黄秋葵汁乳酸菌混菌发酵条件优化

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24 h内将pH值降到4.5以下，活菌数可达107 CFU/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108 CFU/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72 h。

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

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 107 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, V/V) fast reduced the pH to less than 4.5 (high
acid) and resulted in a large number of living lactic acid bacteria (108 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 (V/V) 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 .