Study On Brewing Technologies Of Low-alcohol Malus Micromalus Makino Wine

Malus Micromalus Makino is a kind of rare fruit produced in the junction area of three provinces, Shanxi, Shannxi and Inner Mongolia. In recent years, the development and utilization of Malus Micromalus Makino has gradually became a research hotspot because of its nutrition value. However at present, the most of fruits are usually wasted at the harvest peak due to the lack of storage technology and the low-level processing. In order to make full use of Malus Micromalus Makino and create a good economic benefit, use the Malus Micromalus Makino as a raw material to brew a low-alcohol wine with a alcohol content of 5%(v/v) based on its characteristic of high sugar content. Such low-alcohol fermented wine has dual nutrition value of Malus Micromalus Makino and fermented fruit wine. Moreover, it can avoid harmfull effects of high alcohol content on human body. For adjusting the dietary stucture of residents in our country and expanding consumption population, it is of great significance.The concentrated Malus micromalus Makino juice was utilized as a raw material to produce the low-alcohol Malus Micromalus Makino wine using a sugar-remaining fermentation technology. The fermentation was terminated when the alcohol content reached 5%(v/v) and the termination methods were investigated. The most suitable yeast for the low-alcohol wine was selected from 5 kinds of dry active yeasts used in the fermentation process. The factors affecting the fermentation process were analysed and the response surface methodology(RSM) was applied to optimize the fermentation process. Several kinds of clarifying agents were used to clarify the low-alcohol Malus Micromalus Makino wine, and two of them were selected to make a compound clarifying agent. In addition, the compound ratio, clarification time and clarification temperature with the compound clarifying agent were optimized by response surface methodology. Deacidification of the low-alcohol Malus Micromalus Makino wine were carried out with anion exchange resins, the optimal resin was chosed to be used to static and dynamic adsorption experiments so as to determine optimum technological conditions. Results showed that:(1) In termination experiments, the following four methods could effectively terminate the fermentation process. ①SO2 aqueous solution was added directly into the brewing must and the concentration of SO2 in must was controlled to be 360mg/L or more. ②The fermenting wine was pasteurized for 10 min at 68℃. ③The yeast in fermenting must was separated by a cool centrifugation and then cooled downed the obtained wine to reach a temperature of 4℃. ④Added SO2 aqueous solution into the obtained wine, the content of it was 60mg/L or more. Took the quality of the wine into consideration, the obtained wine after terminated fermentation by the latter two methods and post-processed had a higher sensory evaluation score. It had good sensory qualities such as reddish brown colour, transparent wine body, fruity smell and mellow taste. So the two methods were ideal termination methods.(2) VL2 was the optimal yeast for brewing the low-alcohol Malus Micromalus Makino wine because its lag phase after inoculated was shorter, the wine brewed with the yeast had a lower total acid content, volatile acid content and higher sensory evaluation score. The optimal fermentation parameters were determined to be a fermentation temperature of 21 ℃, inoculum size of 0.27 ‰, initial sugar concentration in Malus micromalus Makino juice of 20 °Brix, initial p H of 3.7. Under this optimal conditions, it had excellent sensory qualities such as reddish brown colour, transparent wine body, rich fruity aroma, coordinating bouquet and mellow taste. The sensory evaluation score of the brewed wine reached 86.17, presented a little difference of 0.15% with predicted value.(3) Bentonite and chitosan were selected from 5 kinds of clarifying agents to make a compound clarifying agent, and the clarity of wine clarified by the compound agent was superior than that by a single agent. The optimal clarification parameters were obtained by RSM to be a compound ratio of Bentonite to chitosan of 1.10g·L-1/ 0.10g·L-1, clarification time of 19.5h, clarification temperature of 18℃. Under this conditions, a clarity of wine could reach 93.63%.(4) The weakly basic anion exchange resin A451 was the optimal resin for deacidification of the Malus micromalus Makino Wine, the apparent exchange adsorption capacity of total acid with this resin was 0.131g·g-1, and it had a smaller negative effects on taste and color of wine. In static adsorption experiments, when the ratio of resin to wine was 1︰20, the highest apparent exchange adsorption capacity of total acid was 0.132g·g-1. With this ratio, A451 could reach to the equilibrium state of adsorption after 300 min and the apparent exchange adsorption capacity of total acid was 0.128 g·g-1, while the effect of temperature on the deacidification with A451 was not evident. In dynamic adsorption experiments, the deacidification with A451 was significantly affected by flow rate. Lower flow rate could obtain a higher processing volume. The optimal flow rate of A451 for low-alcohol Malus micromalus Makino Wine was of 3 BV/h. Under optimal operating conditions, after static or dynamic adsorption, could significantly increase sensory quality of wine with a lower tannin concentration.The fermentation parameters obtained in this study can provide theoretical references for production of low-alcohol Malus Micromalus Makino wine in the enterprise. So as to create a good economic benefits for enterprises and fruit growers, thus promote a vigorous development of Malus Micromalus Makino industry.