Refrigeration Preservation Technology Of Scomber Japonicus

Scomber japonicus as a kind of pelagic fish in warm water has stronger exercise ability and mainly lives in the western Pacific coast which has the most productive in the East China Sea. The annual amount of fishing in this area is about 50 million tons, especially plays an important role in the local fishermen business. This paper is about the cold fresh waters preservation, the ice storage preservation, the double helix spiral freezing process, and the cold chain compared to on-board and shore frozen Scomber japonicus quality, which can improve the quality and have practical significance on the optimization pre-treatment. The main conclusions in this paper were as follows:1. The Study of cold water preservation technology of Scomber japonicus in water boat. The results showed that: early winter Scomber japonicus was stiff at 18 h, full rigor at 24 h, start rigor at 96 h; the stiff and full time by cold seawater is at 18 h and 24 h, maintain full-time stiff about 84 h, 108 h start rigor. Sensory indicators showed a falling trend, and p H firstly decline after the rise, the electrical conductivity and K value showed an increasing trend within 0-108 h, which indicated that cold seawater treatment can slow the degradation of nukcleolus, inhibition of endogenous enzyme activity and microbial growth, better effect on the quality of fish.2. The Study of iced water preservation technology of Scomber japonicus in processing ship. The results showed that: sensory indicators showed a falling trend, K value, total volatile nitrogen(TVB-N) and aerobic plate count(APC) showed an increasing trend within 0-84 h. During storage time, K value, TVB-N and APC variation are in line with kinetic level, the reaction rate increases with increasing temperature, and establishing the kinetic model. According to the actual requirements, selecting the appropriate storage temperature and quality indicators to provide a theoretical basis for predicting shelf life.3. The Study of the fresh Scomber japonicus with the double helix speeding freeze. The results showed that: using 30 mg/kg sodium hypochlorite solution 15 min at 5 ℃, rinsing 30 s, draining 2 min is the best quick-frozen reduce 35.43% of bacteria compared to the control before treatment. The parameters of double spiral freezer unit is-33.1 ℃ for inlet temperature,-31.9 ℃ temperature for the discharge port, and belt speed for 8.10 M/min. Center temperature is lowed from 15 ℃ to-32 ℃, freeze cycle for 18 min, which is shorter than the refrigerator with 190 min. The hardness, elasticity, cohesion, water holding capacity, salt-soluble protein content, Ca2+-ATPase activity and SH content were higher than the refrigerator freezing, APC was less than the refrigerator freezing, which described the double spiral freezer was more effective on quality assurance of frozen mackerel.4. The comparation of quality influence of old chain between the on-board and shore frozen. The results showed that: The water holding capacity, sensory evaluation, actomyosin soluble salt, Ca2+-ATPase activity and SH content all had a falling trend, TVB-N, histamine and TBA were growing with slow early growth and rapid growth later. Getting the relationship among ship acceptability, storage temperature and time by drawing a ship frozen Scomber japonicus T.T.T curve and the rate of decline in quality, which provided a theoretical basis for the quality control of ship frozen.