Study On Optimum Sterilization Method Of Korean Ethnic Rice Wine

Rice wine, also known as unstrained wine which is made by microbial fermentation with rice or glutinous rice as raw materials, is one of the traditional Korean liquor. It is rich in monosaccharides, oligosaccharides, amino acids, organic acids and vitamin B group which are beneficial to human body to absorb, and small amounts of alcohol can promote blood circulation, be helpful for digestion and increase appetite. Production mode is mostly based on small family workshops, with rice or glutinous rice as raw materials and traditional koji as fermentation agent. The wine has the features of low alcohol content, high monosaccharides, disaccharides and oligosaccharides content and microorganism variety, so the improper handing during the period of preservation is easy to produce other reaction and decrease the quality of rice wine. The current sterilization method is mostly heat sterilization, and the rice wine which is refrigerated after sterilization is still easy to bad. In this paper, Korean traditional rice wine was treated by different sterilization methods and it is beneficial to optimize sterilization method, extend storage life, ensure the safety of the consumers, and meet the requirement of people to pay attention to sanitation and health.Through soaking, cooking and cooling, the rice was fermented to Korean rice wine with the addition of traditional koji and after the end of fermentation; Korean rice wine was treated by low-temperature water bath sterilization, ultraviolet sterilization, pressure sterilization and UHT methods. During storage, physical and chemical indicators, sensory indicators and microbial indicators were analyzed biweekly, and the optimal sterilization conditions of various methods were studied. The indicators of Korean rice wine after 20 weeks were analyzed, and then the more appropriate sterilization methods and conditions were initially identified. Evaluating the change of nutrient ingredients of rice wine under optimal conditions of different sterilization methods, the content of organic acids and amino acids in rice wine were explored with the combination of Amino Acids Analyzer and HPLC analysis, and then the most appropriate sterilization method was determined. The results are as follows:The physical and chemical indicators, sensory evaluation and microbial indicators of rice wine treated by different sterilization during storage were analyzed. Preliminary concluded that the optimal conditions of low-temperature heat sterilizat-ion, ultraviolet sterilization, pressure sterilization and UHT were sterilizing 5 min under 65℃; sterilizing 10 min with 15w ultraviolet light; sterilizing 10 min under 400 MPa and sterilizing 5s under 125℃, respectively.The change of quality and nutrient ingredients of Korean rice wine treated by several methods in optimum sterilization condition after 20 weeks were compared, in terms of physical and chemical indicators, microbial indicators and sensory indicators, the rice wine treated under the condition of sterilizing 5 min under 65℃ had the best quality. Comparing the total amino acids content of rice wine treated by different sterilization, it was found that the content of rice wine under low-temperature heat sterilization was higher than high-pressure sterilization, and the contents were 1.67 mg/mL and 1.18 mg/mL. The contents of organic acids were 418.43 mg/100mL and 446.71 mg/100mL. Therefore, it was concluded that the most appropriate sterilization method was sterilizing 5 min under 65℃.