海南酸瓜源植物乳杆菌与壳聚糖复合处理对芒果保鲜效应研究

Study on the freshness preservation effects of Lactobacillus plantarum in Hainan pickled melon and chitosan composite treatment on mango

中文关键词:  植物乳杆菌  壳聚糖  芒果  保鲜效应

英文关键词:Lactobacillus plantarum  Hainan pickled melon  chitosan  mango  preservation

中文摘要:

      目的 从海南酸瓜中筛选具有抑菌活性的植物乳杆菌, 并探究其发酵液与壳聚糖复配处理对芒果贮藏品质的影响。方法 采用MRS培养基结合生理生化特征从酸瓜中分离植物乳杆菌, 通过牛津杯法筛选对沙门氏菌、金黄色葡萄球菌、单核细胞增生李斯特氏菌具有抑菌效果的菌株, 采用16s rRNA基因序列测定方法对菌株进行确认。以芒果为保鲜对象, 分别用菌株发酵液、壳聚糖、菌株发酵液-壳聚糖复配液进行处理, 25℃贮藏12 d, 每2 d取样, 测定好果率、失重率、可溶性固形物、可滴定酸、维生素C (vitamin C, VC)、菌落总数、霉菌和酵母的变化, 评价不同处理方式对芒果的保鲜作用。结果 从海南传统发酵食品酸瓜中分离得到一株具有抑菌效果的植物乳杆菌R2。菌株发酵液、壳聚糖、菌株发酵液-壳聚糖复配液3种处理方式对芒果均具有保鲜效果, 均能有效提高芒果好果率, 降低失重率, 减缓VC的损失, 抑制表面微生物的生长而减缓芒果腐烂, 其中菌株发酵液-壳聚糖复配液的保鲜效果最佳。与CK组对比, 在贮藏第12 d时, 菌株发酵液-壳聚糖复配液处理组的好果率高40%, 失重率和可溶性固形物分别降低了4.4%和3.1%, 可滴定酸下降趋势减缓, VC的含量为CK组的1.5倍, 芒果表面菌落总数、霉菌和酵母菌落数均小于CK组。结论 海南酸瓜源植物乳杆菌发酵液结合壳聚糖复配处理能有效保持芒果的贮藏品质, 对芒果采摘后保鲜、果实品质保持和食品安全风险控制具有较好的应用价值。

英文摘要:

      Objective To screen Lactobacillus plantarum with bacteriostatic activity from Hainan pickled melon and explore the effects of composite treatment of bacterial strain fermentation solution and chitosan on mango preservation. Methods Lactobacillus plantarum strain was screened from a pickled melon by MRS medium isolation combined with physiological and biochemical characteristics, and the bacteriostatic effect against Salmonella, Staphylococcus aureus and Listeria monocytogenes were tested by oxford cup method. Then the strain with bacteriostatic activity was confirmed by 16s rRNA gene sequence. Mangoes were used as preservation object, the treatments were carried out with strain fermentation broth, chitosan and chitosan-lactobacillus complex respectively, and stored at 25℃ for 12 d. Samples were taken every 2 days to determine the changes of good fruit percentage, weight loss, soluble solids, titratable acid, vitamin C (VC), total bacterial colony, mold and yeast, and to evaluate the freshness preservation effects of different treatments on mangoes. Results A strain of Lactobacillus plantarum R2 with bacteriostatic effect was isolated from Hainan pickled melon. All 3 kinds of treatments had preservation effects on mangoes, with effectively improving the rate of good fruit, reduced the rate of weight loss, slowed down the loss of VC, and inhibited the growth of surface microorganisms to slow down the decay of mango, among which Lactobacillus plantarum and chitosan complex had the best effect. Compared with CK group, preservation effect at the twelfth days of storage, Lactobacillus plantarum and chitosan compound treatment group had 40% higher good fruit rate, 4.4% and 3.1% lower weight loss and soluble solids respectively, the decreasing tendency of titratable acid slowed down, 1.5 times more VC content than CK group, and the total number of surface microbial colonies, mold and yeast colonies were smaller than CK group. Conclusion Lactobacillus plantarum fermentation solution derived from Hainan pickled melon combined with chitosan complex treatment can effectively maintain the storage quality of mangoes, and has good application value for mango postharvest preservation, fruit quality maintenance and food safety risk control.