Study On The Development And Flavor Of Fermented Semi-Dried Sea Bas

Sea bass has rich nutrition and is a great source of high quality protein required by the human body.In this paper,with sea bass as raw material,a fermented semi-dried sea bass product was developed which has unique flavor and can be preserved easily.The curing,dehydration,fermentation and drying processes of sea bass processing were investigated through single-factor and optimization experiments to obtain the optimal processing parameters,.The changes of microbial communities during the fermentation and volatile flavor components during the processing of sea bass were investigated.In addition,the shelf life of the products was predicted.The specific study contents and results are as follows:The ultrasonic-assisted curing process was optimized by single-factor experiments and response surface experiment with Na Cl content and sensory score as indicators.The optimal process parameters for curing were obtained as follows: brine concentration was19%,ultrasonic power was 390 W,and ultrasonic time was 90 min.The dehydration conditions of sea bass were determined by using the sensory score as an index: temperature 50°C,time 6.5 h,and moisture content of 50% of the fish after dehydration.The fermentation process parameters were determined by single-factor and orthogonal experiments using amino nitrogen content,total acid content and sensory score as indicators as follows: the amount of wine malt added was 1%,the fermentation temperature was 30℃ and the fermentation time was 7 d.The changes in the overall flavor of sea bass under different fermentation times were investigated by using electronic nose.The results showed that the overall flavor of fish at 1 d of fermentation was distinctly different from other samples,and the flavor changes of fish at 5 and 6 d of fermentation were relatively small.The changes of microbial community of sea bass during the fermentation process were explored by 16 s r RNA high-throughput sequencing.The results showed that the microflora of sea bass after fermentation differed from that before fermentation,and the firmicutes and proteobacteria were the main microflora during the fermentation process.The effects of different drying methods and moisture content on the sensory scores of fermented semi-dried sea bass were analyzed,and microwave drying(400 W)was determined to be the best drying method with a moisture content of 40% at the end of drying..The changes of volatile flavor substances during the processing of fermented semi-dried sea bass were determined using a gas chromatograph,and the results showed that a total of 85 flavor substances were detected during the processing.The main flavor substances in raw sea bass were hydrocarbons,aldehydes and aromatics;the flavor components of sea bass after curing were mainly aldehydes and aromatics;the volatile flavor substances after dehydration were mainly aldehydes and aromatics;after fermentation,alcohols,esters and aromatics contributed more to the flavor of sea bass,and the secondary drying increased the relative content of ester compounds.The shelf life of fermented semi-dried sea bass at 20°C was calculated using Arrhenius equation as 26 d.