柿单宁凝胶固定啤酒酵母菌发酵工艺研究
Study on fermentation process of Saccharomyces cerevisiae immobilized by persimmon tannin gel
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摘要: 目的:比较游离酵母菌、柿单宁凝胶固定的酵母菌和常用的海藻酸钠PVA复合材料固定的酵母菌对发酵速度的影响,并探究柿单宁凝胶包埋的啤酒酵母菌对麦芽汁的最佳发酵条件。方法:从青牛心柿果中提取的柿单宁与交联剂混合,包埋啤酒酵母菌,用柿单宁凝胶固定啤酒酵母菌对麦芽汁进行发酵,在单因素实验的基础之上,通过正交实验研究发酵温度、包埋量、p H和初始糖度对固定化酵母菌发酵的影响。结果:柿单宁凝胶固定的啤酒酵母菌与其他材料包埋的酵母菌相比,真实发酵度最高,达96.05%;最佳发酵条件为:包埋量10(包埋剂和酵母菌的体积比),麦芽汁初始糖度14%,p H为4.0,发酵温度30℃,此条件下,真实发酵度可达97.2%。结论:制备柿单宁凝胶条件温和,增大了包埋后酵母菌的活性,而且为这种材料的广泛使用提供了可能。Abstract: Objective:To compare the free Saccharomyces cerevisiae and immobilized Saccharomyces cerevisiae with persimmon tannin gel and immobilized Saccharomyces cerevisiae within PVA-sodium alginate and obtain a optimal set of parameters for wort fermentation with Saccharomyces cerevisiae embedded with persimmon tannin gel. Methods:Extract persimmon tannin from persimmon and mix it with crosslinking agent. Then embed Saccharomyces cerevisiae and use immobilized Saccharomyces cerevisiae with persimmon tannin gel for formentation. On the basis of single factor experiment, through the orthogonal experiment to study the effects of different parameters such as temperature, immobilized rate, p H, and initial sugar degree to the fermentation properties of immobilized Saccharomyces cerevisiae. Results:Compared with other materials the real fermentation rate of the immobilized Saccharomyces cerevisiae with persimmon tannin gel achieved 96.05%, which was the maximum value. The best fermentation conditions were as follows:immobilizing quantity 10, initial sugar degree14%, p H4 and fermentation temperature 30℃.Under the optimal conditions, the real fermentation rate achieved97.2%.Conclusion:The conditions of persimmon tannin gel preparation were mild, it increased the activity of embeded Saccharomyces cerevisiae and provided a possibility for the wide use of this materials.