نشریه فرآوری و نگهداری مواد غذایی
سال سوم شماره 2 (پیاپی 10، پاییز و زمستان 1390)

At present study, response surface methodology was used to determine the optimum processing conditions to acheive maximum of extraction yield, phenolic compounds and antioxidant activity during Ultrasound-assisted extraction of licorice root. Temperature (20-50 ºC), processing time (30-90 min) and ultrasound frequency (35 and 130 KHz) were the factors investigated with respect to phenolic compound, extraction yield and antioxidant activity. Experiments were designed according to Central Composite Rotatable Design with these three factors each at three different levels, including central and axial points. With respect to the dependent variables linear effects of all of the three independent variables on phenolic compound, extraction yield and antioxidant activity were found to be significant. The optimal condition in ultrasonic assisted extraction method was the extraction temperature of 50 oC, extraction time of 68 min and frequency of 113Hz. Under these conditions, the extraction yield of licorice root and total phenolic compounds were 40.0719 mg/g and 14.265%, respectively. Also, in this study results were compared with those obtained by soxhlet extraction.

Basil seed gum (BSG) was used as a fat replacer in formulation of low-fat set yogurt and its characteristics were studied. Basil seed gum was added to reconstituted skim milk at five levels (0.01, 0.04, 0.07, 0.1 and 0.2%). Considering a blank sample, the mixtures were inoculated using a DVS yogurt starter culture and the obtained yogurt stored at 5°C. Physico-chemical properties of the yogurt samples such as pH, acidity, syneresis, apparent viscosity, hysteresis area, and microstructure, textural and sensory properties were studied after one and seven days storage. During one week storage, the pHs of samples did not show any significant differences. However, acidity of yogurt significantly changed (P<0.05). The textural evaluation of the samples contains 0.1 and 0.2% BSG were significantly different from the others and showed the lowest modulus of elasticity. Apparent viscosity, modulus of elasticity, values of syneresis and hysteresis of yogurt decreased as BSG concentration changed from 0.01 to 0.2%. Scanning electron microscopy (SEM) of yogurt samples contains 0.1 and 0.2% BSG were significantly different from the blank sample and showed smoother microstructure. The analysis of sensory properties indicated that the color, odor and flavor of samples did not show any significant differences. Although, the differences between the samples and the blank in terms of sourness, hardness, consistency in mouth, creaminess, syneresis and total acceptance were highly significant (P<0.01). The results indicated that Basil seed gum at level of 0.2% which has high water holding capacity, good sensory properties and strong interactions with milk proteins is a suitable fat replacer to develop a formulation of low-fat set yogurt.

Stress relaxation is one of the defined tests to characterize the viscoelasticproperties of agricultural materials. Stress relaxation data are very importantbecause they provide useful and valuable information such as fruit firmness andripening, food processing and predicting changes in the material during mechanicalloading. Viscoelastic behavior of pomegranate that is cultivated in Iran has beenstudied in current research. For this purpose, stress relaxation test was conductedwith Ardestani cultivar of pomegranate for three sizes (small, medium and large)and three different harvesting times. Two common models (the GeneralizedMaxwell model and the Peleg model) were fitted to the experimental data. ForMaxwell model coefficients, values for RMSE, R2 and MAPE less than 0.003,greater than 0.98 and less than 0.385 were obtained respectively. The value ofMAPE has been acquired for all harvesting times and pomegranate sizes except forpomegranate with medium size in first harvesting time. Results showed thatMaxwell model describes the tension relaxation behavior of pomegranate withlower error than Peleg model in a suitable way. The ability of artificial neuralnetworks technique as an alternative to predict the viscoelastic behavior ofpomegranate was assessed. This assessment showed that artificial neural networksand Maxwell model can predict the tension more reliably and more precisely thanPeleg model. According to analysis of tension data using models coefficients,pomegranate behaves like solid viscoelastic in every harvesting stage. It also showsthat elastic behavior of pomegranate is more in the third stage of harvesting thanfirst and second stages.

Rice bran is a by-product of rice milling industry, which contains considerable amount of protein, fat, carbohydrate and minerals. According to this chemical composition, it seems that rice bran might show suitable functional proprties. In this study chemical composition and functional properties (including water and oil adsorption, emulsion capacity and foam stability) of rice bran obtained from four Iranian rice varieties, namely Neda, Tarom, Fajr and Shirodi were investigated. Results showed that the lowest content of moisture, fat and ash and the highest of fibre and carbohydrate belonged to the Fajr variety. Bran of Neda variety had the lowest amount of protein and the highest content of fat and ash. Brans from Tarom and Shirodi varieties showed the highest amount of moisture and protein. Results of functional properties showed that Shirodi and Tarom varieties had the highest (2.63 g/g sample) and the lowest (2.04 g/g sample) water adsorption capacity, respectively. Oil adsorption capacity significantly diffrent among the four varieties, so that it ranged from 2.68 (g/g) to 3.52 (g/g) for Shirodi and Neda, respectively. Bran of the all four vareities showed significantly different foam capacity and foam staibility (P<0.05). It was concluded that rice bran has the potential to the used as an ingredient in functional food formulations to engance nutritional values and functional properties of the product.

Newadays, additives are extensively used in the baking industry for several desirable properties, such as improving bread quality, enhancing nutritional value, retarding staling and preventing it from spoiling.This research was carriedout to evaluate the effects of Pectin gel on rheological properties of wheat flour dough and physicochemical (volume, specific volume, hardness, cooking loss and water activity) and sensory properties of Gholach bread. Hydrocolloid of Pectin was added at 0.5%, 1%, 1.5% w/w (flour basis) to wheat flour. The rheological measurement of the dough was investigated using farinograph instrument. Results of rheological evaluation of dough showed that addition of pectin gel and its increasing levels resulted in increase in the water absorption capacity, Arrival Time, dough Development Time, dough stability, Departure Time and Time to breakdown, while the dough degree of softening after 10 and 20 minutes and mixing Tolerance Index were decreased in comparison with the control sample. Results of evaluating of water activity showed that addition of Pectin gel decreased water activity. In relation to technological properties of bread, it was assayed that addition of Pectin gel in level 1.5 percent increased volume and specific volume. As results of sensory evaluation of bread samples, showed that addition of Pectin gel in level 1.5 percent had the best quality results.

In this study Quail meat was irradiated at doses of 0, 1.5, 3 and 5 kGy of electron beam irradiation and kept in a refrigerator (4±1°C). Then the effects of irradiation and maintenance of refrigeration temperature on microbial quality, chemical and cooking loss were evaluated. The results of microbial analysis indicate that all radiation doses of 1.5, 3 and 5 kGy caused a significant decrease (P<0.05) in the number of aerobic mesophilic bacteria, lactic acid bacteria, fungi and yeasts. Radiation doses of 1.5 and 3 kGy caused a significant decrease (P<0.05) in the number of coliforms. Irradiation significantly (P<0.05) increased the initial TBA of samples and refrigerated temperature increased the TBA value significantly (P<0.05) in all samples, so that the level of TBA increased from 0.3 to 3.58. In this study the cooking loss of control and irradiated quail meat was evaluated. About this value the results showed the irradiated quail meat was increased in comparison to nonirradiated samples significantly (P<0.05), so that the level of cooking loss increased from 31.56 to 41.65. Thus, this study clearly indicated that the electron beam irradiation of quail meat has positive effects on overall characteristics of quail meat and extend the shelf life during refrigerated storage.

The objective of the present study was to determine the fatty acids composition in raw muscle and also cooked by shallow fat frying of Cyprinus carpio, 2011. Ten samples of farmed carp were collected of Azadegan culture collection in Ahwaz. In this study according to data were analyzed with SPSS17 software and ANOVA ω3, ω6, EPA, DHA, PUFA, Arashidonic and Palmitic acid were6.03±0.09, 12.20±0.18, 1.02±0.01, 1.87±0.02, 18.23±0.27, 0.34±0 and 0.17±0 g/100g in raw muscle higher than cooked by shallow fat frying, but MUFA, SFA and EPA/DHA were 53.14±0.02, 34.88±1.11 and 0.66±0.06 g/100g in cooked by shallow fat frying higher than raw muscle. In this study SFA, PUFA, EPA, DHA, MUFA, ω3, ω6, Palmitic acid and EPA/DHA significance different between them(P<0.05), but Arashidonic no significance different between them (P≥0.05).