Study On Processing Technology Of Skipjack Soft Canned Food

Skipjack tuna is a protein-rich, low fat content, reasonable amino acid ratio, have a high content of unsaturated fatty acids and minerals of fishery resources, abundant dark meat of skipjack tuna, is not conducive for sashimi, but processed into canned skipjack has great market competitiveness.In this paper, study object is frozen Skipjack tuna,first select three kinds of deacidification agents, through single factor and orthogonal experiments to determine the best deacidification conditions of each deacidification agent,then three kinds of deacidification agents compound,determined the optimal deacidification formulation;and secondly the Skipjack tuna quality changes and changes in the characteristics of toxic substances histamine during the heat treatment were studied; and then studied the processing of soft canned of Skipjack tuna, Finally,Using first order kinetic model and Arrhenius equation predicted the shelf life of two kinds of canned Skipjack tuna developed in storage at room temperature. The results are as follows:Through orthogonal experiment of each deacidification agent(sodium hexametaphosphate, disodium hydrogen phosphate, sodium tripolyphosphate) to determine the best deacidification conditions of each one deacidification agent.Best deacidification conditions for sodium hexametaphosphate is: the mass fraction of 0.6%, deacidification time was 4h, deacidification temperature is 50 ?, solid-liquid ratio of 1: 3; optimal deacidification conditions for disodium hydrogen phosphate is : mass fraction of 0.7%,deacidification time was 4h, deacidification temperature is 40 ?, solid-liquid ratio of 1: 5,;optimal deacidificationconditions for sodium tripolyphosphate is: the mass fraction of1.0%, deacidification time 4h, deacidification temperature is 30 ?, solid-liquid ratio of 1:4. Secondly, the three deacidification agent compound used in accordance with the results of single factor experiments to determine the best formulation of complex deacidification agents, namely: the mass fraction of sodium hexametaphosphate is 0.7%,the mass fraction of disodium hydrogen is 0.7%,the mass fraction of sodium tripolyphosphate is 1.0%,after deacidification in this conditions, pH value is 6.93,sensory score is 4.94, the fish almost no sour.During the heat treatment, the Skipjack tuna quality changes and changes in the characteristics of toxic substances histamine were studied.The results showed that: with the central temperature rising, the length of skipjack shortened first quickly and then slowly,up to 24.56% at 80°C; the width expanded first and then shrank, the expansion rate is12.15% at 80°C; the thickness expanded all the time, at 80°C is 22.17%; cooking loss are increasing; variation tendency of hardness and chewiness were roughly same,the elasticity has been reduced, cohesion fluctuated greatly, but overall increased. The salt-soluble proteins, alkaliinsoluble protein, water-soluble protein decreased gradually, and no water-soluble protein was detected at 60°C,alkali-soluble protein and non-protein nitrogen increased gradually; acidity of skipjack meat was increasing. Meanwhile,histamine contentof skipjack during heat treat was studied. The results indicated that the content of histamine increased after heating, and the higher the histamine content of starting material, the more significant increase after cooking.Process of soft canned Skipjack tuna: the order of four main factors that affect the qualiy of spicy canned skipjack tuna quality is: paprika> red oil> salt> pepper, the optimal formulation of spicy canned Skipjack tuna:Pepper powder added in an amount of 2%, chili powder added in an amount of 3%,red oil was 2%,salt added in an amount of 2.5%. the order of four main factors that affect the qualiy of sweet and sour canned skipjack tuna quality is: ketchup>white vinegar> White sugar> salt, the optimal combination of sweet and sour canned Skipjack tuna is:added in an amount of 35% ketchup, add white vinegar an amount of 1.5%,addition level of 5.5% of white sugar, salt added in an amount of 1.5%.Using first order kinetic model predicted the shelf life of two kinds of soft canned skipjack. According to measured histamine content and peroxide value at different temperatures and times,Calculated the change rate constants k value of each index, thus obtained the Arrhenius equation,the correlation coefficient of the regression equation correlation coefficient R2 of the regression equations were more than 0.9,According to the formula of first order kinetic model to give the shelf life prediction model of spicy soft canned Skipjack tuna and sweet and sour soft canned skipjack tuna, drawn relative error between spicy bonito in the range of-7.55%-5.62%, and relative error of sweet and sour canned skipjack predicted shelf life and real shelf life in the range of-7.45%-5.88%,and the error are within the acceptable range, indicating that the shelf life prediction model constructed with high fitting accuracy. Calculated by the prediction model, the theoretical value of spicy bonito shelf respectively 98 d at 25?, 76 d at 30?, the theoretical value of the shelf life of sweet and sour bonito were 115 d at 25?, 87 d at 30?.