摘要：以中国传统食品为来源，通过pH降低值和DPPH清除率等为指标选出产酸快、抗氧化性高的优良菌株并将其应用苹果酵素的制备。经过乳酸菌的初筛和复筛，筛选得到抗氧化性能最佳，并适合于苹果酵素发酵的菌株Y6-6，经16S rDNA鉴定为戊糖乳杆菌。通过单因素与正交实验，得到在苹果酵素发酵的最佳条件为：苹果汁的初始pH为 5。5，发酵最适温度为30℃，发酵时间为30h，乳酸菌接种量为2%，在此条件下酵素抗氧化指标的Vc当量为0。0194mg/L。 74077

毕业论文关键词：乳酸菌、酵素、DPPH、正交实验

Screening of Lactic Acid Bacteria with Antioxidant abilities and its Application in Biozyme Preparation

Abstract：This paper, we aim at screening out the suitable strains for biozyme fermentation, With the Chinese traditional food lees as the source of lactic acid bacteria。 The excellent strains with high acid fastness and high oxidation resistance were selected by pH and DPPH clearance rate and the application of apple enzyme preparation。 The strain Y6-6 was selected by screening and identified by 16S rDNA as 16 strains of Lactobacillus pentosus The optimum fermentation parameters of the apple was determined through single factor and orthogonal experiments: the initial pH of the apple juice was 5。5,the fermentation temperature was 30℃,the fermentation time was 30h, and the inoculation amount of lactic acid bacteria was 2%, Under these conditions, the concentration of the antioxidant in the enzyme was determined to be equivalent to the concentration of 0。0194 mg/L of Vc。

Keywords: Lactic acid bacteria, biozyme, DPPH, Orthogonal experiment

目录

1绪论 4

1。1、乳酸菌概述 4

1。2乳酸菌的生理功能 4

1。2。 乳酸菌抗高血压作用 4

1。2。2。乳酸菌的抗肿瘤作用 5

肿瘤发生的预防和已发生的肿瘤的抑制 5

1。2。3．乳酸菌的抗突变作用 5

1。2。4。乳酸菌的降低胆固醇作用 5

1。2。5。乳酸菌对肠道的有益作用 5

1。2。6。乳酸菌有减少龋齿的作用 6

1。2。7。乳酸菌保护胃粘膜和肝脏 6

1。3乳酸菌的抗氧化性 6

1。4酵素及其功能概述 7

1。4。1酵素的概念 7

1。4。2酵素的功能 8

1。5乳酸菌在酵素生产中的作用 9

1。6本课题研究目的及意义 10

2材料与方法 10

2。1  菌种、培养基与试剂以及配置方法 10

2。2  仪器与设备 11

2。3  实验方法 11

2。3。1乳酸菌的初筛 11

2。3。3乳酸菌的复筛 12

2。3。3乳酸菌抗氧化的鉴定 12

2。3。4  菌种的16S rDNA鉴定 13

2。3。5乳酸菌接入果汁培养并测定： 14

2。4 单因素实验 14