植物乳杆菌在桑果浆中的发酵特性研究

A Study on Fermentation Characteristics of Lactobacillus plantarum in Mulberry Pulp

利用从桑椹中分离纯化的植物乳杆菌MLP-1发酵桑果浆,研究发酵期间桑果浆中的乳酸菌活菌数量、pH值、可滴定酸、有机酸、花色苷、总酚含量以及体外抗氧化能力的变化特征。结果表明,30℃厌氧发酵下,植物乳杆菌具有良好的底物适应性,发酵后3d活菌数量稳定在3.16×10^9CFU/mL以上并产生大量乳酸。发酵7d后,乳酸质量浓度从0.21g/L增加到15.25g/L,矢车菊素-3-葡萄糖苷质量浓度从1.33g/L减少到0.80g/L,矢车菊素-3-芸香糖苷从O.75g/L减少到0.46g/L,总花色苷质量浓度从2.28g/L降低到1.45g/L,总酚质量浓度从2.98g/L减少到2.37g/L,DPPH自由基清除能力和铁离子还原能力分别下降了24.5%和12.3%。相关性分析结果表明发酵期间抗氧化能力减弱的主要原因是花色苷及总酚含量的减少,植物乳杆菌在一定程度上影响了花色苷、总酚含量和体外抗氧化能力。

The mulberry pulp was fermented using Lactobacillus plantarum MLP-1 which had been isolated from mulberry fruit. The changes in viable counts,pH value,titratable acids,organic acids,anthocyanins,total phenol content and in vitro antioxidant capacity during fermentation were investigated. The results revealed that Lactobacillus plantarum had good substrate adaptability under anaerobic fermentation at 30 ℃. After 3 days of fermentation,the number of Lactobacillus plantarum was stable above 3. 16×10~9 CFU/m L and a large amount of lactic acid was produced. After 7 days of fermentation,the content of lactic acid increased from 0. 21 g/L to 15. 25 g/L,the content of anthocyanin-3-glucoside decreased from 1. 33 g/L to 0. 80 g/L,the content of anthocyanin-3-rutinin decreased from 0. 75 g/L to 0. 46 g/L,the total anthocyanins decreased from 2. 28 g/L to 1. 45 g/L,and the total phenolic content decreased from 2. 98 g/L to 2. 37 g/L. The DPPH radical scavenging capacity and ferric ion reducing antioxidant power were decreased by 24. 5% and12. 3%,respectively. Correlation analysis showed that the decrease of anthocyanin and total phenolics was the main reason for the decrease of antioxidant capacity during fermentation,and Lactobacillus plantarum affected the contents of anthocyanins and total phenols and their antioxidant capacity to some extent.