| Summary: | 碩士 === 國立中興大學 === 動物科學系所 === 102 === In Taiwan, the consumption of duck meat has been changed and trended to be part of meat such as breast and thigh as well as also resulted in a large production in duck by-products such as head and neck, wing, feet, gizzard, and frame etc. These duck by-products usually are processed as marinated products which are very popular by local peoples. Generally, the food can be kept long shelf life and prevented bacteria from growing by low temperature preservation. Low temperature preservation is need more energy to keep and this technique is unsuitable for save energy and decrease carbon policy in many countries. Therefore how to keep the quality of food during room temperature storage are hot research topics for food scientists in the present. Food additive, package and sterilization usually are used to treated food and the best model to reach the target. Thus, the objective of this study was to evaluate the effect of sodium lactate level and commercial sterilization on the quality of marinated duck by-products with vacuum package during storage at room temperature (28 ±2℃). The optimum condition of sodium lactate level and commercial sterilization will be set in the first experiment and the quality of marinated duck by-products treated by the optimum model will be evaluated during storage at room temperature (28 ±2℃) for 8 weeks in the secondary experiment.
The results of the first experiment showed that the count of C. perfringens was non-detection in all of treatments when marinades treated with different levels of sodium lactate (0, 1.5, 2and2.5%) and different sterilization condition(121℃ for 15, 30, 45 and 60min) then incubated at 37℃ for 7 days. In the sensory evaluation of marinated duck by-products which sterilized at 121℃ for 15, 20, 25 and 30min, the flavor, texture, color and overall acceptance of marinated duck by-products (gizzard, wing and feet) sterilized at 121℃ for 15 min the best results compared to the other treatments.
The results of the microbial quality of marinated all duck by-products treated with 2% sodium lactate and 121℃ for 15 min during storage at room temperature showed that the total plate count and anaerobic plate count of marinade of duck by-products were non-detection during whole storage at room temperature (28 ±2℃). The pH value of marinade if all duck by-products was no significantly different during storage at room temperature. In the analysis of peak force, shearing energy of duck gizzard was no significantly different during storage at room temperature. The gelatin concentration of marinade of duck feet was significant higher than wing and gizzard, and was (2095.22, 1423.4 and1318.14mg/ml) in order. The gel strength, hardness and elasticity of marinade from marinated duck by-products were no significantly different during storage at room temperature. The VBN value of duck gizzard was no significant changes during storage at room temperature. In the sensory evaluation of marinated duck by-products, the flavor, texture, color and overall acceptance were no significant changes during storage at room temperature. In the gel sensory evaluation of marinade from marinated duck by-products the flavor, texture color and overall acceptance were no significant changes during storage at room temperature.
In conclusion, marinated duck by-products with 2% sodium lactate and vacuum-packaging through sterilized at 121℃ for 15 min can completely inhibit the growth of Clostrdium perfringens and also can keep the quality of marinated duck by-product at room temperature (28 ±2℃) for 8 weeks.
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