Study On New Process For The Preparation Of Wine From Glutinous Rice

At present, most glutinous rice wine in the market is brewed through traditional process, which is loved by most consumer because of being unique taste and flavor of relating to glutinous rice and good mouthfeel, along with being rich nutrition. However, home-made workshop production process for glutinous rice wine has limited the output and productivity of the wine, including wine quality stability. The traditional process like this kind of home-made style workshop production is a big challenge to rice wine industrialized production. To improve the traditional process for glutinous rice wine, we isolate and purify the strains (Saccharomyces cerevisiae and Rhizopus spp.) from market starters and develop a kind of new process for glutinous rice wine by using defined-mixed-culture as starters, named as defined-mixed-culture-starter (DMCT) process. Based on the traditional process, the new process for glutinous rice wine was investigated and the optimum process parameters were obtained for production of the rice wine. In this thesis, the chapter 2 and chapter 3 are concerned with the optimization process parameters for brewing of the glutinous rice wine with the traditional and DMCT processes, respectively. On the basis of the results of study from the chapter 2 and chapter 3, the scale-up of traditional and DMCT processes for glutinous rice wine was studied. The research contents in details are as follows:The chapter 2 is concerned with the optimization process parameters for brewing of the glutinous rice wine with the traditional Chinese method with emphasis on using the round-grain glutinous rice (Guangxi cultivar) as raw material. The Taguchi method was employed as the experimental design method for the optimization process parameters including fermentation temperature, inoculation size, fermentation time and the ratio of rice to water. The results suggested that the optimal performance for brewing of glutinous rice wine was achieved under the conditions of the 1:0.8 ratio of rice to water, 0.5%(w/w)of inoculation level and fermentation at 30℃for 4 days.The chapter 3 is concerned with the optimization process parameters for brewing of the glutinous rice wine with the pure strains brewing with emphasis on using the round-grain glutinous rice (Guangxi cultivar) as raw material. The Taguchi method was employed as the experimental design method for the optimization process parameters including fermentation temperature, inoculation size, fermentation time and the ratio of rice to water. The results suggested that the optimal performance for brewing of glutinous rice wine was achieved under the conditions of 1:2 the ratio of rice to water, 15% of inoculation level and fermentation at 30℃for 4 days. The chapter 4 is concerned with the scale-up of traditional and DMCT processes for glutinous rice wine based on results from chapter 2-3. The production capacity of DMCT process for glutinous rice wine was greater by 1.25 times as compared to that of traditional process. The 18mL/100g or above of wine production rate via DMCT process was achieved and was higher than an average of 17.38mL/100g of that via the traditional process. The lower contents of unknown microbes, higher yeast cell number, less aroma substance and lower score of sensory evaluation were observed during the preparation of glutinous rice wine via the DMCT process, compared with the traditional process. However, like the wine by the traditional process, the glutinous rice wine produced by DMCT process still remains being unique and basic taste and flavor.