自然发酵泡菜中乳酸菌的分离鉴定及其在金刺梨汁发酵中的应用

该研究从自然发酵泡菜中分离乳酸菌，通过形态观察、生理生化试验及分子生物学技术对其进行鉴定，然后对其生长、产酸、降解亚硝酸盐和抑菌性能进行测定，筛选性能优良的乳酸菌，并将其应用到金刺梨果汁发酵中。结果表明，分离筛选到2株产酸能力强、抑菌效果好且降解亚硝酸盐能力＞83%的优良乳酸菌，编号分别为BJ-1、BJ-31，经鉴定分别为植物乳杆菌（Lactobacillus plantarum）和短乳杆菌（Lactobacillus brevis）。与自然发酵金刺梨果汁相比，人工接种这两株菌发酵金刺梨果汁，显著缩短了发酵周期（P＜0.05），将自然发酵所需的一个月缩短为3 d，且极大地减少了金刺梨果汁发酵过程中主要营养成分的损耗，改善了金刺梨果汁的风味。发酵结束后，采用菌株BJ-1和BJ-31发酵的金刺梨果汁中维生素C（VC）含量分别为（1 571.35±49.21） mg/100 g和（1 526.41±49.36） mg/100 g，超氧化歧化酶（SOD）活力分别为（3 546.79±138.31） U/g和（3 402.42±141.71） U/g，感官评分分别为（7.20±0.75）分和（7.29±1.00）分。

Isolation and identification of lactic acid bacteria in natural fermentation Paocai and its application in the fermentation of Rosa sterilis juice

Lactic acid bacteria were isolated from natural fermentation Paocai, identified by morphological observation, physiological and biological tests and molecular biology technology. The growth, acid production, nitrite degradation and antibacterial properties were determined, and lactic acid bacteria with excellent performance were screened and applied to the fermentation of Rosa sterilis juice. The results showed that 2 excellent lactic acid bacteria with strong acid-producing ability, good bacteriostatic effect and nitrite degradation ability＞83% were isolated and screened, which were numbered BJ-1 and BJ-31, respectively, and identified as Lactobacillus plantarum and Lactobacillus brevis, respectively. Compared with the R. sterilis juice by natural fermentation, artificial inoculation of the 2 strains for R. sterilis juice fermentation, the fermentation period could be shortened significantly (P＜0.05), required time for natural fermentation was shortened from 1 month to 3 d, and the loss of main nutrients of R. sterilis juice during the fermentation was greatly reduced and the flavor of R. sterilis juice was improved. After fermentation, the vitamin C contents in R. sterilis juice fermented by strain BJ-1 and BJ-31 were (1 571.35±49.21) mg/100 g and (1 526.41±49.36) mg/100 g, the superoxide dismutase (SOD) activities were (3 546.79±138.31) U/g and (3 402.42±141.71) U/g, and the sensory scores were (7.20±0.75) and (7.29±1.00), respectively.