【作者】 梁丽绒；

【导师】 赵良启；

【作者基本信息】 山西大学 ， 微生物学， 2006， 硕士

【摘要】 山西老陈醋作为我国的四大名醋之一,其历史悠久,风味独特,品质优良,享誉中外,是中华民族先祖留给我们的一块酿造艺术瑰宝。多少年来,山西老陈醋酿造一直沿用传统工艺,科技含量低,在市场竞争日益激烈的今天,渐渐暴露出诸如产品质量不稳定、产量偏低以及市场上真假老陈醋难以分辨等问题。为了满足生产及市场需求,提高山西老陈醋的品质与产量,确定山西老陈醋质量优劣的量化指标,本论文主要从筛选山西老陈醋大曲中的功能酵母菌、选育高产糖化酶菌株、优化山西老陈醋的酿酒工序并测定山西老陈醋中的有机酸成分和微量元素含量四方面展开研究。 在筛选老陈醋大曲中功能酵母菌的研究中,通过对山西老陈醋大曲中酵母菌的富集培养,筛选到9株高产乙醇或高产乙酸乙酯的酵母菌功能菌株,分别挑选高产乙醇和乙酸乙酯的酵母菌各一株进行共培养试验。通过L₁₆（4⁵）正交试验选择的最佳共培养条件为:麦芽汁培养基、pH值4.0、33℃、80 r/min摇床培养。应用该共培养物进行了酿酒试验,乙醇和乙酸乙酯产量分别达到5.93%（v/v）和0.02%（v/v）。按接种量3%将共培养物加入到传统山西老陈醋的酿酒过程中,主要生产指标较传统工艺有显著提高,其乙醇产量提高14%,糖醇转化率提高18.6%,乙酸乙酯的含量提高了1倍。结果表明,通过构建功能菌共培养体系改善大曲微生物的群落结构,提高传统酿造产品的产量与质量是一条可行的途径。 在选育高产糖化酶菌株的研究中,以工业常用菌株黑曲霉As3.4309（糖化酶活力为2200U/g）为出发菌株,采用离子注入及氯化锂—紫外线复合诱变方法多次进行交叉诱变处理,选育到一株高产糖化酶菌株LiCl Ⅳ7-31,其糖化酶活高达8272U/g,是出发菌株的3.68倍。经检测,其遗传性较稳定。与出发菌株相比较,LiCl Ⅳ7-31菌株菌丝短,孢子少,色素少,菌落颜色为黄白色,无霉味,比较适合于酿造生产。 在优化山西老陈醋的酿酒工序的研究中,将黑曲霉As3.4309及高产糖化酶LiCI Ⅳ7-31菌株分别制成麸曲,测定麸曲糖化酶活分别为3745U/g和14285.7U/g。将制备的黑曲霉As3.4309和LiCI Ⅳ7-31麸曲更多还原

【Abstract】 Shanxi overmature vinegar as one of the four famous vinegars in china, has a very long history, and is famed for its unique flavoring and excellent quality in the world. In order to increase the yield and quality of Shanxi overmature vinegar, to decrease production cost in the greatest degree and set up the quality criterion of Shanxi overmature vinegar, we had carried out the following research:Isolating yeasts from koji of Shanxi overmature vinegar: One high alcohol-producing yeast Nz19.3 and one high ethyl acetate-producing yeast Nz9.8 were were isolated from koji of Shanxi overmature vinegar under different temperatures. Then, the optimal mixed-culture conditions of Nz9.8 and Nz19.3 were studied by L16(4~5) orthogonal design. The ethanol fermentation experiment result of the mixed-culture system is that the concentration of alcohol and ethyl acetate was 5.93% and 0.02%, respectively. When the mixed-culture system was added to the traditional technology of Shanxi overmature vinegar with 3% inoculum, the yield of alcohol was increased by 14%, the conversion rate of alcohol to sugar was increased by 18.6%, and the content of ethyl acetate was increased by 100%. The result shows that the mixed-culture system of yeasts can optimize microbial community structure, and can increase the yield and quality of Shanxi overmature vinegar.Breeding of high glucoamylase-producing strain: using Aspergillus niger 3.4309 as the original strains, one high glucoamylase-producing Aspergillus niger LiCl IV7-31 was bred by the complex mutagenic method of N~+ ion implantation and ultraviolet ray-lithium chloride. The enzyme activities of glucoamylase reached 8272U/g, 3.68 times higher than enzyme activities of 3.4309. Compared to the original strain, the mycelia of Aspergillus niger LiCl IV7-31 is short, the spores is sparse, and the pigment is thin.Optimizing the alcohol brewing technology of Shanxi overmature vinegar: the high- glucoamylase bran-koji of LiCl IV7-31 and 3.4309 was made, respectively;the glucoamylase activities of the bran-koji reached 14285.7U/g and 3745U/g, respectively. When the bran-koji and mixed-culture system of yeasts were added to brewing technology of Shanxi overmature vinegar, the yield of alcohol was increased by 34%, the content of ethyl acetate was increased by 100%, and the utility of starch reached 78%. Average index were higher than the traditional brewing technology of shanxi overmature vinegar. The result indicated that Aspergillus niger LiCl IV7-31 and the mixed-culture system of yeasts is effective on increasing the yield and improving the quality of Shanxi overmature vinegar.Determination of organic acids and trace elements of shanxi overmature vinegar: the method was built that the sample preparation method of solid-phase extraction (SPE), and the determination method of organic acids by high performance liquid chromatography (HPLC) and trace elements by Flame Atomic Absorption Spectrophotometry (FASS) of shanxi overmature vinegar. Organic acids and trace elements in different Shanxi overmature vinegar were analyzed through these method, and the result showed: there are organic acids such as: acetic acid, lactic acid, malic acid, citric acid, pyruvic acid, oxalic acid, tartaric acid, formic acid in Shanxi overmature vinegar;and there are trace elements such as: K, Ca, Fe, Zn, Cu, Pb in Shanxi overmature vinegar. It was found that the content and proportion of every organic acid and trace element is distinct between different samples of Shanxi overmature vinegar. These results laid the foundations of setting up the quality criterion of Shanxi overmature vinegars.This paper provided important foundations of technique and theory for making progress in production and setting up the quality criterion of Shanxi overmature vinegars.更多还原