山楂山药酸奶储藏过程中的品质分析 以山药、山楂、鲜牛奶为主要原料，对山楂山药酸奶进行研制。以感官评分、色差和质构特性为评价指标，通过单因素试验分别确定山药浆、山楂浆、白砂糖以及乳酸菌发酵剂添加量的最优参数。基于单因素实验结果，采用正交试验优化山楂山药酸奶的工艺配方并进行相关性分析。然后对最优配方的山楂山药酸奶在4℃冷藏条件下储藏14 d，每2 d进行乳酸菌活菌数、持水性、pH、酸度的测定。结果表明，山楂山药酸奶最优配方：鲜牛奶质量100 g为基准，山药浆14 %、白砂糖8 %、山楂浆6 %、乳酸菌发酵剂5 %。在相关性分析下，酸奶各指标间有复杂的关系。此配方下品质分析得知，随冷藏时间的延长乳酸菌活菌数增加，持水性减低、pH减小、酸度增大。其中在第12 d以后该酸奶品质下降幅度很大。结果提示该工艺配方下的山楂山药酸奶，在4 ℃冷藏条件下储藏不宜超过12 d。 关键词：山楂；山药；酸奶；储藏；品质分析 Abstract Taking yam, hawthorn and fresh milk as main raw materials, the hawthorn yam yoghurt was developed. Taking sensory score, color difference and texture characteristics as evaluation indexes, the optimal paraneters of yam pulp, hawthorn pulp, white sugar and lactic acid bacteria starter were determined by single factor experiment. Based on the results of single factor experiment, orthogonal test was used to optimize the technological formula of hawthorn and yam yoghurt, and the correlation analysis was carried out. Then, the optimal formula of hawthorn and yam yoghurt was stored at 4 ℃ for 14 days, and the viable count, water holding capacity, pH and acidity of lactic acid bacteriawere measured every 2 days. The results showed that the optimal formula of hawthorn and yam yoghurt was as follows: 100 g of fresh milk,14 % of yam pulp, 8 % of white sugar,6 % of hawthorn pulp and 5 % of lactic acid bacteria starter. Under the correlation analysis, there are complex relationships among the indexes of yogurt. According to the quality analysis of this formula, with the extension of cold storage time, the number of viable lactic acid bacteria increased, the water holding capacity decreased, the pH decreased and the acidity increased. Among them,the quality of yoghurt declined greatly after the 12th day. The results suggested that the hawthorn and yam yoghurt with this technological formula should not be stored for more than 12 days at 4 ℃. Key words:Hawthorn;Yam;Yogurt;Storage;Quality analysis 目 录 1前 言 1 1.1 山药简介 1 1.2 山楂简介 1 1.3 酸奶简介 1 1.4 研究目标和意义 2 1.5 研究内容 2 1.5.1 山楂山药酸奶的工艺优化 2 1.5.2 山楂山药酸奶的品质研究 2 1.5.3 山楂山药酸奶储藏过程中的品质分析 2 2试验材料与方法 3 2.1 材料和试剂 3 2.2 仪器与设备 3 2.3 工艺流程 3 2.4 操作要点 3 2.4.1山药浆的制备 3 2.4.2山楂浆的制备 3 2.4.3搅拌 4 2.4.4均质 4 2.4.5杀菌 4 2.4.6冷却 4 2.4.7发酵 4 2.4.8冷却后熟 4 2.5 单因素试验 4 2.6 正交试验 4 2.7 各项指标测定 4 2.7.1感官评分 4 2.7.2质构特性检测 5 2.7.3色差测定 5 2.7.4乳酸菌活菌数、持水性、pH和酸度的测定 5 3结果与分析 6 3.1 单因素试验结果 6 3.1.1 山药浆添加量对山楂山药酸奶品质的影响 6 3.1.2 白砂糖添加量对山楂山药酸奶品质的影响 6 3.1.3 山楂浆添加量对山楂山药酸奶品质的影响 7 3.1.4 乳酸菌发酵剂添加量对山楂山药酸奶品质的影响 8 3.2 正交试验结果分析 8 3.3相关性分析 10 3.4验证试验 10 3.5酸奶储藏期间乳酸菌活数的变化 11 3.6酸奶储藏期间持水性的变化 11 3.7酸奶储藏期间pH的变化 12 3.8酸奶储藏期间酸度的变化 13 4结 论 13 参考文献 15
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