Sterilization process of inoculated rice mash fish

Rice mash fish is one of the traditional fermented fish products in China, with unique flavor, taste and bright color. However, shortcomings such as long fermentation time, low safety, short storage period and inconvenient consumption, limit its commercial development. Modern biological fermentation technology (inoculated fermentation) can effectively shorten the fermentation time and improve the safety, while thermal sterilization technology provides a way for prolonging the storage life and for being convenient ready-to-eat. In order to explore the sterilization process of inoculated rice mash grass carp, the influence of key technological parameters such as drying degree and sterilization condition on physicochemical property, sensory property and preservation quality was analyzed in this study. The results showed that the water activity (Aw) of the final product was 0.86, 0.82 and 0.78, under the drying degree of 63.48%, 55.37% and 47.76%, respectively. At the F-value of 5 min, the bulgy product was observed after sterilization treatment at 90 ℃ and 95 ℃. When F-value was more than 6.5 min, the product was commercially sterile. At the same time, a* value significantly increased (P < 0.05) with the increase of sterilization temperature, while no obvious changes were observed in L* value, b* value and shear force (P > 0.05). The highest sensory score was 84.9 at the sterilization temperature of 95 ℃ with 17.4 min. During the 120 d storage period, Enterobacteria was not detected in the products both stored at 4 ℃ and 25 ℃, and the product stored at 4 ℃ had a better sensory quality. Therefore, the optimal sterilization conditions for inoculated rice mash grass carp are as follows: F=6.5 min, T= 95 ℃, t=17.4 min, and the storing period under this treatment can reach 120 days. In conclusion, reasonable drying degree, sterilization conditions and storage temperature can effectively improve the quality of inoculated rice mash grass carp during the storage. This paper could practically promote the processing and utilization of grass carp and improve the quality of sterilized ready-to-eat aquatic products.