Ultra-high Pressure Process Technology Of Fresh Grass Fish Fillets

Grass carp is one of the "four major domestic fish" which is freshwater aquaculture in China.Its meat quality is tender and delicious with fewer bone spurs,fast growth,and large annual output.It is a kind of economic fish with high nutritional value.The primary way to trade grass carps is fresh sales in China.Plenty of grass carps die in the process of transportation and storage,causing abundantly economic losses due to decay and other reasons.Because of large peculiar smell happens when slaughtering live fishes,it is inconvenient to sell in supermarkets and groceries.Meanwhile,the youngers are unwilling to go to the fish markets which have the bad smell.This is a serious barrier to obstruct the expansion of the fresh fish market and the development of aquaculture.It can only hold their fresh for one day now if putting into the market the slaughtered fishes,because of non-bactericidal and the sales period is very short.As usual,it needs more than three days to make the fish from fisheries to the consumer's table.To avoid changing meat's quality,the fresh carcass cannot heat pasteurized carcasses though,so only for aiming to the advantages of spoilage bacteria to do moderate non-heat bacteria treatment.In this paper,the research object is the fresh grass carp fillets.Using ultra-high pressure technology to process them,under the precondition of ensuring the promotion of meat quality and effective sterilization.Optimizing the processing conditions and extend the fresh texture of grass carps is to find the best tasting period at different storage temperatures.The following parts are the main findings:1.enhances meat quality of carp fishes.The results showed that the hardness,elasticity,cohesion,and chewing of grass carp fishes increased with the development of treatment pressure at room temperature.After ultra-high pressure treatment,the water holding capacity of grass carp fishes increased to 29.65%.After simulating gastro gavage and in vitro digestion,the digestibility of fresh grass carps treated with ultra-high pressure increased up to 34.74% and 49.8% respectively.The sensory evaluation of grass carp fingerlings under different pressures showed that the ultra-high pressure treatment could'nificantly improve the softness characteristics of grass carp fishes,with the highest score of sensory evaluation of grass carps treated with 200 MPa.2.Ultra-high pressure fresh grass fish fillets for the best processing technology for the treatment temperature is 5 ?,the processing pressure is 200 MPa,dwell time is 10 min.The effects of a single factor on the bactericidal effect of grass carp fishes were investigated.The color changes of grass carp fishes under the different pressures were also measured.The results showed that the treatment pressure,dwell time and treatment temperature had significant effects on the bactericidal effect of fresh grass carp fillets.The color of grass carp fishes treated with the pressure above 200 MPa changed seriously,with the similar cook thoroughly appearance.By reducing the treatment pressure and adding fresh liquid treatment,it can achieve a stable bactericidal effect.Through orthogonal experiments were optimized to get the processing parameters of ultra-high pessure processing temperature of 5 ?,processing pressure of 200 MPa,holding time was 10 min.And through the validation test and sensory evaluation to determine the conditions for the best processing technology of ultra-high-pressure fish llet.3.The best tasting periods of ultra-high-pressure.Carps under storage conditions of 4 ? and ice temperature were 3 days and 7 days,respectively.The results showed that the ice-cream temperature of grass carps was determined to be-1.20 ?,and the grass carps cured at 5 ?,200 MPa and 10-min holding time were placed at 4 ? and stored ice temperature from-1.20 ? to 0 ?.The best tasting period of fish meat in the experimental group was 3 days at 4 ?,and the best tasting period of fish meat in the experimental group was 7 days.In the best taste of the period,there was no deterioration of the phenomenon of rancidity.The total number of colonies ? 6log CFU / g,total nitrogen volatile base ? 20 mg / 100 g,health requirements in line with GB2733-2015 "fresh and frozen animal aquatic products hygiene standards".