Study On Optimization Of Wheat Qu-making Process Of Chinese Rice Wine Wheat Qu

Wheat Qu-making with wheat, brewing with wheat Qu is a traditional operatingprocess of Chinese rice wine fermentation. Wheat Qu, as saccharifying, leaven andaroma-producing agents in Chinese rice wine brewing, has a great impact on the quality ofliquor and alcohol yield. In this paper, Aspergillus oryzae Su-16, the strain used for makingcooked wheat Qu in the factory, was studied as well as one strain with strong enzymes activityof cellulase and xylanase, which was screened from121fungi isolating from wheat Qu. Withthe object of increasing the utilization of raw materials, both strains were used to optimize theprocess of wheat Qu-making. Main results were as follows:Eeight strains with enzyme activity of cellulase and five strains with enzyme activity ofxylanase were obtained from121fungi by the Congo red plate method. Combined withmaking cooked wheat Qu by them, strain CF7was selected by its higher enzymes activitythan the other seven strains. The enzymes activity of α-amylase, glucoamylase, protease,cellulase and xylanase in corresponding cooked wheat Qu were compared to each other. Thestrain CF7was identified as Aspergillus niger by its morphology and molecular identification.The optimum mixing ratio of A.niger CF7to A.oryzae was8:2to make cooked wheat Qu.The effects of Qu-making temperature, Qu-making time, liquid ratio and inoculum on theprocess of the wheat Qu-making with A.niger CF7and A.oryzae Su-16has been studied. Andenzymes activity of cellulase and xylanase were measured in all experiments. Moreover,designed experiments by using of CCD, and coupled neural networks with genetic algorithmsto optimize the process of mixed stains wheat Qu-making by cellulase and xylanase activitiesmeasured. The results showed that the optimal conditions were: Qu-making temperature of31.0℃, Qu-making time of52.0h, liquid ratio of1:0.63, inoculum of7.8%. Under theseconditions, the enzymes activity of cellulase and xylanase in mixed wheat Qu were up to32.5U/g and56.4U/g,7.9times and10.9times higher than that of wheat Qu-making withA.oryzae Su-16alone, respectively.Two groups of small-scale rice wine fermentation experiment were performed. Thealcohol yields of each group were increased by6.1%and6.9%in the same time compared tothe control, respectively. The volatile flavor compounds and free amino acid were measuredafter fermentation by GC-MS and HPLC, respectively. There was little difference of contentof alcohols, esters, aldehydes and acids flavor compounds between the experimental groupand the control group. However, the concentration of flavor compounds in the experimentalgroup was higher than that of the control group, as well as, the concentration of amino acid.The sensory evaluation on Chinese rice wine was measured in the aspects of color, smell,taste and wine style”，physically and chemically accorded with GB/T13662-2008．...