Study On The Effect Of Processing Technology On The Quality Of Air-dried Gold Pomfret Products

As one of the traditional Chinese flavor food,dried fish products are deeply loved by consumers because of their unique taste and flavor.Gold pomfret as one of the aquaculture species,is a kind of nutrient-rich marine fish with medium to high grade quality.The golden pomfret was originally positioned as an export product and was mainly sold to North America such as the United States and Canada in the form of frozen fish.As a new and valuable economically farmed fish in the coastal areas of China in recent years,the scale and output of the gold pomfret culture have increased year by year,and the price has begun to decrease,gradually reaching the level of mass consumption.In the main domestic market,consumption is still mainly in the vicinity of production.When the export meets difficulties,the domestic sale’s pressure is relatively large,causing large changes in market price fluctuations and affecting the income of the fishermen.Processing air-dried golden pomfret products combining modern technology can not only prolong the preservation time,solve the dull of sale,but also enrich the sale’s way of products and increase the income of fishermen.Domestic and foreign scholars had reported a lot on the processing technology of fish pickling and air drying,but there was little report on the quality changes in different parts of air-dried golden pomfret products during the process.In this study,the frozen golden pomfret was used as raw material,the salt concentration,pickling temperature,air drying time and air drying temperature were tested as single factors,and the sensory evaluation was used as an indicator.The optimum processing conditions were obtained by orthogonal test adopting the wet-curing process.Then different processing points were selected to detect the changes of edible quality,lipid oxidation and protein oxidation,and the related indices of the gold pomfret back and belly meat were compared,to provide a theoretical basis for the practical processing.The main conclusions are as follows:(1)In the processing of air-dried golden pomfret products,It was found that the salt concentration and air drying temperature had very significant effects on the sensory scores of the golden pomfret products,the air drying time had a significant effect,and the curing temperature has no significant effect.The final optimum processing conditions were curing temperature of 10℃,salting salt concentration of 8%,air drying temperature of 40 ℃ and air drying time of 72 h.(2)During the processing of dried golden pomfret products,the moisture content and water activity of the golden pomfret and the fish belly meat decreased continuously,the pH value decreased first and then increased,and the total nitrogen content did not change significantly during the processing.The types of volatile flavor substances were increasing,the L*value and the b*value were gradually increasing,and the a*value was first increased and then decreased.After the electronic tongue detection,data analysis showed that,for the golden pomfret back and belly meat during processing,delicate flavour gradually increased and the bitterness gradually decreased,which was conducive to the production of good taste and good eating quality.The changes of physical and chemical indicators in the processing of the golden pomfret were basically the same for back and belly meat,however,there were significant differences in the △E value,hardness,bitterness,astringency,volatile flavor and free amino acid content after air drying for 72 hours.(3)During the processing of air-dried golden pomfret products,the POV value,carbonyl value and TBARS of the golden pomfret fish back and fish belly meat were the same-Compared with the raw materials,the MUFA and PUFA in the fatty acid composition of fish back and fish belly meat showed a significant decrease(p<0.05)with the processing progress,indicating that the curing and air drying caused the oxidative decomposition of unsaturated fatty acids.The lipid oxidation related indexes of fish back meat were higher than that of fish belly meat.At the same time,the PUFA content in the fatty acid composition of fish back meat was higher than that of fish back,which was consistent with the rule that PUFA was oxidized more easily during pickling and air drying.The degree of lipid oxidation of the golden pomfret fish back meat and the degree of lipid oxidation of the fish belly meat during processing were different.(4)During the processing of air-dried golden pomfret products,the carbonyl value,hydrophobicity and total sulfhydryl content of the fish meat and fish belly protein had the same trend,the carbonyl value and hydrophobicity increased,and the total sulfhydryl content decreased.During the pickling stage,some protein underwent oxidative hydrolysis.During air drying,protein oxidation was more obvious.After the processing,the difference of protein oxidation between the golden pomfret back and belly meat was not obvious.