The Freezing-Thawing Stability Of Sturgeon And Its Frozen Prepared Product Development

Sturgeon is a cold-water fish,belonging to Osteopoda,Radiofibraceae,Scleroderma and Sturgeon.It is one of the earliest vertebrates in existence.It likes to live in cold and temperate waters with low salinity.It is the largest and longest-lived fish in freshwater fishes.It is called"living fossil"together with dinosaurs.China's sturgeon industry is gradually developing,the amount of sturgeon farming has made rapid progress,and the annual output has also increased year by year.Sturgeon meat is delicious,with high nutritional value and rich in protein and fat.Its main deep-processed product,caviar,is well received by consumers.However,the fishy smell of sturgeon meat is very serious,which seriously affects the development of sturgeon meat,resulting in the scarcity of sturgeon meat products,and the rich fat and protein content of sturgeon meat itself,which has a great impact on its preservation and transportation.To sum up,the utilization rate of fish meat is not high and the intensive processing products are few.In this paper,the effect of compound phosphates,salt and beta-cyclodextrin on deodorization of frozen hybrid sturgeon steak was studied.The better deodorization method was screened out by sensory evaluation and the volatile components were determined.Secondly,the effects of trehalose solution and compound phosphate solution with different concentrations on the texture,color,water holding capacity and cooking loss rate of fish fillets frozen and thawed 0,1,2,3,4 and 5 times were studied,and the optimum addition amount was obtained.On this basis,trehalose and compound phosphate were selected for orthogonal compounding.The texture,color,water holding capacity,cooking loss,thiobarbituric acid value,Ca²⁺-ATPase activity and scanning electron microscopy were used as indicators to study the quality changes of fish meat after freeze-thaw 0,1,2,3,4,5 times,and finally to determine the optimal compounding amount.Finally,the processing technology of frozen sturgeon fillet conditioning food was studied,and sturgeon meat products represented by sauerkraut fish flavor were developed.The results are as follows:1.Choice of Fish Deodorizing SolutionFish fillets were treated with clear water,3%salt solution,1%beta-cyclodextrin solution,1%compound phosphate+2%salt solution,2%compound phosphate+2%salt solution,3%compound phosphate+2%salt solution respectively.The sensory evaluation of raw fish fillets and cooked fish fillets were screened.Among the sensory evaluation of raw fish fillets,the treatment effect of 3%salt solution and compound phosphate+salt solution was better;in the sensory evaluation of cooked fish fillets,the treatment effect of 2%compound phosphate+2%salt solution was better.According to sensory evaluation,sturgeon fillets treated with 2%compound phosphate+2%salt solution were superior to other treatments in each index score,and the deodorization effect was the best.Then fish fillets were treated with 2%compound phosphate+2%salt solution.2.Effect of single antifreeze on quality of frozen sturgeon filletsFish fillets treated with different concentrations of trehalose and compound phosphoric acid solution were stored at-20^C for 0,1,2,3,4 and 5 times respectively.The texture,color difference,water holding capacity and cooking loss rate were measured.The results showed that the water holding capacity of fish fillets treated with different concentrations of trehalose solution decreased by 23.50%,17.30%,8.70%,15.80%and 10.90%respectively with the increase of freezing and thawing times.The cooking loss rates of fish fillets treated with trehalose solution at different concentrations increased by 15.10%,13.70%,8.70%,8.20%and 13.80%,respectively.With the increase of freeze-thaw times,the water holding capacity of fish fillets treated with different concentrations of compound phosphoric acid solution decreased by 20.80%,18.10%,16.80%,16.60%and 15.70%,and the cooking loss rates of fish fillets treated with different concentrations of compound phosphoric acid solution increased by 15.80%,15.60%,14.40%,13.80%,13.30%and 11.40%,respectively.In terms of texture and color difference,trehalose and compound phosphate can effectively delay the change of texture and color difference of fish fillets.Finally,2.5%trehalose solution and 3%compound phosphate solution are the best additions.3.Effect of Compound Antifreeze Agent on Frozen Fish FilletThe effect of compound antifreeze agent on the quality of sturgeon fillets during freezing and thawing was studied by compounding trehalose solution and compound phosphate solution.Compound antifreeze agent is superior to single antifreeze agent in water holding capacity,cooking loss rate,texture and color difference of fish during freeze-thaw period.Secondly,the thiobarbituric acid value of fish fillets treated with compound antifreeze agent was significantly lower than that of the blank group;the Ca2+-ATPase activity of fish meat decreased after freezing and thawing,but the Ca2+-ATPase activity of fish fillets treated with compound antifreeze agent was higher than that of the blank group,and the protein denaturation degree was lower;scanning electron microscopy showed that repeated freezing and thawing resulted in the microstructure of fish meat.From compactness to sparsity.Based on the above results,2.5%trehalose+3%compound phosphate solution can delay the quality change of fish during freeze-thaw period,which is the optimal dosage of compound antifreeze agent.4.Study on Processing Technology of Sturgeon Conditioned FoodThe technology of frozen food for sturgeon meat was studied.A variety of sturgeon meat products with different flavors represented by sauerkraut fish were developed.Through the pretreatment of sturgeon steak,such as slicing,cleaning and so on,the fish was deodorized with 2%compound phosphate+2%salt solution,salted with salt,liquor and other condiments,and finally the fish steak was made with self-made sauerkraut.Bone soup bags were packaged and frozen.Through sensory evaluation of self-made pickled vegetable fish and commercial Laotan pickled vegetable fish,Qiaotou pickled vegetable fish and seabed pickled vegetable fish,it is concluded that compared with market pickled vegetable fish,self-made pickled vegetable fish has little difference in taste,color and juiciness,and has a certain possibility of marketing,which can provide research direction for sturgeon meat development.