Selective Breeding Of Function Strains And Analysis Of Component Of Shanxi Overmature Vinegar

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.