Study On Tuna Biological Preservation Technology

Tuna’s meat tender and delicious, is rich in nutrition, it’s the recommended healthcate by International Nutrition Society. Due to the tuna live in no pollution abyssal area, itis took green, safe and pollution free food, it is domestic and abroad consumers’ favor. Themost common edible method is tuna sashimi, it requires the flesh shall with high fresh. Atthe moment, the transportation and sales adopt cryogenic freezing, it exist high energy andcost, also freezing process will seriously affect the edible quality. If it can prolong thepreservation length with the premise of keep flesh quality, then it can save a mass ofenergy and cost to have the enterprise to profit. Therefore, tuna’s refresh technologybecame the key point of the research. Biological preservation skill with safe, sackless, noharm and efficient advantages, and it provides the possibility of the research of tuna refreshtechnology.Based on above stated reasons, this article takes yellowfin tuna as the researchobjective, directs to tuna freezing special spoilage organisms and main pathogenic bacteria,screened out three biological preservatives (Tea Polyphenol, Water-soluble Chitosan,Nisin). By testing tuna flesh’s physicochemical index, freshness index and sensorycharacteristics determined the three preservatives best consistence. Apply response surfacemethods optimized the three preservatives proportioning, mainly evaluated the effect ofrefreshing from the aspects of physicochemical index, freshness index, sensorycharacteristics and nutrition. And further researched under different freezing temperaturesthe effects of preservation, provided theory basis for tuna’s quality, prolong preservationlength and save energy.Main researched results as below:1. Per inhibition zone experiment, screened out Tea Polyphenol, Water-solubleChitosan, Nisin as tuna flesh’s biological preservatives. Under-18Centigrade degree,compared with blank group, fleshes which immersed by Tea Polyphenol, Water-solubleChitosan, Nisin with outstanding preservation length extension, all of the threepreservatives can make TVB-N value, pH value, MetMb value at a relatively low level toimprove flesh’s tinct a*value, hardness and keep elasticity. Tea Polyphenol, Water-solubleChitosan, Nisin as simplex biological preservative best consistence respectively is6g/L,15g/L,0.4g/L.2. According to Box-Behllken central composite design theory, assured thatcompound biological preservative best portioning is Tea Polyphenol6.55g/L, Chitosan16.05g/L, Nisin0.46g/L, with this scale can arrive the best effect. Compound biological preservative can control TVB-N value effectively, it can keep the freshness class atgrade two during the storage and achieve the purpose of refresh. Relieving the speed ofdegradation of the tuna and keep pH value steady. Putting off rate of oxidation, keep theMetMb steady. Compound biological preservative also can maintain tuna original tinct&hardness and coherency well.3. Make researches of different freezing temperatures compound biologicalpreservative refresh effects, summed out that immersed compound biological preservativefleshes with notable differences with different freezing temperatures (P<0.05). Compoundbiological preservative at-18and-25centigrade degree can both lengthen one month’spreservation length. No observable effect at-55centigrade degree.