优质黄酒菌种、原料及其发酵工艺的研究

【作者】 夏艳秋；

【导师】 汪志君；

【作者基本信息】 扬州大学 ， 生物化学与分子生物学， 2004， 硕士

【摘要】 为了满足生产及市场需求，提高新工艺黄酒的品质与产量，最大程度降低生产成本，本论文主要从选育菌种、筛选稻米、优化发酵工艺三方面展开研究工作，取得较好效果。 选育黄酒糖化发酵菌种。对酵母菌YS，分别采用乙醇热冲击法、细胞紫外诱变法、原生质体紫外诱变法，结合高温驯养、TTC平板显色，最终选育到一株耐38℃高温的酵母突变株YS6.2.5。其遗传性状稳定，生长均一快速，生理耐性好，发酵力高（30℃产酒9.0％，38℃为6.5％），成品酒柔和淡爽、风味典型独特；通过正交分析，确定黄曲霉菌平板透明圈法的分离条件为：可溶性淀粉1.2％，酵母膏0.8％，上层0.5％水琼脂中碘液浓度0.7ml／100ml，下层琼脂2％，显色温度15℃。并对黄曲霉菌YA分别采用紫外线及与LiCl复合诱变、碳酸钡诱发试验及自然分离方法，结合平板透明圈法，最终选育到一株糖化力高（比YA提高103.46％）、不产黄曲霉毒素的优良黄曲霉突变株YA4.9。其遗传性状稳定，生长发酵快，菌丝密集粗短。通过单因素分析，YA4.9麸曲优化工艺为：水配比1：1，追加NaNO₃ 1.5％（种曲为（NH₄）₂SO₄ 2％），复配KH₂PO₄0.05％，MgSO₄ 0.03％，初始pH4.0-4.5，阶段式温度培养只需30～32h（种曲4～5d）即成熟。成熟麸曲糖化力最高为38.335×10³u／g曲，用于黄酒酿造，糖化彻底、出酒率高、成品酒风味好。 选用黄酒专用稻米。对7种不同的稻米品系，分析比较其理化特性、酿造特性、发酵动态及成品黄酒理化指标等，最终筛选出品种3为干黄酒优质专用稻米，品种7为米酒优质专用稻米。其中，品种3粒大饱满、白心、清香，发酵过程容易控制，出酒率高（239.05％），成品酒酒体优雅淡爽、口味协调，具有干黄酒的典型风格。品种7心白多，支／直比大（35.38），成品酒汁液多，低聚糖比例高，口感绵、甜、醇、鲜、淡爽，具有该产品的特有风格。试验表明，稻米淀粉支／直比（即淀粉质）对酿造干黄酒影响很小，对酿造米酒影响显著。淀粉支／直比在9.86～35.38范围内适合酿制现代淡爽型米酒，高于35.58适合酿制传统浓郁型米酒，低于9.86酿制的米酒苦涩味开始加重，为米酒优质原料的选用及生产工艺的改进提供科学依据。扬州大学硕士学位论文 控制合理的黄酒发酵工艺。分别就稻米原料、浸渍和蒸煮、糖化曲及酒母质量与用量、投料品温、主酵和后酵品温等，进行发酵动态分析。结合正交试验，得出干黄酒酿造的优化工艺为:浸米72h、蒸饭25一3Omin、混合数曲9%、成熟酒母7%、投料品温26士1℃、主酵前期品温30℃、后酵品温8一巧℃，既提高了黄酒的品质和产量，又能有效防止醒液酸败。试验表明，植酸作为促酵剂，对黄酒酵母菌生长发酵最适浓度为0.10%，酒精耐性由16%提高到20%，发酵96h酒精度最大可提高1 3.16%;对黄曲霉菌为0.20%，制曲36h糖化力最大可提高24.84%。植酸作为除浊剂，最适浓度为0.04%，处理24h不仅能起到除浊澄清的作用，还能增加黄酒的适口感，稳定性非常好。更多还原

【Abstract】 In this thesis, breeding S. cerevisiae and Asp. flavus strains, screening appropriative rices and optimizing process conditions were studied, in order to meet the need of production and market, to improve the quality and yield of Chinese rice wine(CRW) and to reduce its cost furthest.To breed diastatic fermentation strains. We gained one thermal-tolerant(38 C) yeast mutant (S. cerevisiae)YS6.2.5 which came from (S. cerevisiae)YS that was controlled by ethanol and heat impacting, UV radiating on its cell and protoplast, combined high temperature domesticating and TTC coloration in plate. Mutant YS6.2.5 had advantages of stable transmissibility, fast-synchronous growth velocity, better physiological tolerance, strong fermenting power(alcoholicity was 9.0% at 30 C and 6.5% at 38 C), soft taste and typical-particular flavor of finished CRW. To (Asp. flavus)YA, firstly, via multi-analysis tests, we got the optimal separatio conditions of transparent-loop in plate: 1.2% soluble starch, 0.8% yeastrel, 0.7ml iodine solution per 100ml 0.5% water-agar(top layer), 2% agar(bottom layer), color development at 15 C. Then, (Asp. flavus)YA was mutagenized by UV, UV-LiCl and BaCOa, combined natural selection and transparent-loop in plate, and we obtained one unaflatoxigenic mutant (Asp. flavus)YA4.9 which had strong diastatic power (higher 103.46% than YA). Finally, via single-analysis tests, we obtained the optimal processes of making moldy bran: 100% water, 1.5% NaNO3(mold starter was 2% (NH4)2S04)), 0.05% KH2PO4, 0.03% MgS04, initial pH4.0~4.5, culturring 30-32 hours (mold starter was 4~5 days) at phased temperature, and the diastatic power of mature moldy bran was 38.335 103u/g koji mostly, higher 34.45% than unoptimizable koji. Stable transmissibility, fast growth and fermentation velocity, dense-dumpy mycelium, high wine-ratio and excellent flavor was YA4.9 strain’ s properties.To screen appropriative rices. Comparing the characteristics of physico-chemical, brewing, fermenting and finished wine of seven different rice strains which were genetic from the same rice species, we selected strain3 as the rice-appropriative of dry CRW, and strain7 of rice wine(RW). The properties of strain3 were as follows: grain was big-full-chalky and aromatic, fermentation was controlled easily, wine-ratio was the higest(239.05%), the finished CRW style was typical. Theproperties of strain? were: grain was small-part-chalky, amylopectin/amylose ratio(a/a ratio, namely starchiness) was the highest(35.38, similar to sticky rice), the finished RW had high juice ratio and high oligosaccaride content and particular taste. It was shown that the effects of a/a ratio on dry CRW was less and on RW was more promient. Namely, the rice was suitable to brew modem-light RW when a/a ratio was 9.86-35.38, to brew traditional-rich RW when a/a ratio was higher than 35.58, and not suitable to brew RW when a/a ratio was lower than 9.86 because of the stronger bitterness. Thus, we offered RW manufacture scientific directions for selecting rice and improving technology.To control sound fermenting process. Rice type, soaking and cooking rice, the quality and dosage of moldy bran and yeast starter, initial temperature, main and post fermentation temperature were studied, and we arrived at the optimal fermenting process of dry CRW: soaking rice 72 hours, cooking rice 25~30 minutes, 9% mix moldy brans, 7% mature yeast starters, initial temperature at 26 1 C, main fermentation prophase at 30 C and post fermentation at 8~15 C, by which not only improved the quality and yield but avoided the mash acidification effectively. The effects of phytic acid(PA) on CRW were studied, it was shown that the optimal concentration of PA as stimulant on S. cerevisiae and Asp. flavus strains’ growth-and-fermentation were 0.10% and 0.20% respectively and as clearer on aggregates was 0.04%. As a result, S. cerevisiae strains’ alcoholicity increased by 13.16% at 96 hours and its alcohol tolerance strengthened from 16% to 20%, Asp. flavus strains’ diastatic power increased by 24.84% m更多还原