Metaproteomic Research Of Shaoxing Rice Wine Wheat Qu And The Qu-making Process

The theory of the metaproteomics was introduced in this paper, and all soluble proteins in the extract of rice wine wheat Qu were difined as "metoproteome". Using the two-dimensional electrophoresis (2-DE) and the mass spectrometry technology, the metaproteome of two kinds of Shaoxing rice wine wheat Qu and Qu-making process was studied. The wheat Qu that made in different region were analyzed in order to deeply understand composition and function of proteins in wheat Qu.Among63proteins of the metaproteome of Shaoxing raw wheat Qu,16proteins were secreted by14microbes. The other47proteins were mainly from wheat (Triticum aestivum) and rice(Oryza sativa) etc. According to the function, proteins of Shaoxing raw wheat Qu could be roughly divided into six categories:hydrolytic enzymes, carbohydryate metabolic enzymes, oxidoreductases, defense proeins, stroage proteins and unknown proteins. During the six stages of the Qu-making process, there were12protein spots with dramatic variations of the expression level. Among the seven protein spots which were identified successfully, five proteins were from microbes and the other two proteins were from the wheat. a-amylase, β-amylase, acid protease, neutral protease Ⅱ,β-D-glucan exohydrolase, endo-1,4-β-xylanase, feruloyl esterase were identified as the functional proteins of raw wheat Qu.All41proteins of the metaproteome of Shaoxing cooked wheat Qu were secreted by Aspergillus oryzae. They were hydrolytic enzymes, carbohydryate metabolic enzymes, other intracellular proteins and unknown proteins. There were five high abundance proteins obviously changed during the four stages of the Qu-making process. α-amylase, glucoamylase B, acid protease, neutral protease Ⅱ and alkaline protease were identified as the functional proteins of cooked wheat Qu.To analyze the metaproteome of the raw wheat Qu from Anhui, Shanghai and Shaoxing regions, the composition of non-microbial proteins (mainly from raw material wheat) was similar. But there were quite different in the composition of microbial proteins from wheat Qu made in different regions. Some microbial proteins in three kinds of wheat Qu were the same, and they were a-amylase, acid protease, feruloyl esterase and malate dehydrogenase. Most of hydrolytic enzymes in raw wheat Qu were secreted by Aspergillus oryzae, and it demonstrated that Aspergillus oryzae was the dominant and functional microbe.