| Rice wine has a long history.Because of its simple brewing process,the taste is sweet and mellow,and its alcohol content is very low,so it is deeply loved by the majority of people.The brewing process of rice wine is a very complicated process of microbial fermentation.The main mechanism is the synergy of saccharification,alcoholization,acidification,and esterification of several major microorganisms,such as rhizopus,yeast,and bacteria(mainly lactic acid bacteria).However,there is not much research on the role of lactic acid bacteria in the fermentation process of rice wine.Lactic acid bacteria are a very important type of rice wine in the process of co-fermentation of multiple bacteria.In diversity.In addition,the research of liquid rice high-efficiency brewing technology is of great significance for factories to improve rice wine production efficiency and reduce production costs.This article uses single factor experimental research and orthogonal experiments to design a combined experiment of brewing conditions to optimize the rice wine brewing process and establish the basis of rice wine liquid brewing technology.Using gas chromatography technology and high-performance liquid chromatography technology,the flavor of the rice wine brewed by the liquid brewing method was measured,and the quality indicators of the rice wine brewed by the liquid brewing method were initially established.The effects of lactic acid bacteria on the flavor of rice wine were explored,and relevant parameters were obtained by gas chromatography and liquid chromatography analysis of the wine sample,which provided a theoretical basis for the subsequent mixed fermentation.In this study,lactic acid bacteria in eight kinds of rice koji were screened and identified by traditional dilution plate coating.A total of 11 strains of lactic acid bacteria were isolated and identified by the dilution plate coating method and classified into 3genera and 3 species,including 3 strains of Lactobacillus,7 strains of Pediococcus,and 1strain of Weissella.Specifically:Pediococcus pentosaceus,Lactobacillus fermentum,Weissella cibaria.The obtained bacteria and Lactobacillus plantarum stored in the laboratory were tested for temperature resistance,acid resistance and ethanol resistance,and their tolerance in the rice wine fermentation environment was compared.The results showed that Lactobacillus plantarum has good tolerance in acidic environment with ethanol concentration of 7%and p H of 3.5,which has important reference value for improving rice wine fermentation process.Through research,it was determined that the process conditions that have a greater effect on rice wine brewing are:inoculation amount,strain ratio,fermentation time,fermentation temperature,and water-to-water ratio.The main factors influencing the rice wine brewing process were optimized experiments,and the main process conditions affecting rice wine brewing were selected for different combinations.The inoculation level factors are:1×10~7cfu/m L,5×10~6cfu/m L,2×10~6cfu/m L,1×10~6cfu/m L,5×10~5cfu/m L;strain ratio(zcr3-1:zcr3-2:AQSC)The level factor is:1:1:1,2:1:1,1:2:2;the factor of fermentation time is:1 day before fermentation,3 days after fermentation,2 days before fermentation,2 days after fermentation,before Fermentation for 3 days,followed by fermentation for 1 day.The factors of the fermentation temperature level are:30?-25?,28?-25?,25?-20?;the factors of the material-water ratio are:1:3,1:3.5,1:4.Using single-factor experiments and orthogonal experiments to determine the optimal fermentation process for rice wine liquid fermentation:the ratio of material to water is 1:3.5,the inoculation amount is 1×10~6cfu/m L,the strain ratio(zcr3-1:zcr3-2:AQSC)is 2:1:1,and the pre-fermentation temperature is 25?.Fermented for 2 days,followed by fermentation at 20? for 2 days.By measuring the physical and chemical indexes of rice wine and the content of flavor substances in the optimal rice wine liquid brewing method,the measurement standards for judging the quality of rice wine in the liquid wine brewing method were initially determined.The optimal fermentation process is the ratio of material to water at 1:3.5 and the inoculation amount at 1×10~6cfu/m L,the strain ratio is 2:1:1,the first fermentation temperature is 25? for 2 days,and the second fermentation temperature is 20? for 2days.The number of yeasts in rice wine after fermentation can reach 7×10~7cfu/m L,the optimum p H range is 3.7-4.0,the alcohol content of rice wine produced by the optimal combination can reach 4.11%,the reducing sugar concentration can reach 150.87mg/m L,the ethyl acetate concentration can reach 6.9mg/L,and the n-propanol concentration It reached 4.47 mg/L,and the measured lactic acid concentration was 622 mg/L,the acetic acid concentration was 212.47 mg/L,and the succinic acid concentration was 647.46 mg/L.Sensory evaluation of the wine samples of this combination,the final result of the sensory score was 95 points.Initially explore the influence of lactic acid bacteria on the quality of rice wine,first by adding the ratio of different lactic acid bacteria to the composite yeast(zcr3-1,zcr3-2,AQSC)(number of lactic acid bacteria:number of composite yeasts=1:2,1:5,1:10),measure the change in the number of lactic acid bacteria and composite yeast,and perform sensory scoring on each wine sample to obtain that the added lactic acid bacteria is Lactobacillus plantarum(ZR-1)and the ratio of the number of added ZR-1 to the number of yeast is 1:At 10 o'clock,the highest sensory score of rice wine is 95.4.By observing the changes in the number of lactic acid bacteria and compound yeast,it can be concluded that the joint fermentation of MJ5-1(Pediococcus pentosaceus)and compound yeast has a certain proliferative effect on compound yeast.In the fermentation process of rice wine,the increase of compound yeast will cause a certain obstacle to the fermentation and affect the rice wine.Taste;the relative growth ratio of GS-1(Lactobacillus fermentum)and compound yeast is 1:5.Pre-fermentation GS-1 has a certain promotion effect on the growth of compound yeast,but the growth of post-fermentation compound yeast is inhibited to some extent.ZR-1 and composite yeast co-fermentation at a low ratio(1:10)has a certain mutual effect,and will also make the coordination of fermentation between various strains more suitable,thereby improving the taste of rice wine.The related physical and chemical indicators,gas phase analysis and liquid phase analysis of the rice wine sample with ZR-1 were obtained:the p H of the rice wine with ZR-1 fermentation was 3.92,the concentration of reducing sugar was 120.13g/L,and the ethanol concentration(%v/v)4.55,ethyl acetate concentration is 6.73 mg/L,n-propanol concentration is 5.46 mg/L,succinic acid concentration is 524.47 mg/L,acetic acid concentration is 218.13 mg/L,and lactic acid concentration is 1255.77 mg/L.The two organic acids,acetic acid and lactic acid,have a larger increase,which can enrich the flavor of rice wine and improve the nutrition of rice wine... |
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