Study On The Effect Of Residue On The Quality Of Sake Lees

Sake lees fish is an indispensable dish on the table in Jiangxi,especially in autumn and winter.The sake lees fish wine is rich in aroma,salty and suitable,and has a long-lasting aftertaste.Fermentation of traditional sake lees fish is usually carried out in fermentation tanks when the temperature is low.However,the cooking temperature,cooking time,koji dosage,sterilization temperature,etc.of sake lees fish in the process of sake lees will all affect the quality and flavor of sake lees fish products.In this paper,the effects of the change of the spoilage temperature and the brewing time during the spoiling process were studied,as well as the free amino acid content,fat oxidation and flavor changes of sake lees at different stages of the spoilage.The study of the quality changes of sake lees under different factors aims to provide a theoretical basis for improving the industrial production of sake lees.(1)The effect of the bad cooking temperature on the quality characteristics of sake leesThe quality characteristics of sake lees were compared by the difference in the cooking temperature(4℃,8℃,12℃,16℃,20℃,25℃).The results showed that L*(brightness)gradually decreased,a*(redness)value and b*(yellowness)value gradually increased at 6 temperatures,and the L* value of sake lees on the 18 th day at 25℃ was the smallest,48.60-50.12,and the a* value was the largest,8.03-9.99,and the hardness,viscosity and chewiness of color gradually decreased,and the elasticity gradually increased.The pH value gradually decreased,and the pH of sake lees fish reached a minimum value of 5.43 on the 15 th day at 25℃,and the TCA-soluble peptide gradually increased,and the TCA-soluble peptide in fish meat reached 10.33 mg tyrosine/g at 4℃ for 18 days,but at 25℃,the content of TCA-soluble peptide in fish meat was the highest on the 18 th day,reaching 11.9 mg tyrosine/g sample.The content of amino acid nitrogen gradually increased,and the content of amino acid nitrogen in sake lees fish at 25℃ was the highest,reaching a peak of 0.37% on the 15 th day.Muscle fibrillar protein levels increase gradually.Because the lees fish meat at a cooking temperature of 25℃ is too soft and rotten,it is not conducive to the subsequent study of flavor effects.Therefore,based on the physical and chemical indicators,the color and texture quality of sake lees fish at a residue temperature of 20℃ are the best,so 20℃ is selected as the optimal temperature for the production of sake lees fish lees.(2)Changes in fat oxidation of sake lees during the fermentation periodThe changes of fat oxidation of sake lees under different bad days(3d,6d,9d,12 d,15d,18d)at 20℃ were studied,and the fat oxidation process of sake lees was explored.The results showed that the content of TBARS increased with the increase of the number of bad days,and the content of TBARS was 0.242mg/kg on the 3rd day,and the content of TBARS(thiobarbituric acid)increased rapidly on the15th-18 th day,reaching 0.54mg/kg on the 18 th day.The POV content increased first and then decreased,and the growth rate was slow,and the POV content was 0.027meq/kg on the third day and reached 0.035 meq/kg on the 18 th day.The content of crude protein and salt-soluble protein showed a similar trend of decrease,and the crude protein content decreased from 55.14% on the 3rd day to 53.93% on the 18 th day.The salt-soluble protein decreased from 49.17% on day 3 to 41.69% on day 18;Histamine content gradually increased,from 10.46 mg/kg on the 3rd day to 60.27mg/kg on the 18 th day.The content of reducing sugars first increased and then decreased,reaching a peak of 3.9% on the 12 th day.With the prolongation of the fermentation time,the protein degradation is severe,so that the myofibrils in the tissue structure of sake lees gradually increase the gap and the compactness is poor with the increase of the number of days of waste,and the arrangement disorder between myofibrils intensifies.(3)Changes in the taste and flavor of sake lees fish during the production periodThe taste and flavor of sake lees fish will change to varying degrees at different times during the production period,and the taste of sake lees fish comes from the degradation of its proteins,and the flavor comes from the two main processes of protein and fat oxidation.In this section,the comprehensive analysis of free amino acids,free fatty acids,gas chromatography-mass spectrometry(GC-MS)and electronic tongue instruments showed that the total amount of free amino acids increased first and then decreased with the extension of the spoilage time,and the total amount reached a maximum of 24.9g/100 g on the 9th day.The content of unsaturated fatty acids gradually increased with the extension of the spoilage time;The electronic tongue can effectively distinguish the sake lees fish with different cropping times;Gas chromatography-mass spectrometry(GC-MS)analyzed the flavor substances of sake lees fish at different cropping times,and the results showed that the total number of flavor substances in the sake lees fish increased first and then decreased during the fermentation process,and reached the maximum number of species on the 9th day.Based on the fat oxidation changes of sake lees fish under different days,it was determined that the quality of sake lees fish was the best under the residue on the 9th day of 20℃,and the total amount of free amino acids and flavor substances reached the maximum value.