Development Of Mixed Liqueur Koji And Research On Production Technology Of Sweet Rice Wine

The sweet wine is made from Liqueur Koji fermentation of steamed rice, mainly sticky rice. It is widely consumed for its special feeling, sweet and mellow taste, and low alcoholic content. Although there are many kinds of sweet wine fermented by pure Rhizopus in the market, theirs flavor and feeling are worse than that of the traditional Liqueur Koji fermentation, indicating the importance of traditional Liqueur Koji. The research on the traditional Liqueur Koji needs to deeply carry out because there are much competitor in traditional Liqueur Koji and it is hardly to control. Since all the traditional Liqueur Koji need to add with polygonum hydropiper, it is meaningful to study the effect of polygonum hydropiper on traditional Liqueur Koji. The time of sweet wine is very short, and it will be bitter in a few days in summer. So the treated storage of sweet wine is a valuable subject. In this paper the sweet wine fermented by traditional Liqueur Koji and Rhizopus in market were compared by the index of sense and physical and chemical indexes. Then the Rhizopus in market which had the best comprehensive index was isolated and purified. Then the Rhizopus was cultivated in medium containing different concentration of polygonum hydropiper in order to exzamine the effect of polygonum hydropiper on the Rhizopus in aspect of growth and saccharific ability. Furthermore the traditional Liqueur Koji and pure Rhizopus were mixed to obtain the best proportion, and the fermentation conditions of mixed Rhizopus were optimized. Finally the storage conditions of sweet wine fermented by mixed Rhizopus were studied. The results are as follows:(1) Sweet wine was produced by Angela yeasts Suzhou honey liqueur Koji、Suzhou liqueur Koji and three kinds of traditional Liqueur Koji (traditional Liqueur Koji1、traditional Liqueur Koji2、traditional Liqueur Koji3), using sticky rice as the material. Then the sense and physical and chemical index were determined. The results showed that the sweet wine fermented by traditional Liqueur Koji was better in flavor and taste and the best is traditional Liqueur Koji3、and its alcohol concentration and acidity were highest. The Suzhou honey liqueur Koji was select to be the material of the following study.(2) The pure Rhizopus was cultivated in different concentration of polygonum hydropiper solution for24h. Then the amounts of Rhizopus and concentration of mycelium were tested. The result showed that polygonum hydropiper solution could improve the growth of Rhizopus. In addition, equal amounts of water-soluble starches were added into medium with different concentration of polygonum hydropiper and the yields of reducing sugar and the transformation of starch were determined by acid hydrolysis method and DNS method. The result showed that there is promoted effect of polygonum hydropiper solution on saccharify effect of Rhizopus, and80%of polygonum hydropiper solution has the best effect. (3) The Orthogonal experimental design was adopted to optimize the condition of fermentation by mixture of traditional Liqueur Koji and pure Rhizopus. The result showed that the best conditions were as follows:the optimized proportion between traditional Liqueur Koji and pure Rhizopus was7:3with the total inoculation amounts of0.30%, and the fermentation condition was32℃for48h. The sweet wine produced under this condition has the feature of traditional Liqueur Koji and pure Rhizopus at the same time.(4) Two methods of thermal force and microwave were used to treat the sweet rice wine respectively.The treatment intensity to keep fresh flavor of the product was determined, and the stability experiments of products after treatment was carried out at5℃.Microwave treatment was using the800W power Ganlanz D8023CTL-K4microwave oven.The results show that the sensory quality of fresh rice wine kept well when treated at thermal sterilization condition for70℃、21min;75℃、16min;85℃、7min and80℃、12min and microwave treatment conditions for55s. The freshness date of the products by thermal treatment at85℃for7min could last for up to40days when stored at5℃, and that of microwave treated products could last for up to50days.