【作者】 周鸣谦；

【导师】 刘冠民；

【作者基本信息】 湖南农业大学 ， 食品科学， 2002， 硕士

【摘要】 本研究针对影响南瓜汁乳酸发酵的主要因素（发酵温度、菌种配比、接种量），通过单因素试验、正交试验并对最终取得的产品进行综合感官评价，得出了能用于实际生产的最优发酵工艺条件，即：菌种配比为保加利亚乳杆菌：嗜热链球菌=1：1，接种量为4％，发酵温度为42℃，发酵时间为12h。在这一条件下发酵可以获得产酸量（以乳酸计）在0.5％以上，发酵香气与南瓜特征香气适宜的乳酸发酵南瓜汁。本文还尝试通过设计的正交旋转试验，将发酵温度、发酵时间、菌种配比、接种量对产酸量进行回归，得到以下回归方程： y=-6.5037+0.3146x₁+0.09021x₂+0.0016x₃+2.292x₄-0.0039x₁²-0.0039x₂²[y：发酵南瓜汁的产酸量，x₁：发酵温度（℃），x₂：发酵时间（h），x₃：菌种配比（乳杆菌计％），x₄：接种量（％）]。通过这一回归方程可对不同发酵条件及发酵不同阶段的产酸量进行估计或预测。 营养成分方面的研究主要是测定了还原糖、多糖、维生素C、类胡萝卜素、氨基酸总量在发酵过程中的含量的变化，为生产工艺的进一步改进提供参考。更多还原

【Abstract】 Two experiments were conducted to study fermentation process of fermented cushaw juice with lactic acid bacteria and its nutrition change during fermentation.In the first experiment, the main factors that affected the acid production rate of cushaw juice during fermentation were studied. The results are that the optimum temperature is 42 癈,the ratio of L.bulgaricus and Streptococcus is 1:1, the inoculum size is 4% and culture time is 12 hours. Under above-mentioned conditions, the acidity of cushaw juice is above 0.5% and the juice has some special aroma produced by cushaw itself and lactic acid fermentation as well. In this experiment, a regression equation has been constructed:y=-6.5037+0.3146xi+0.09021x2+0.0016x3+2.292x4-0.0039x|2-0.0039x22 In this equation y denotes acid production, X|, X2, xs and X4 denote fermentation temperature, culture time, ratio of L.h in seed culture and inoculum size, respectively. For the equation, the amount of acid production during fermentation can be predicted.In the second experiment, the changes of nutrition content in fermented cushaw juice were studied. Reducing sugar, polysaccharide, vitamin C, carotinoid and amino acid in cushaw juice were measured during fermentation and the data obtained can provide reference for improving fermentation process.更多还原