Study On Quality Characteristics Of Cultured Large Yellow Croaker And Fermentation With Red Vinasse

Since the breakthrough of aquaculture technology in large yellow croaker(Larimichthy scrocea),the yield has increased year by year,and it is one of China's traditional “four major aquatic products”.At present,the types of aquatic products are mainly divided into fresh products,frozen products,pickled products,dry products,smoked products,and vinasse products.Among them,vinasse products can combine plant protein and animal protein,have strong flavor and unique characteristics.The large yellow croaker has delicate meat,delicious taste,rich nutrition and easy absorption.It is an ideal raw material for processing aquatic products.However,the traditional vinasse large yellow croaker processing technology has a long production cycle and difficult to control quality.With the improvement of people's quality of life and healthy diet,we need to improve the processing technology.Therefore,this article takes the cultured large yellow croaker as the research object.First of all,the characteristics of cultured large yellow croaker as processing raw materials at different cultivation stages were studied.Secondly,the microflora and fermentation characteristics of dominant strains in red vinasse were studied.Finally,the effects of starter cultures and red vinasse fermentation on the quality of vinasse large yellow croaker were studied.The main findings are as follows:1.Analysis of raw material quality characteristics and evaluation of cultured large yellow croakerThe raw material of cultured large yellow croaker were used as research object,the nutritional composition,color,texture,and flavor characteristics of the raw material of large yellow croaker were analyzed and evaluated.The fat content of the large yellow croaker decreased during the three cultivation stages,which helped to prevent oxidation deterioration during processing.By the third month,it has good skin color,good elasticity,and cohesiveness that can keep the fish body intact during processing.Electronic tongue and electronic tongue can effectively distinguish the flavor differences of large yellow croaker at different cultivation stages.The overall richness profile of large yellow croaker increased at the sixth month.At the third month,the content of free amino acids in large yellow croaker was significantly increased,which had a positive effect on the good taste.The content of taste nucleotides fluctuated greatly due to the influence of the cultivation stages.IMP contributes most to the umami taste of the large yellow croaker.Analysis of the synergistic effect between free amino acids and nucleotides,The best umami taste at the sixth month.The content of polyunsaturated fatty acids was the highest at the third month.It can be speculated that the large yellow croaker may produce more volatile substances during heat treatment and storage.the volatile substances are mainly aldehydes,and the aldehydes are increased,alcohols are reduced during the cultivation process,with the most odoractive substances at the sixth month.With the extension of the cultivation time,the quality characteristics of raw material large yellow croaker improved.2.Study on microflora and fermentation characteristics of dominant strains in red vinasse from vinasse large yellow croakerThe microflora of red vinasse from the fermented large yellow croaker of Fujian specialty was analyzed,determine the physiological and biochemical characteristics,carbon source utilization of the dominant strains,and measure the acid production capacity according to the characteristic of lactobacillus.The growth curve of dominant strains under different environmental factors was measured,and the tolerance of dominant strains was evaluated using Gompertz model,then the fermentation properties were further determined.The results showed that Lactobacillus brevis and Saccharomyces cerevisiae were the dominant strains in the red vinasse samples by isolation and purification.Lactobacillus brevis produces acid and no gas produced.ornithine and lysine decarboxylase are negative and have lipase activity.Lactobacillus brevis and Saccharomyces cerevisiae can use substances such as sugars,amino acids,and esters,but the specific types of substrates used vary greatly.Lactobacillus brevis has good acid-producing ability,and can lower the p H to below 5.0 within 24 hours under the conditions of 25?,37? and 2% Na Cl.Lactobacillus brevis can grow under the condition of 2?6% Na Cl,which meets the requirements of common meat products for salt content,and it grows well at p H 4?7,exhibit good acid resistance.Saccharomyces cerevisiae can grow under the condition of 2?10% Na Cl,and can multiply rapidly in the presence of low-concentration Na Cl.Saccharomyces cerevisiae is not sensitive to acid,Under the condition of p H 4?7,there is no significant difference of lag period and maximum specific growth rate.In the presence of 1% lactic acid,it can promote the growth of Saccharomyces cerevisiae,and it has good tolerance to high lactic acid.The above characteristics show that the obtained Lactobacillus brevis and Saccharomyces cerevisiae are suitable for the production of fermented fish products.3.Study on the effects of starter cultures and red vinasse fermentation on the quality of vinasse large yellow croakerLarge yellow croaker fermented under the conditions of inoculation starter cultures and red vinasse were studied,determined the microorganisms,color texture profile analysis,p H,total acid,Amino nitrogen,total volatile basic nitrogen and sensory changes.The effects of starter cultures and red vinasse on the quality of fermented croaker were studied.The results showed that the inoculation of Lactobacillus brevis and Saccharomyces cerevisiae can inhibit the reproduction of miscellaneous bacteria,and the growth of the strains was well when inoculated into large yellow croaker.In addition,the addition of red vinasse can inhibit the proliferation and provide a safe environment for fermented large yellow croaker.The addition of compound starter cultures can increase the brightness of vinasse fish.The monascus pigment in red vinasse provides an attractive color for the large yellow croaker.After adding the compound starter cultures and red vinasse,the fermented large yellow croaker has a higher yellowness value and redness value.Lactobacillus brevis can increase the shear force of fermented large yellow croaker,and saccharomyces cerevisiae can increase the hardness,both of which contribute to the increase of cohesion and chewability.After adding compound starter cultures and red vinasse,the characteristics of soft and rotten were more obvious.Lactobacillus brevis can rapidly decrease the p H of fermented large yellow croaker,and red vinasee make the large yellow croaker have higher total acid content.The inoculation of Lactobacillus brevis can significantly increase the content of amino nitrogen and accelerate the fermentation,both Lactobacillus brevis and Saccharomyces cerevisiae can inhibit the spoilage and degradation during fermentation and inhibit the increase of total volatile basic nitrogen.Saccharomyces cerevisiae is beneficial to neutralize the pungent odor and make the overall flavor softer.The sensory score obtained by inoculate the compound strains and red vinasse was the highest.Fermentation to the seventh day had higher sensory quality of fermented large yellow croaker.