黄秋葵汁乳酸菌混菌发酵条件优化

Optimization of Fermentation Conditions for Okra Juice by Two Mixed Species of Lactic Acid Bacteria

为制备风味优良的乳酸发酵黄秋葵汁,研究了肠膜明串珠菌和植物乳杆菌以不同组合在发酵黄秋葵汁中的生长、产酸、感官品质以及挥发性风味成分。结果表明：植物乳杆菌单菌发酵黄秋葵汁可以在24h内将pH值降到4.5以下,活菌数可达10~7CFU/mL。肠膜明串珠菌单菌发酵黄秋葵汁无法顺利产酸。肠膜明串珠菌和植物乳杆菌以其菌液体积比2：1混合发酵黄秋葵汁,可迅速将pH值降到4.5以下,活菌数可达10~8CFU/mL,且感官品质优于植物乳杆菌单菌发酵。气相色谱-质谱联用方法分析可知,混菌发酵生成的挥发性成分比植物乳杆菌单菌发酵种类更多、含量更高。黄秋葵汁乳酸发酵最佳工艺条件为：肠膜明串珠菌和植物乳杆菌菌液以2：1比例混合、接种量5%、发酵温度35℃、发酵时间72h。

To select lactic acid bacteria stains for okra fermentation,single and mixed inoculums of two species of lactic acid bacteria（Leuconostc mesenteroides and Lactobacillus plantarum） were investigated by measuring pH,total acid,viable cell counts,volatile components and sensory evaluation of fermented okra juice.Lactobacillus plantarum when inoculated singly grew rapidly in okra juice and reached nearly 10~7 CFU/mL and pH 4.5 after 24 h fermentation,whereas Leuconostc mesenteroides alone was not useful for acid production during fermentation of okra juice.Fermentation with a mixture of Leuconostc mesenteroides and Lactobacillus plantarum（2：1,VIV） fast reduced the pH to less than 4.5（high acid） and resulted in a large number of living lactic acid bacteria（10~8 CFU/mL）.GC-MS results showed that fermented okra juice was more conducive to producing flavor compounds through mixed-culture fermentation compared with pure-culture fermentation.Sensory evaluation results also showed that mixed-culture fermentation of okra juice was more desirable than single-strain fermentation.The best inoculum for okra juice was the 2：1 mixture（VIV） Leuconostc mesenteroides and Lactobacillus plantarum.The optimal fermentation parameters were determined as 5%,35 ℃ and 72 h for inoculum amount,incubation temperature and fermentation duration,respectively.