Study On The Wine Making Process And Quality Formation Of Sweet Potato Vermicelli Residu

HSFTZ is a defective product that occurs during the production and processing of sweet potato starch products using sweet potato starch as raw material.This paper studied the preparation process of HSFTZ liquid fermentation and solid fermentation,and analyzed the flavor of the two wines.Next,the process and mechanism of flavor formation of HSFTZ liquor by solid-state fermentation are interpreted from the perspective of microorganisms and flavor during fermentation.The main research results are as follows:(1)Analysis of raw materials shows that HSFTZ is mainly composed of starch,with a starch content of up to 94.76 ± 0.63 g/100 g,and the rest being ash content of 0.31 ± 0.12 g/100 g,protein content of 0.05 ± 0.01 g/100 g,and fat content of 0.87 ± 0.35 g/100 g.The water holding capacity and rehydration characteristics of HSFTZ are 248.24 ± 9.50% and 112.33 ± 4.05%,respectively.The solubility and swelling degree reach their maximum values at 90 ℃,which are14.7 ± 1.05% and 13.31 ± 2.21%,respectively.The physical and chemical indexes of the seven rounds of preparation of grains for Maotai flavor Baijiu,another raw material required for HSFTZJ solid-state fermentation process,are as follows: water 56.11 ± 0.65 g/100 g,starch 9.83 ±1.44 g/100 g,acidity 4.23 ± 0.31 g/L,reducing sugar 0.39 ± 0.17 g/100 g.The above indicators provide design basis and data support for the subsequent two fermentation processes.(2)The liquid and solid state fermentation processes of HSFTZ were optimized.Liquefaction process in liquid fermentation: the ratio of material to liquid is 1:5,the temperature is 90 ℃,the amount of liquefied enzyme added is 750 U/g,and the liquefaction time is 20 minutes.The optimal fermentation process through orthogonal experiments was as follows: material liquid ratio1:5,yeast addition 1.5%,temperature 30 ℃,time 11 days.The scale-up experiment results showed that the optimized liquid fermentation process had a fermentation cycle of 11 days and a liquor yield of 85.28%.Compared to the original production process that only relied on uncooked starter fermentation without enzymatic hydrolysis(production cycle of 90 days and liquor yield of60%),the fermentation cycle was shortened by more than 87%,and the liquor yield of 50% vol liquor was increased by more than 20%.In the solid-state fermentation process,water is added first and then crushed raw materials are added according to a material water ratio of 1:0.8.After fully stirring and soaking,the raw materials and mixed grains are crushed and fluffy again.The raw materials and mixed grains are evenly mixed according to 1:9.Stacked fermentation for 23 hours and fermentation in the cellar for 30 days resulted in a liquor yield of 17.24%,with a distinct aroma of soy sauce and fermented grains smelled,providing a certain reference for the development of new products of HSFTZ liquor.(3)The objective and subjective evaluation of the flavor of the two wines was conducted through HS-GC-IMS and sensory evaluation.HS-GC-IMS identified a total of 34 volatile metabolites in two types of liquor,including 21 flavor substances in liquid fermentation liquor and33 flavor substances in solid fermentation liquor.Butyl 2-methylbutyrate is a unique ester substance in liquid fermentation liquor,while solid fermentation liquor is dominated by ester substances,with a total of 10 types of ester substances,followed by 4 alcohols,4 alkenes,4aldehydes,and 1 other type of substance.The sensory evaluation of preference type was conducted using a unilateral paired comparison test,and the results showed that 23 of the 30 subjects preferred the flavor of solid-state fermented wine;Analytical sensory evaluation adopts the comprehensive evaluation method of fuzzy mathematics,and the results show that the fuzzy matrix calculation results obtained by the four synthesis operators have some differences,but the distinction between the two evaluation sets of Level I and Level III is significant,which can prove that the flavor of HSFTZ wine prepared by solid-state fermentation process is better than that of liquid fermentation process.(4)The HSFTZ fermented grains produced by solid-state fermentation were studied using high throughput sequencing technology.The law of community succession shows that there are 4dominant bacterial phyla(Proteobacteria,Firmicutes,Actinobacteriota and Bacteroidota)and 3fungal phyla(Ascomycota,Basidiomycota and Mucoromycota)at the phyla level;At the genus level,there are a total of 9 dominant bacterial genera(Acetobacter,Lactobacillus,Saccharopolyspora,Pseudomonas,Oceanobacillus,Virgibacillus,Pseudonocardiaceae,Kroppenstedtia and Bacillus)and 14 dominant fungal genera(Aspergillus,Candida,Issatchenkia,Pichia,Kazachstania,Penicillium,Byssochlamys,Monascus,Thermoascus,Wallemia,Leiothecium,Cyberlindera,Malassezia,and Thermomyces).The functional prediction results showed that during the entire fermentation stage,the metabolic function of bacteria was absolutely dominant at KEGG level-1,with the highest relative abundance at the intermediate stage of accumulation fermentation(FSGB),reaching 51.23%.At the KEGG Level-2 level,carbohydrate metabolism and amino acid metabolism are the main metabolic functions in five stages.At the MODE level,saprophytic and symbiotic trophic fungi dominate the entire process.At the Guild level,undefined saprophytes are absolutely dominant in the initial stage of accumulation and fermentation(FSGA),with 7 of the top 10 fungal functions accounting for saprophytic bacteria.(5)The volatile and nonvolatile flavor compounds in the fermented grains of HSFTZ liquor during the five stages of solid-state fermentation were analyzed by headspace gas chromatography ion mobility spectroscopy(HS-GC-IMS)and ultra high performance liquid chromatography tandem mass spectrometry(UHPLC-QE-MS)techniques.The results showed that a total of 50 volatile metabolites were identified in the fermented grains during the five stages of solid-state fermentation,including 8 esters,8 olefins,6 alcohols,6 aldehydes,5 alkanes,3 ethers,3 furans Three pyrazines,one acid,and seven other volatile metabolites.Based on the OPLS-DA model,a total of 51 nonvolatile differential metabolites were selected from metabolites with a secondary mass spectrometry score of>0.9(MS.2 score>0.9)in combination with VIP>1 and ANOVA P<0.05,including 10 organic acids,5 amino acids,6 fatty acids,5 esters,3 phenols,3 organic heterocycles,2 aldehydes,1 alcohol,1 ether,and 15 other substances.