فصلنامه پژوهش و نوآوری در علوم و صنایع غذایی
سال پنجم شماره 2 (تابستان 1395)

Due to the disadvantages of synthetic packaging materials such as migration into food, polluting the environment, difficult recovery, high costs of raw materials and production, natural biopolymers have recently been paid more attention as alternatives to the petroleum-derived plastics for packaging. The aim of this study was producing biodegradable edible films based on native tragacanth from Iran and determining their physical and mechanical properties. Also, the effects of different percentages of glycerol as a plasticizer (30%, 40% and 50%) on the films properties were investigated. According to the results, tragacanth based films showed appropriate mechanical properties and high transparency. Different percentage of glycerol did not affect the physical properties of the samples, but made some changes in mechanical properties. Among all treatments, films with 30% glycerol showed higher tensile strength in comparison to the other samples. Also, films with 50% glycerol showed more %E and lower stiffness. Because of high solubility of tragacanth films, they cannot be used in film production alone, but it is an appropriate candidate for composite films.

In situ solvent formation microextraction (ISFME) as a green¡ simple and sensitive method has been proposed for preconcentration of trace quantities of hazardous brilliant green in aqueous samples containing very high salt concentrations by UV-Vis spectrophotometry. In this technique¡ the extraction phase is simultaneously formed in situ. A water-miscible ionic liquid (IL) ([Hmim][BF4])¡ is first added to the sample¡ followed by addition of sodium hexafluorophosphate (NaPF6¡ as an ion-pairing agent) to obtain the hydrophobic IL ([Hmim][PF6]). As a result¡ a cloudy solution is formed due to the formation of hydrophobic IL ([Hmim][PF6]). All the critical parameters affecting the analytical performance of the method were investigated. Under the optimized conditions¡ the enhancement factor was 70. The detection limit and precision (RSD) were 0.1 µg L−1 and 3.3% (n=6) respectively. The applicability of the proposed method was evaluated by determination of trace amounts of brilliant green in various water samples for fish farming.

In this research¡ application of prebiotic inulin compound in edible coating of fish fillet and its impact on the functional properties of the product was studied. Rainbow fillet was coated by 5% alginate and inulin in concentrations of 0¡ 10¡ 20¡ 30 and 40% (w/w). After deep frying¡ sensory properties were investigated by quantitative descriptive analysis and textural properties were tested by texture analyzer instrument via compression test. Based on sensory assessment more alteration was shown in flavor group attributes including flavor of frying¡ fish flavor and sweetness and also internal product color. Results of texture analyzing showed that maximum amounts of hardness¡ chewiness and gumminess was related to fillets with no coating. Cohesiveness and springiness changes of fried fillet in various treatments were not significant (P≥0.05) while changes observed in the trend of hardness and gumminess were similar and contrary to springiness. In conclusion adding functional ingredient of inulin to edible coating of fish fillet in 30 and 40% concentrations could be used without creating significant effects of sensory¡ taste and textural properties of the final fried product.

This study was carried out to compare the influence of sugar contents (0.5¡ 1¡ 1.5%) and fermentation times (8¡ 16¡ 24 h) of Lactobacillus plantarum as sourdough specific starter culture on properties and staling of Barbari breads produced with two different extraction rate flours (69 and 76%). The effect of the above mentioned parameters on properties of sourdoughs prepared from these two types of wheat flour was evaluated in a split plot design. The results showed that¡ different fermentation times and sugar contents had significant effect (P≤0.05) on sourdoughs total titerable acidity. After processing of Barbari breads with sourdough treatments¡ the specific volume¡ crumb firmness (texture analysis) and porosity (Image j method) were examined during 4 days of storage. Based on the results¡ 96 h after baking the lowest and highest amounts of crumb firmness were observed in Barbari bread prepared from 76% extraction rate flour and 24 h sourdough fermentation and 1% sugar content and also Barbari bread prepared from 69% extraction rate flour and 24 h sourdough fermentation and 1.5% sugar content¡ respectively. Furthermore¡ most of Barbari breads prepared from 76% extraction rate flour had higher specific volume and porosity and also less total acceptance than the Barbari breads prepared from 69% extraction rate flour.

The industrial and domestic use of microwaves has increased noticeably owing to the advantage of saving energy and time¡ as well as improving nutritional quality of foods over the past few decades. However¡ rapid staling rate is one of the drawbacks of microwave baked products. Formulation improvement by adding dietary fibers is one of the ways to solve this problem. Therefore¡ the aim of this work was to investigate the effect of adding Persian gum (1.20%) and carrot pomace powder (6.45%) as sources of dietary fiber on staling rate of microwave pretreated (400 W for 60s) donut using a completely randomized design (statistical significance was determined at P

Juice cloud and turbidity are considered as desirable properties in lime and other citrus juices. The turbidity is influenced by the presence of pectin in citrus juice. Pectin methylesterase (PME) causes cloud loss due to its function in desterification of the pectin. Thermal processing is commonly used to inactivate this enzyme. As the first stage of the heating process¡ the come up time (CUT) plays a considerable role in PME inactivation. The aim of this study was to investigate the PME inactivation¡ turbidity and fractal dimension (FD) changes during lime juice thermal processing using conventional (water bath) and infrared (IR) heating at 60¡ 70¡ 80 and 90 oC. The results showed that by rising juice temperature¡ the PME inactivation and the turbidity increased during both thermal treatment methods. Therefore¡ the cloud particles remained suspended and less particles aggregation took place to form fractal structures¡ resulting in a homogeneous distribution of cloud particles and FD reduction. Due to shorter CUT¡ the samples heated by IR showed higher PME retention and FD in comparison with conventional processing.

To stimulate the production of Cumin aldehyde as an odorant with application in food sciences via co-cultures of cells¡ two medicinal plants¡ Bunium persicum and Carum carvi¡ were chosen. The cell cultures of both plants were established separately. In this study some basic experiments were also done due to the fact that no research reports were found on C. carvi in case of seed germination¡ callus induction and establishment of cell suspension cultures. The cells of B. persicum and C. carvi were combined together in different ratios (100:0¡ 25:75¡ 50:50 and 75:25) to study their interaction on cumin aldehyde production in a co-culture system. For Gas chromatography (GC) analysis of cumin aldehyde¡ the cells and medium were homogenized and then extracted with ethyle acetate at room temperature and then analyzed by GC. The results revealed that in contrast to black zira for seed germination process¡ Caravie seeds do not need chilling. It has also been found that sucrose at the level of 3% is suitable for increasing the biomass of Caravie cells in MS medium. The results of co-culture of B. persicum and C. carvi cells demonstrated that at the combination of B. persicum (25%) and C. carvi (75%) the production of cumin aldehyde could be increased to the level of 23.1 mg/100 g extract after five weeks which is higher than B. persicum (100%) at similar period with 17.5 mg/100 g extract. It is also found that the production of cumin aldehyde has an increasing trend till 5th week and then decreased to the minimum level in the 7th week.

This study evaluated the effects of ozonated water (0.2, 0.5, and 1 ppm) alone with different exposure times (5, 10, and 15 min) and combinations of ozonated water (0.2, 0.5, and 1 ppm) with 1% Lactic acid during 10 min exposure for control of Escherichia coli (As a Gram-Negative food infection bacteria), Staphylococcus aureus (As a Gram-Positive food infection and toxigenic bacteria) and total count of poultry carcass, at the same temperature condition of chiller water (0-4 C) and samples immediately were analyzed for microbiological tests. The results showed that there were significant differences (P