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In this study, effects of coating materials: methylcellulose-wax; and wax on physic-chemical and sensorial characteristics of Thomson navel orange at 8 °C were evaluated. Weight loss, vitamin C, total soluble solid (TSS), acidity (TA), and sensory evaluation every two weeks for 16 weeks of storage were analyzed. Fruits were coated with commercial wax or composite methylcellulose-wax (MC, 9: 10, w/w) using immersion treatment. Uncoated fruits were used as control ones. This research was performed using a factorial experimental model in a completely randomized design with 5 replications at an accuracy rate of 95%. Coatings by wax were the most effective in reducing weight loss. Fruits coated with composite coating materials, had the highest level of vitamin C in comparison with other samples. TSS and TA of all samples decreased during storage, while the TSS / TA ratio increased in all treatments. Fruits treated with methylcellulose-wax within 10 and 16 weeks of storage preserved TA values more than other treatments. The results of sensory evaluation showed that the least desirable flavor was related to 8 weeks after storage. Within 10 and 16 weeks, the highest off-flavor was related to the fruits coated by wax Freshness of fruits decreased during storage. No significant difference was observed between the fruits coated by MC-Wax and wax.  

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In this research stirred yoghurt prepared by addition of three sources of omega-3s; encapsulated fish oil, flaxseed oil and mixtures of the two oils at four levels (0, 650, 1625 & 3250 mg/1000 ml) and two addition step (after heating and after incubation step). Experiments were carried out in three replicates and a completely randomized factorial design was used for statistical analysis. Oxidative stability and fatty acid profiles were determined during the first, tenth and twentieth of storage time. The peroxide values and thiobarbituric acid values of enriched yoghurt with fish oil and enriched yoghurts after heat treatment are significantly highest. Polyunsaturated fatty acids and omega3 of enriched yoghurt with flaxseed oil is significantly higher than other samples. Therefore, it could be achieve the stirred yoghurt with higher oxidative stability by enrichment with flaxseed oil after heat treatment.

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In order to improve the quality of shrimp (Litopenaeus vannamei) at refrigerated temperature (4±1°C), the shrimp samples were coated with solutions of chitosan (0, 0.5, 1, 1.5 and 2%), gelatin (0, 2 and 3%) and combination of them in 15 treatment group.Preservative effect of the coatings was evaluated by biochemical analyses, microbiological assays and physical measurements over 8th day of storage time. The findings indicated that 1%chitosan and 3%gelatin based coating was superior to others in preservation spoilage, inhibiting oxidation, improvement physical properties. The coating significantly (p≤0.05) reduced chemical spoilage as reflected in pH and total volatile basic nitrogen, microbial growth as reflected in total and psychrotrophic bacterial count and lipid oxidation as displayed in peroxide value and thiobarbituric acid compared to other treatment. Also, coated shrimps with the optimized coating were significantly (p≤0.05) indicated improvement in weight loss, color as reflected in a*, b* and L* values and texture as reflected in hardness compared to others. The optimized coating could enhance the shelf life of shrimp under refrigerated storage.  

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The aims of this study was improve the rheological charactristics of gelatin obtained from the skin of the Big head by rheological test. In this study gelatin  was extracted from big head (Hypophtalmichthys nobilis) fish skin and the effect of microbial transglutaminase (MTGase) on gelatin in different concentrations (1, 3 and 6 u/g gelatin) and reaction times (15, 30 and 60 minutes) was examined. The result showed that addition of MTGase in minimum concentration and reaction time ( 1u/g gelatin in 15 minute reaction time) increase the gel strength from 228±1g to 250g significantly  (p≤0.01) whitout the changing the color of result gelatin. Furthermore, increasing concentrations of MTGase redused the gel strength of gelatin. Also the addition  of MTGase increased the viscosity in all shear rates and improved melting and gelling point. The increase in storage modulus (G') values with the addition of MTGase indicated the formation of firmer gels and also changes in G' and G" values during the heating and cooling sweep test showed increase in melting point and gelling point. It is conclude that the application of 1-6 U/g of MTase can improve the quality of driven gelatin from big head fish.

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