellent nutritional supplement. The aim of this study is to evaluate some of the compounds present in some leafy vegetables under treatment with nano-chelates. This research was carried out in a completely randomized design with 7 treatments including two levels of iron, potassium and zinc nano-chelates (3 and 6 mg / l) in triplicate order. After about 4 weeks from sown of seeds, foliar application of iron, potassium and zinc nano-chelates was performed every two days for one week. A blank was carried out along with the experimental work. Characteristics such as total leaf chlorophyll, ascorbic acids, protein, superoxide dismutase and peroxidase activities, iron, potassium and zinc contents in leaves, were evaluated. The highest total chlorophyll and ascorbic acid contents were determined in the treatment concerned with iron nano-chelate (6 mg /l) in savory and parsley. The highest protein and superoxide dismutase and peroxidase activities and iron were obtained in treatment concerned with iron nano-chelate (6 mg /l) in fenugreek and the highest potassium content in treatment concerned with potassium nano-chelate (6 mg /l) was observed in fenugreek and the highest zinc in treatment concerned with zinc nano-chelate (6 mg /l) was determined in basil. There were not significant differences between the treatments at 1% level. All the treatments applied caused improved characteristics as compared to the blank. The best improved characteristics were obtained at the concentration of 6 mg / l of nano iron chelate, nano potassium chelate and zinc chelate.

  Color is one of the main parameters for food evaluation and marketing which can be improved by the application of natural colorants with known health effects. In this research, the addition of safflower aqueous extract as a natural colorant was studied to improve the qualitative parameters of potato chips. For this purpose, safflower aqueous extract was prepared at 0.5, 1 and 2% concentrations and were added to potato chips by immersion and spraying. Color, texture and sensory analysis were carried out at different time intervals of 0, 30 and 60 days of storage at ambient temperature. The results showed that a* and b* increased and L* decreased as the safflower extract concentration increased while all color indices decreased during storage, significantly (p<0.05). According to the results of texture analysis, there was no significant difference between the hardness (brittleness) of control and immersion type specimens (p>0.05) during storage, while spraying method caused higher hardness as well as less brittleness in all the samples. Totally, the potato chips prepared by immersion gained the highest sensory scores (color, odor, taste, texture and overall acceptance). Potato chips prepared by immersion containing 2% of safflower extract was chosen as the best sample due to the highest b* (45.22±0.77), least hardness (highest brittleness) (4.63±0.37 N) and the most overall acceptance score (4.50±0.51) after 60 days and immersion method was more effective than the spraying for improving the color of potato chips

  The recent literature search has introduced fennel and its extracts as potential products with excellent properties and characteristics. The aim of this investigation is to obtain fennel extracts and evaluate its antioxidant and antifungal activities. Water, acetone, methanol and ethanol were employed as solvents and extracts were obtained by soxhlet procedure. The amount of polyphenolic and flavonoid compounds of each extract was determined. In addition, the antioxidant activity of methanolic extract of fennel was evaluated based on DPPH radical scavenging activity. Afterwards, the effect of different concentrations of methanolic extract (0, 100, 250, 500 and 1000 ppm) and powder (500 and 1000 ppm) of fennel on the oxidantion activity of sunflower seed oil was investigated in terms of peroxide and thiobarbituric acid values during 15 days of incubation at 70 ⁰C. The antifungal activity of powder and extract of fennel against Aspergillus niger and Penicillium digitatum was also investigated by disc diffusion test. According to the obtained results methanol represented the highest efficiency in extraction of phenolic compounds. The results indicated that fennel extract, especially at high concentrations, showed high DPPH radical-scavenging activity, however its effect was lower than that of TBHQ. The results of oxidation activity showed that the extract and powder of fennel, decreased the oxidation rate of sunflower seed oil as compared to the control. The results of microbiology test indicated good antifungal activity of fennel extract against the two tested microorganisms. Considering the results, fennel extract can be applied as a healthy plant source with good antioxidant and antifungal activities.

  Antocyanins provide a pleasant and attractive appearance in fruits and vegetables particularly fruit juices. Therefore it is necessary to study the effect of hydrogen peroxide (H2O2) as a widespread material in packaging sterilant in aseptic processing systems on anthocyanins from various juices. In this study, the simultaneous effect of hydrogen peroxide in five different concentrations and three different temperatures (10, 15, 20, 25 and 30 mmol/L) and (10, 20 and 30 ̊C) on degradation of anthocyanins in Berberis vulgaris, Berberis cratagina and Beberis integerrima juices have been investigated. The degradation of anthocyanins in all treatments were fitted both zero and first order kinetics models. The results showed the degradation of anthocyanins in these three Berberis juices followed the first-order reaction kinetics. In most cases, the reaction rate constant (k) and half-life (t1/2) differed significantly among the three Berberis in various concentrations and temperatures (p<0.05). The difference between Berberis vulgaris juice and Berberis cratagina juice was lower. The reaction rate constant (k) increased and half-life (t1/2) decreased with increasing concentration of hydrogen peroxide in all juices. The temperature dependence of anthocyanins degradation was determined by calculating the activation energy (Ea) and temperature quotient (Q10). At the concentration of 10-20 mmol/L, Berberis vulgaris juice showed the lowest temperature dependence, whereas at higher concentrations (25 and 30 mmol/L) Beberis integerrima juice had the lowest temperature dependence. Anthocyanins from berberis species juices were found to be very susceptible to H2O2. Therefore, aseptic systems should be frequently controlled to ensure the effective removal of residual H2O2 from the food contact surfaces. Since the rate of anthocyanin degradation by H2O2 is highly dependent on temperature, cold storage of these juices is strongly recommended.

  Broiler chicken is one of the most popular products derived from poultry. Microbial growth and lipid oxidation are the primary factors of deterioration of this product in the fridge. Therefore this study is aimed to investigate the effect of Heracleum persicum essential oil (EO) on the extension of the shelf life and improvement of the sensory properties of broiler chicken under refrigerated storage condition. The samples of chicken breast were prepared in six groups including 2 control samples and 4 treated samples with H. persicum EO in four concentrations of 0.25, 0.5, 0.75, and 1% (v/w). All the samples were kept at 4 °C for 7 days. The samples were evaluated and compared regarding microbiological (total bacterial count, Escherichia coli and Staphylococcus aureus, and Salmonella), chemical (pH, TVN and TBA) and sensory (color, taste, odor, texture and overall acceptability) properties during this time at one day intervals. Statistical analysis was performed using two ways analysis of variance and mean values were compared with Duncan's multiple range test. The results showed that samples treated with different concentrations of H. persicum EO had lower bacterial counts and also lower amounts of TVN and TBA as compared to the controls during this study (p˂0.05). The samples treated with 0.75 and 1% of H. persicum EO as compared to other concentrations (0.25 and 0.5 percent EO) were more effective regarding the increase in shelf life (p˂0.05). Moreover, the samples that contained 0.5 and 0.75 H. persicum EO had desirable and acceptable sensory properties and general acceptance within 4 days. In general, the results indicated that H. persicum EO not only could delay microbial and chemical spoilage and extend the shelf-life of broiler chicken breast under refrigerated storage, but also could improve its sensory properties.

  In this research Spirulina platensis blue-green microalgae with unique nutrient content and numerous nutritional and therapeutic effects in various food products enrichment has been employed. Information concerned to fortify wheat flour with powdered Spirulina platensis microalgae to produce pasta is very limited. In this study, the effect of spirulina powder addition to pasta and evaluating the physico-chemical characteristics have been investigated. The effect of Spirulina platensis microalgae powder at 0.0, 0.25, 0.5, 0.75 and 1 (% W/W) concentrations on pasta have been studied and protein, fat, carbohydrate, total energy and iron were determined by standard procedures. physical examinations of the samples consisted of color and texture evaluations were Caused out by colorimetric and texture analyzer methods. The results showed that different levels of spirulina microalgae powder had significant effects on chemical parameters of pasta (P< 0.05). Also, interaction of different levels of microalgae powder on the pasta color index was significant(P< 0.05) while on texture index of pasta was not significant (P> 0.05). The addition of 0.25% of Spirulina platensis microalgae powder to pasta, has improved the nutritional value and physical characteristics of the product and a functional food has been formulated that will be available to the community