中文摘要：
米酒历史源远流长,因其酿造工艺简单,酿造出来的口味香甜醇美,含酒精量极低,所以深受广大人民的喜爱。米酒的酿造过程是一个非常复杂的微生物共同发酵的过程,主要作用机理是根霉、酵母和细菌(主要是乳酸菌)等几种主要微生物的糖化、酒化、酸化、酯化等过程的协同进行,目前乳酸菌在米酒发酵过程中所起的作用的研究不多,米酒在多菌种共同发酵的过程中乳酸菌是非常重要的一种,本文对米酒曲中乳酸菌进行分离鉴定,分析乳酸菌在米酒曲中的多样性。另外,米酒液态发酵技术的研究,对于工厂降低生产成本以及提高米酒生产效率有重要的意义。本文通过单因素实验与正交试验研究,设计酿造条件的组合实验来优化米酒液态酿造工艺,建立起米酒液态酿造技术的基础。利用气相色谱技术和高效液相色谱技术,对液态酿造法酿造出的米酒进行风味物质的测定,初步建立米酒液态酿造法米酒品质的衡量指标。初步探究乳酸菌对米酒风味的影响,并对该酒样进行气相色谱分析和液相色谱分析得出相关参数,为之后的混合发酵提供理论基础。本研究通过传统稀释平板涂布针对八种米酒曲中乳酸菌进行分离筛选与鉴定。在稀释平板涂布法共分离和鉴定得11株乳酸菌,归为3个属,3个种,其中乳杆菌属3株,片球菌数7株,魏斯氏菌属1株。具体为:戊糖片球菌(Pediococcus pentosaceus)、发酵乳杆菌(Lactobacillus fermentum)、食窦魏斯氏菌(Weissella cibaria)。对所获得的菌种与实验室所存的植物乳杆菌(Lactobacillus plantarum)进行耐温性、耐酸性和耐乙醇实验,对比其在米酒发酵环境中的耐受性,结果表明植物乳杆菌(Lactobacillus plantarum)在乙醇浓度为7%和p H为3.5的酸性环境有较好的耐受性,对于改进米酒发酵工艺具有重要的参考价值。通过研究,确定了对米酒酿造影响较大的工艺条件是:接种量、菌种比、发酵时间、发酵温度、料水比。选择影响米酒液态酿造的主要工艺条件进行不同的组合试验。其中接种量水平因素为: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;菌种比(扣囊腹膜酵母zcr3-1:异常威客汉逊酵母zcr3-2:酿酒酵母AQSC)水平因素为:1:1:1、2:1:1、1:2:2;发酵时间水平因素为:前发酵1天、后发酵3天,前发酵2天、后发酵2天,前发酵3天、后发酵1天;发酵温度水平因素为:30℃-25℃、28℃-25℃、25℃-20℃;料水比水平因素为:1:3、1:3.5、1:4。利用单因素实验和正交试验确定米酒液态发酵最优工艺为:料水比在1:3.5,接种量在1×10~6cfu/m L,菌种比(zcr3-1:zcr3-2:AQSC)在2:1:1,前发酵温度25℃下发酵2天,后发酵温度20℃下发酵2天。通过测定最优米酒液态酿造法的米酒的理化指标和风味物质的含量,初步确定了判断米酒液态酿造法米酒品质的衡量标准,最优发酵工艺为料水比在1:3.5,接种量在1×10~6cfu/m L,菌种比在2:1:1,前发酵温度25℃下发酵2天,后发酵温度20℃下发酵2天,经此工艺发酵后的米酒中酵母数量能达到7×10~7cfu/m L,p H范围最适为3.7-4.0,最优组合酿造出的米酒酒精度可达到4.11%vol,还原糖浓度可达到150.87g/L,乙酸乙酯浓度达到6.9 mg/L,正丙醇浓度达到4.47 mg/L,测得乳酸浓度622 mg/L,乙酸浓度212.47 mg/L,琥珀酸浓度647.46 mg/L。对此组合的酒样进行感官评价,感官评分最终结果为95.0分。初步探究乳酸菌对米酒品质的影响,首先通过添加不同乳酸菌数量与复合酵母菌(zcr3-1,zcr3-2,AQSC)的比例(乳酸菌数量:复合酵母菌数量=1:2,1:5,1:10),测定乳酸菌与复合酵母菌的数量变化,并且对各酒样进行感官评分,得到添加的乳酸菌为植物乳杆菌(ZR-1)且添加的ZR-1数量与酵母菌数量比例为1:10时,米酒感官评分最高为95.4。通过观察乳酸菌与复合酵母数量变化得出:MJ5-1(戊糖片球菌)与复合酵母共同发酵对复合酵母有一定的增生作用,在米酒的发酵过程中复合酵母菌增多导致发酵作用会有一定的阻碍,影响米酒的口感;GS-1(发酵乳杆菌)与复合酵母相对生长较好的比例在1:5,前发酵GS-1对复合酵母的生长有一定的促进作用,但是后发酵复合酵母的生长受到一定的抑制。ZR-1与复合酵母在低比例(1:10)下共同发酵有一定互生作用,也会使各菌种间发酵的协调更加切合,从而改善米酒口感。对添加ZR-1的米酒样进行相关理化指标、气相分析与液相分析得到:添加ZR-1进行发酵的米酒p H为3.92,还原糖浓度为120.13 g/L,乙醇浓度(%v/v)4.55,乙酸乙酯浓度为6.73 mg/L,正丙醇浓度为5.46 mg/L,琥珀酸浓度为524.47 mg/L,乙酸浓度为218.13 mg/L,乳酸浓度为1255.77 mg/L。其中乙酸和乳酸这两种有机酸有较大的增幅,能更加丰富米酒风味以及提高米酒营养。
英文摘要：
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
