Journal of food science and technology
Year:2013 | Volume:10 | Issue:38|Papers Count:16

Effect of green tea extract and its natural antibacterial on microbial spoilage rainbow trout during ice storage was investigated. In this research fishes in whole fish form and dipped in antibacterial solutions (200, 400, 600 ppm) for 90 minutes and then were icing. During storage period (16 days), spoilage microbial indices (TVB-N, TVC, PVC) and pH with interval of 4 days were measured and compared with control treatment. Based on obtained results in all of treatments by passing time the value of total volatile nitrogen increased significantly (P<0.05). But this increase in treatment of 600 ppm performance slowly. In control treatment by passing time Total viable count increased significantly (P<0.05). Except in level of 600 ppm, other levels did not significantly different until sixteenth day in comparison with control treatment. In passage of time, Psychotroph viable count (PVC) in all of treatments was increased while control treatment in twelfth day and levels of 200 and 400 ppm in final period storage time were aggressive allowable content but 600 ppm level in final period was lower than allowable content (6.89±0.15 log cfu/gr). The value of pH was increased in all of treatments. Obtained results showed that green tea extract with dipping whole fish in consternation of 600 ppm was suggested for retardation of microbial spoilage in rainbow trout during storage in ice.

Chickpea proteins have received attention during recent years owing to their higher biological values and better functional properties than oilseed proteins. In present study, the effect of protein extraction method from kabuli chick pea seeds on functional properties obtained by tow extraction method includes alkaline extraction and acidic extraction was investigated. In research protein extraction had to pH=2.5 and pH=9.5 and followed by Isoelectric precipitation (pH=4.5). Functional properties of Kabuli chickpea protein isolates such as oil absorption capacities, water absorption capacities, foaming capacity and stability, emulsion capacity and stability were evaluated. All experiments were performed in triplicate and Duncan multiple range tests with a confidence interval of 95% was used to compare the means. Results showed that; Isolates obtained by acid method had higher emulsification (capacity emulsion 87.77% and stability emulsion 87.92%), and foam properties (capacity foam41.42% and stability 57.16%) than alkalin method. While alkalin method enhanced water absorption capacities (1.52 g/g) and fat binding capacities (1.68 g/g). Whereas suitable functional properties of chick pea protein isolate could be used for substituting other proteins in food systems.

Walnut is considered a valuable nut crop because of high valued nutritional compounds like unsaturated fatty acids. The aim of this study was to determine protein, oil and fatty acid compounds of some walnut cultivars and genotypes. The investigated cultivars were ‘Chandler’, ‘Hartley’, ‘Pedro’, ‘Serr’, ‘Z60’, ‘Z63’ and ’Z30‘. The oil content was measured using the soxhlet extraction method based on dry weight, and the percentage varied from 60 to 75 percent. Fatty acids compositions were measured using gas chromatography (GC). The results in mentioned cultivars showed that the unsaturated fatty acid compounds were dominant in walnut oil. The main fatty acids were linoleic acid (44.84-68.44%), linolenic acid (15.31-23.92%), oleic acid (8.02-31.62%), palmitic acid (2.42-6.44%) and stearic acid (1.65-2.48%), respectively. Protein content varied from 14.67 to 20.38%. In conclusion, ‘Hartley’, had the highest and ‘Z63’ had the lowest unsaturated fatty acids among the studied cultivars. ‘Z63’ had the lowest and ‘Z60’ had the highest saturated fatty acids among all of the cultivars.

The purpose of this research was to study and analyze the component of adoption of agricultural organic products from the viewpoints of consumers. A descriptive and correlation design was used for the research with data collected using questionnaire. The statistical population of this study consisted of Karaj urban residents that a sample of 306 people was selected using proportionate stratified sampling technique. A questionnaire was the main tool of study. The validity of the questionnaire was approved by the judgment of a panel of faculty members of the Department of Agricultural Extension Education, University of Tehran. In order to measure the reliability of the questionnaire, Cronbach Alpha coefficients were calculated for the main scales of the questionnaire, which was more than 0.70, indicating that the tool of study was reliable. SPSS (Statistical Package for Social Science) was used to analyze the data. The findings showed that the consumers’ knowledge of organic products was at medium level. Also, consumers’ attitude toward using organic products was at neutral and favorable levels. Finally, factor analysis showed that four most highly ranked factors influencing the adoption of organic products were educational, access, improving product characteristics and supportive services which explained 26.60, 23.61, 9.41 and 8.81 percent of total variance (68.42%).

Introduction: Pure water freezes at zero degrees of Celsius. By dissolving any material in the water its freezing point will be decreased, similar to water, some ingredients of milk such as lactose, ion Chlorides decreases the freezing point. The main factors affecting the freezing point of milk are: added water during milking and gathering, high microbial load, mastitis, adulteration including the addition of Ionizable materials for example salt and etc.Objectives: To determine the average bovine milk freezing point, the percentage of none-fat-solid (SNF) and elemental mineral content(EMC) at the same time.Materials and methods: This is a descriptive analytical study which was done in Kermanshah province by using 100 milk samples from complete milk of healthy cow in definite time point by simple random sampling. The samples transported to laboratory in less than 3 hours, freezing point of each sample has determinated by calibrated cryoscope, the percentage of SNF and EMC has determinate by calibrated Milk analyzer.Results: beyond standard conditions of milking, collection and immediate testing, results showed that mean freezing point of milk was -0.519, mean SNF was 8.23 and mean mineral percentage was 0.74.Conclusion: Since the Institute of Standards and Industrial Research of Iran in the 4th revision of the pasteurized milk standard (Standard 93) has limited the percentage of SNF of milk to 8 and freezing point to -0.507 to -0.545, which are not at the same line. Moreover, other factors such as EMC have underestimated, we suggest that the freezing point of milk without measuring EMC is invalid, and maybe increases of milk adulteration by adding inonizable materials such as salts.

Active packaging is one of the innovative food packaging concepts which has been introduced to market as a reply to continuous changes in consumers demands. Active packaging modifies the packaging atmosphere condition in such a desirable way that results in shelf-life increase.In contrast to the traditional concept that packaging should preserve the quality of the product with minimal product/packaging interaction, new developments achieved in the last decades considers the benefits of interactions between package and product. Active modified packaging has been used for food preservation over the last twenty five years specially in Japan and USA. The application of different kinds of this package is developing continuously.Active packaging includes additives that can maintain the freshness of the product and have different potentialities. Active agents are in contact with food stuffs directly or indirectly and can be in the forms of oxygen and carbon dioxide scavengers, moisture and ethylene removers or emit ethanol and flavors.Those with the ability to change physical properties like self-heating or cooling are also considered an active package.Active packages have been used for a variety of food stuffs such as cakes, pizzas, fresh dough, cheese, meats and its products, fruits, breads etc.

Citrus disinfection has the major effect to prevent fungal attacks during storage. In this research, Thompson orange fruit was disinfected with ortho phenyl phenol solution by thermal fogging machine and then some of the samples coated by Carnuba wax. Physicochemical properties of orange samples (disinfected; disinfected-wax and control samples) were evaluated during three months storage. Factorial experiment design was selected to find the effect of coating and storage time on orange quality properties. The results showed that the effect of coating on all measured quality properties, and the effect of coating and storage time on pH values were significant (p<0.01). The amount of pH value of disinfected sample was significant (p<0.05) and was higher than the rest of the samples. So disinfection treatment enhanced fruit resistance against fungal attacks. Amount of total soluble solid and acid total of fruit juice for disinfected-wax samples decreased and increased during storage, respectively, which this trend could indicatefermentation phenomenon in the fruit. Therefore, disinfection with ortho phenyl phenol solution by thermal fogging machine was effective and preserved the fruit quality against fungal diseases during storage period.

High intakes of trans fatty acids (TFAs) is an important risk factor of several disease's specially cardiovascular diseases. Common sources of TFAs are margarines and foods containing partly hydrogenated vegetable oils. Some of the confectionary products like Danish pastries are produced using a kind of partially hydrogenated vegetable oil. Our study was developed to determine the fat content and fatty acid profile of Danish pastries produces in Tehran. 30 of Tehran confectionary producers were randomly chosen using the data from Iran’s national center of statistics, and samples were collected from them. The fat content of samples was extracted using rotary and fatty acid composition of them was determined using GC-FID. Estimation of fatty acid contents of samples performed using SPSS ver 15. Our study showed that an average of 29.5%±0.5 of weight of Danish pastries produced in Tehran is fat. Trans fatty acids consist of an average of 22.3%±0.75 of extracted fat. The mean value of saturated fatty acids in samples was 34.2%±0.78. According to the results of this study, each one average Danish pastry that weighs 60 gr, includes approximately 18 gr of fat. About 4 grams of this fat consists of trans fatty acids that are two timed more than the upper limit for taking trans fatty acids in a day.

Protein rich legumes are suitable for the production of edible films and coatings. In this research, pea protein isolate was obtained from defatted pea flour by alkaline extraction and acid precipitation. Then edible films were prepared from pea protein isolate. The effects of protein and glycerol concentrations on water vapor transmission rate (WVTR), mechanical properties, thickness, opacity and total color difference (DE) of the films were evaluated, using response surface methodology (RSM). The results showed that WVTR, elongation, DE, thickness and opacity were increased, while tensile strength decreased by glycerol concentration. Increasing the concentration of protein increased tensile strength, opacity and DE, while decreased WVTR and elongation of the films. The model developed by RSM for the physical and mechanical properties of the films had high coefficient of multiple determination (R2>0.87) and significant F values.

In this research, different amounts of gum tragacanth (0.5%, 1%, 1.5% and 2% w/w) was added to wheat flour and its effects on bread quality parameters including moisture, specific volume, crumb firmness, color, water activity and bread staling during storage was evaluated. The results suggested that addition of gum tragacanth increased moisture but decreased crumb firmness, loaf volume and specific volume in all samples with reference to the control sample. Measurement of crust and crumb color showed that addition of gum tragacanth at all concentrations significantly decreased lightness of crust and crumb but increased red- and yellowness of both crust and crumb (p<0.05). Results of evaluation of water activity showed that this factor decreased during storage of breads in all samples. In relation to staling of bread samples, it was experienced that addition of gum tragacanth and increase in its levels, significantly reduced staling in comparison with control sample, as bread sample containing 2% gum tragacanth showed the least staling whereas control sample showed the highest staling rate. In addition, during storing period staling of all samples increased significantly.

Ten semi-theoretical and empirical models were fitted to the experimental data to evaluate and select the best model for thin-layer drying of pomegranate arils. Experiments were conducted at six temperature levels of 45, 50, 55, 60, 65 and 70oC and three levels of air velocity (0.5, 1 and 1.5 m/s). Microwave pretreatments were used for samples and the results were compared to those of control (no pretreatments). Regression analysis of mathematical models showed that the Midilli et al. model fitted best to the measured data. Midilli et al. model coefficients increased with increasing temperature and air velocity. Also, the results of statistical analyses showed that pretreatment of pomegranate arils significantly reduces drying time.

The drying method, drying temperature and grain moisture content are parameters that affect on the milling waste (broken grains). At this study, effects of drying temperature with two levels (40 and 60oC), grain moisture content with four levels (8, 10, 12, 14% w.b.) and Guilan common paddy rice varieties with three levels (Hasani, Hashemi and Alikazemi) were investigated on the milling waste. Samples were milled by a laboratory rubber roll huller and laboratory abrasive whitener. The obtained results of data analyze showed that Hasani variety have minimum of waste mean (12.27%) with significant difference respect to Hashemi (15.32%) and Alikazemi (15.86%) varieties. With increasing drying temperature from 40 to 60oC, hulling waste mean was increased significantly from 11.62% to 17.64%. With increasing of paddy grain moisture content from 8 to 14%w.b., hulling waste mean was decreased significantly from 20.83% to 8.64%. At among of tested varieties, the minimum (21.05%) and maximum (30.21%) means of husking waste obtained for Hashemi and Hasani varieties, respectively. Significant decreasing of whitening waste mean from 31.33% to 19.69%, obtained due to reduction of drying temperature from 60oC to 40oC. With increasing of paddy final moisture content from 8 to 14% w.b., whitening waste mean was decreased from 30.84% to 19.59%.