Study On The Multi-enzymauc Iermentation Technology Of Chinese Rice Wine

It has been known that traditional soaking rice-steaming rice-fermentation brewingprocess of Chinese rice wine causes several handling difficulties, such as a large amount ofwastewater with difficult to handle, highly viscous mash and energy consumption, unevenquality of steamed rice, long period of fermentation, extremely complex of flavor caused bylarge amount of wheat Qu, etc. The liquefied production of Chinese rice wine had beeninvestigated by using enzymatic dissociation of rice starch. However, most of them onlyfocused their attention on the process optimization of liquefaction, rarely involved in thefermentation condition, fed-batch mode and the collaborative fermentation between wheat Quand enzymes. In this paper, we used ground glutinous rice between40and60meshes as rawmaterial, and focused on the influence on fermentation and taste substances by processingconditions. At the same time, the flavor substances were discussed in combination offed-batch fermentation mode, and the difference among the samples made of traditionalbrewing process, multi-enzyme brewing process and enzymes without any wheat Qu wereanalyzed. The main contents are the following:The optimal material/water ratio was set to1:1.9and addition dosage of hightemperature α-amylase was20U/g dry matter under given condition that at95±1℃and anatural pH for20min. On that basis, there were more to study the effect of different additiondosage of glucoamylase and fermentation mode on Chinese rice wine. It was shown that acombination of150U/g glucoamylase,5BU/g pullulanase and simultaneous saccharificationand fermentation (SSF) strategy appeared to be a better approach to both obtain more ethanolconcentration and to enhance fermentation completely.Then the single factor test and orthogonal experiment were conducted to confirm theoptimum conditions of fermentation. The results showed that the optimum conditions asfollows: usage of wheat Qu10%, main fermentation temperature30℃and wheat Quground20to40mesh. On the other hand, it had been observed that the fewer content of freeamino acids in the multi-enzymatic brewing rice wine were serine and cysteine, and the fewercontent organic acisd were fumaric acid and oxalic acid.In order to study the effect of fermentation characteristics and flavor substances deeply,research efforts were carried out to design experiments in combination of fed-batchfermentation.The results showed that: fed-batch fermentation whether once or twice could ledto higher ethanol production about19.8%vol and less amount of total acids compared with nofed-batch mode, and this meant lower risk of rancidity; The flavor substances were discussedin combination of fed-batch fermentation, and results showed that the amount of flavorsubstances with feeding twice was higher than once, at the same time, the stratagem that theinitial feeding amount of material were similar to the adding amount was proved to beeffective.In order to analyze the difference among samples which were produced bymulti-enzymatic process, traditional soaking rice-steamed rice-fermentation process andenzymes without wheat Qu respectively, we selected physical indicators and the content of taste and mainly flavor substances as the detection index. It was shown that: Compared withthe samples produced by enzymes without any wheat Qu, multi-enzymatic process resulted inhigher concentration of alcohol, total acids, amino nitrogen, free amino acid, organic acid,higher alcohol, ethyl benzoate, acetic ether, palmitic acid ethyl ester and acetic acid. What’smore, the samples made by multi-enzymatic process had lower contents of organic acid,higher alcohol, ethyl benzoate, acetic ether, palmitic acid ethyl ester and acetic acid thansamples made by traditional brewing process. In general, there were many advantages byusing multi-enzymatic process, such as shorter fermentation time, higher concentration ofalcohol, and more complete fermentation and higher nutritional values. At the same time, theshortage of tasteless wine could be done and the content of higher alcohol could be lower byusing multi-enzymatic process. It meant multi-enzymatic process could not only improve thefermentation rate but also made qingshuang type Chinese rice wine while reducing the usageof wheat Qu.