毕业论文移动版

摘要酪氨酸酶活性抑制剂能够控制黑色素生成，从而被添加到众多美白产品中，桑叶是酪 氨酸酶抑制剂植物来源之一。本文以抑制酪氨酸酶活性为目标，在单因素试验结果的基础 上，采用三因素三水平的响应曲面法就乙醇浓度、料液比和回流次数三个因素优化桑叶酪 氨酸酶抑制剂的提取工艺。结果表明，各单因素的最佳条件分别是：乙醇浓度 50%、液料 比 40 mL/g 和回流次数 3 次；以此为基础，响应曲面法得出的酪氨酸酶抑制剂桑叶粗提液 的最佳提取工艺为：乙醇浓度 50。3%、液料比 42。85 mL/g 和回流次数 3。1 次，在此条件下， 桑叶粗提液对酪氨酸酶的抑制率为 136。26%。为验证响应曲面预测桑叶黄酮提取率的可行 性，采用所得的最佳条件进行验证试验，3 次平行试验得到的桑叶粗提液对酪氨酸酶抑制 率为 135。99%，与理论预测值仅相差 0。27%。据实际情况，采用工艺乙醇浓度 50%、液料 比 43 mL/g、回流次数 3 次，此条件下桑叶粗提取液对酪氨酸酶的抑制率为 133。96%。81702

毕业论文关键词：桑叶；提取工艺；响应曲面法；酪氨酸酶活性

Abstract Tyrosinase activity inhibitor can control melanin production, so as to be added to the many whitening products, mulberry leaves are one of tyrosinase inhibitors of plant origin。 In this paper, for the optimization of Mulberry tyrosinase inhibitors extraction process which goal is to inhibit tyrosinase activity, basing on the single factor design, we used response surface methodology (RSM) and selected three factors such as the ethanol concentration, solid-liquid ratio and the number of reflux and three levels。 The results showed that the optimum conditions for each factor were ethanol concentration 50%, liquid-solid ratio 40 mL/g and a reflux 3 times。 So according to RSM, the optimum technological condition of extraction process which goal is to inhibit tyrosinase activity from mulberry leaves is ethanol concentration 50。3%, liquid-solid ratio

42。85 mL/g and a reflux 3。1 times。 Under these conditions, tyrosinase inhibition rate of the crude extracts from mulberry leaves is 136。26%。 In order to verify the feasibility of response surface prediction mulberry extraction yield, using the optimum conditions was subjected to verification experiment, the actual yield of the mulberry leaves which three parallel tests are given in is 135。99%, which is only lower than the theoretical predictive of 0。27%。 According to the actual situation, we choose the final extraction process: ethanol concentration 50%, liquid-solid ratio 43 mL/g and a reflux 3 times。 Under these conditions, tyrosinase inhibition rate of the crude extracts from mulberry leaves is 133。96%。

Keywords: Mulberry Leaves; Extraction Process; Response Surface Methodology (RSM); Tyrosinase Activity

目 录

第一章 绪论 1

1。1  前言 1

1。2  桑叶的化学成分 2

1。2。1  黄酮及黄酮苷类 4

1。2。2  多糖类 4

1。2。3  生物碱类 5

1。2。4  有机酸类 5

1。2。5  甾醇类 6

1。3  桑叶的药理作用 6

1。3。1  降血糖 6

1。3。2  抗肿瘤 6

1。3。3  降血脂、降胆固醇 7

1。3。4  改善消化系统 (责任编辑：qin)