抗氧化活性乳酸菌的分离鉴定及其在泡菜发酵中的应用

本研究从农家自制泡椒中分离并鉴定出三株具有抗氧化活性的乳酸菌。并用这几株乳酸菌组合后发酵泡菜,同时设立自然发酵组作对照,分别测定了乳酸菌菌株和1~5 d发酵泡菜的抗氧化活性,以揭示人工接种抗氧化活性乳酸菌在泡菜发酵中的作用。结果发现添加乳酸菌的泡菜发酵周期比自然发酵泡菜缩短2 d。泡菜发酵实验表明添加乳酸菌发酵泡菜的抗氧化活性远大于自然发酵泡菜的抗氧化活性。到发酵后期,三个发酵组中除DPPH自由基清除率无显著差异外(p0.05),自然发酵组的还原力、羟基自由基和ABTs自由基清除率显著低于人工接种组,其中羟基自由基清除率的差异最为显著,均大于自然组清除率28.41%的两倍以上。通过感官品尝实验对泡菜的风味进行初步评估,表明添加乳酸菌发酵泡菜的风味较自然发酵更佳。进一步通过GC-MS对泡菜中的香气成分进行初步分析,结果证明接种乳酸菌发酵泡菜的风味成分中烷烃和酯类比自然发酵泡菜中更为丰富,二者的总比例在所测峰面积比例中均高出自然组27%~30%。本研究为泡菜的健康发酵和泡菜风味的优化提供了理论依据。

Isolation and Identification of Antioxidant Lactic Acid Bacteria and its Application in Pickle Fermentation

Three strains of lactic acid bacteria with antioxidant activity were isolated and identified from homemade chili pickle. These strains were used in pickle fermentation and compared with natural fermentation. The antioxidant activities of the bacterial strains and vegetables pickled for 1~5 d were determined in order to reveal the effect of vegetable pickling using artificial inoculation of lactic acid bacteria. Results showed that the optimum pickling period of vegetables with added lactic acid bacteria was two days shorter than that of naturally fermented vegetables. The antioxidant activity of vegetables pickled by the addition of lactic acid bacteria was far greater than that of vegetables pickled naturally. At late stages of fermentation, there was no significant difference in DPPH free radical scavenging between the three fermentation groups (p<0.05). The reducing power, hydroxyl radical, and ABTs free radical scavenging rates of the naturally fermented group was significantly lower than that of the artificially inoculated group. Among these, the difference in the scavenging rate of hydroxyl free radicals was the most significant at 28.41%, a greater than twofold increase compared to the naturally fermented group. Preliminary sensory evaluation experiments of the taste of the pickled vegetables showed that those pickled with added lactic acid bacteria had a better taste and flavor compared to the naturally fermented pickled vegetables. Furthermore, preliminary GC-MS analysis of aromatic components of the pickled vegetables was conducted. Results confirmed that the alkane and ester flavor components of vegetables pickled with lactic acid bacteria were more abundant than those of naturally pickled vegetables. Comparing the total peak area ratio measured between the two components showed an increase of 27~30% over the naturally pickled group. This study provides a theoretical basis for the healthy pickling of foods and improvement of their flavor.