【作者】 刘月梅；

【导师】 鲁周民； 白卫东；

【作者基本信息】 西北农林科技大学 ， 野生动植物保护与利用， 2008， 硕士

【摘要】 柿子的加工是柿子产业增效的一条重要途经,近年来柿子的加工呈多元化趋势,经微生物发酵酿制而成的柿果醋,营养丰富、色泽鲜亮、味道圆润,具有良好的市场前景。本研究立足于自然界自身存在的大量天然菌种和传统的柿果醋加工技术,围绕阐明柿果醋发酵规律特征和提高柿果醋醋酸发酵效率、醋酸含量及风味质量这一核心,以水柿为原料,对柿果醋发酵工艺进行了较深入系统的研究,并对不同发酵方法加工柿果醋的工艺参数进行了优化,得到以下结论:1.利用柿果浆加工的柿果醋具有柿果清香、醋香纯正、柔和可口,为柿果醋的工厂化生产提供理论和技术依据。2.采用自然发酵方法加工的柿果醋发酵周期长,残糖、残酒精含量较高,而醋酸含量较低。3.一步发酵法试验表明:柿果浆加水量以占原浆质量的30%为好,这样即可以保证一定的发酵速度,同时柿果醋醋酸含量和醋酸得率也较高。4.在传统自然发酵工艺基础上,为了缩短柿果醋发酵时间,给工厂化生产提供理论技术依据,以水柿为原料、二次正交旋转组合设计试验方案,采用响应面法对一步发酵法（发酵过程只接种酵母菌加工柿果醋）的发酵规律及工艺参数进行研究。结果表明:发酵温度对醋酸含量有极显著的影响,酵母菌接种量对醋酸含量有显著影响;建立了一步发酵法加工柿果醋工艺参数的二次多项式数学模型,验证了模型的有效性;优化出的回归方程为Y = 4.40599 - 0.166403x₁ - 0.121586x₂ -0.154911x₁² - 0.13675x₁x₂- 0.15775x₁x₃-0.148016x₃²;最佳工艺参数为发酵温度30.9℃,酵母菌接种量0.87‰,发酵周期178h,可用于指导实际生产。5.为了探索酵母菌和醋酸菌复合菌种条件下柿子原浆果醋的发酵规律,给柿果醋的生产提供理论依据。以水柿为原料,采用响应面法对柿果醋醋酸发酵过程的工艺参数进行了优化研究。结果表明,醋酸菌接种量和发酵时间对醋酸含量有极显著的影响,发酵温度对醋酸含量影响不显著;发酵温度、醋酸菌接种量、发酵时间与柿果醋醋酸含量的相关关系高度显著（p<0.01） ,均为负二次曲线型;优化出的回归方程为Y’=4.876046+0.166609x₅+0.245975x₆–0.124459x₄² -0.379195x₅²-0.282321x₆² ;最佳工艺参数为发酵温度33.1℃,醋酸菌接种量0.56‰,发酵周期110h,在此工艺条件下柿果醋醋酸含量可达4.928 g/（100 mL）;多元回归分析结果显示,发酵温度、醋酸菌接种量、发酵时间与醋酸含量之间回归模型高度显著,可用于实际生产预测。6.采用反相高效液相测定了不同发酵方法加工的柿果醋中乙酸、柠檬酸、琥珀酸、酒石酸、乳酸、草酸和苹果酸等有机酸的含量。试验表明:柿果醋中除乙酸外,主要有机酸为苹果酸、草酸、柠檬酸、琥珀酸、酒石酸、乳酸,其中苹果酸和乳酸含量较高,其次为琥珀酸和柠檬酸。有机酸的种类和含量与发酵方法、终止发酵的方式及陈酿方式等因素有关。更多还原

【Abstract】 New persimmon products development is an important way to raise the benefit. Recently the persimmon vinegar with rich nutrition, bright-colored and special flavor by microorganism fermentation has a good market vista; the base to stable and develop the market is the application of advanced techniques and the enhancement of its quality. In order to study the variation regularity of fruit vinegar production with persimmon pulp, enhance acidification ability, acetic acid content and flavor quality of persimmon vinegar, and provide theoretical foundation for persimmon processing, the systematic research works of persimmon vinegar brewing techniques, measures and technological parameters optimization of different fermentation measures have been conducted with Diospyros kaki L. as the raw material on the base of mass microorganism in nature and traditional nature fermentation technique.Conclusions have been drawn as the following:1、High quality persimmon vinegar which have good acid tastes, aroma and color characteristics of persimmon can be produced with persimmon pulp as raw material on the base of traditional nature fermentation technique. The technology provides theoretical foundation for factorization processing of persimmon vinegar.2、In order to provide theoretical foundation for persimmon vinegar processing, we studied the variation regularity of alcohol, the sugar and the acetic acid content during persimmon vinegar fermentation using natural fermentation method. The results show that remnants of alchol and sugar are high in persimmon vinegar by this fermentation style.3、In order to ensure successful accomplishment of persimmon pulp fermentation using one-step fermentation method of only inoculating activated dry yeast condition to fruit pulp, the technique of adding water to persimmon pulp and stirring persimm pulp during fermentation were applied to process persimmon vinegar. The results show that amount of water is 30% of persimmon pulp weight. We used this technique to process persimmon vinegar and obtained a better effect.4、In order to shorten fermentation time and provide theoretical foundation for persimmon processing, the technology of one-step fermentation was applied to process persimmon vinegar with Diospyros kaki L. as the raw material on the basis of traditional nature fermentation technique. Response surface methodology was applied to study variation regularity of persimmon pulp fermentation and optimize the technical parameters with the three-factor second orthogonal rotation combination experiment. The results show that fermentation temperature has a highly significant influence on acetic acid content （p<0.01） and yeast inoculation quantity has a significant influence on acetic acid content （p<0.05）. A quadratic equation has been established （Y = 4.40599 - 0.166403x₁ - 0.121586x₂ -0.154911x₁² - 0.13675x₁x₂- 0.15775x₁x₃-0.148016x₃²） between acetic acid content and the technique parameters by analyzing variation regularity in persimmon pulp fermentation. The optimum fermentation parameters are as follows: fermentation temperature 30.9℃, yeast inoculation quantity 0.87‰and fermentation time178h. Adequacy of the model equation is verified effectively and it is valuable for practical application.5、In order to study the variation regularity of fruit vinegar production with persimmon pulp by using persimmon vinegar fermentation method of inoculating yeast and acetic acid bacillus condition to fruit pulp and provide theoretical foundation for persimmon processing, response surface methodology was applied to optimize the technological parameters of acetic acid fermentation for producing persimmon vinegar with Diospyros kaki L. as the raw material. The results show that both acetic acid bacillus inoculation quantity and fermentation time have noticeably significant effects on acetic acid content （p<0.01）, but fermentation temperature has no significant effect on acetic acid content. There is a highly significant correlation between acetic acid content and fermentation temperature, acetic acid bacillus inoculation quantity and fermentation time, in a form of negative quadric curved lines relations. The optimal quadratic equation and fermentation parameters are as follows: Y’=4.876046+0.166609x₅+0.245975x₆–0.124459x₄² -0.379195x₅²-0.282321x₆²; temperature 33.1℃, inoculum of acetic acid bacillus 0.56‰and fermentation time 110h. Under these optimized conditions, the acetic acid content of persimmon vinegar is 4.928 g/（100 mL）.The results of multivariate regression analysis show that the model for regressing fermentation temperature, acetic acid bacillus inoculation quantity, fermentation time and acetic acid content is remarkable. Practical production of acetic acid content of persimmon vinegar can be forecasted by applying the model.6、The organic acids are analyzed by reverses phase HPLC. The results show that major organic acid in fermented persimmon vinegar is acetic acid. There are many other organic acids, for example malic acid, tartaric acid, oxalic acid, citric acid, lactic and succinic acid. Organic acids styles and content have correlation to fermentation method, fermentation terminate style, aging and so on.更多还原