| Soft-shelled turtles have a high nutritional and medicinal value, which are the good raw materials to develop and make food. Owing to the rapid increase in the production of soft-shelled turtles these years, it gives us good opportunities on its deep processing. In this research, the two sizes of different growing periods of soft-shelled turtles were selected as raw material, their nutritive compositions of different months, different sizes and different parts were analyzed; additionally, the effect of storage conditions on the quality of slaughtered turtles, and the effect of the technic of stewing in soy sauce and storage condition were investigated to establish the evaluation criteria for product quality control system of pot-stewed soft-shelled turtles. The main findings are as follows:1. The analysis of the nutritive compositions of different growing periods and different size of soft-shelled turtles was done, which indicated that their nutrient content of different parts and same month has the significant difference (p<0.05), the highest value of water content, ash, crude fat, crude protein, collagen protein were respectively at different parts—limbs, back, internal organs, skirt hem, skirt hem; While, their nutrient content of the same parts of same size at different months has no significant difference (p<0.05). As a result, the 350g samples were selected to be materials of pot-stewed products considering the cost and convenience packaging.2. The effect of storage conditions on the quality of slaughtered soft-shelled turtles: The slaughtered samples were shored at 4℃and 20℃. The total bacteria count, TVB-N value, TB A value and histamine were all increased as the extension of time, while those of 20℃storage conditions is significantly higher than those of 4℃. Though there was little change of the quality stored in 8 hours of 4℃or in 2 hours of 20℃aftering killing, it should be made into finished products as soon as possible in the case of quality disgrade.3. The effect of the technic of stewing in soy sauce on the quality of soft-shelled turtles:The impact of salt concentration and time of pickling, and the amount of salt, rock sugar, MSG and soy sauce on the quality of product was investigated to determine the formulation and the best processing technical. As a result, the appropriate condition of pickling was with 2.5% salt in 60mins, and the optimal amount of stewing was 3% salt, 4% crystal sugar,0.4% MSG and 2% soy sauce. The selected stewing materials ratio of star anise, cinnamon, Fennel, Licorice, amomum, pepper, grass fruit, clove, pepper was 13:8:6:6:4:5:3:3:4. 4. Effects of different storage temperature on the quality of the pot-stewed soft-shelled turtles:The pot-stewed products were stored respectively at the temperature of -0.5℃,4℃and 20℃, the total bacteria count, TVB-N value, TBA values and histamine were all gradually increased as the extension of time. While the quality change at 20℃is obviously higher than that at -0.5℃and 4℃, the indexofquality of the products has not surpassed the national security standards after 30 days storage of -0.5℃,4℃and 20℃.5. The establishment of quality control system of the pot-stewed product:Through the analysis of microbiological and chemical factors in storage condition of pot-stewed soft-shelled turtles, it is confirmed that raw material, slaughter and sterilization are the critical control points to establish the HACCP control system of pot-stewed soft-shelled turtles.
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