植物乳杆菌发酵萝卜干品质变化分析

为加快发酵速率,降低产品亚硝酸盐含量,并提高产品品质,本研究以萝卜干为原料,分别接种植物乳杆菌L4(Lactobacillus plantarum L4)和植物乳杆菌B5(L.plantarum B5),并以自然发酵为对照,萝卜干发酵时间为56 d,研究L4和B5对萝卜干品质的影响。结果表明:L4、B5和自然发酵p H值降低的速率依次为:L4B5自然发酵。亚硝酸盐含量随着发酵时间的延长先增加后减小,其中L4发酵在22 d左右出现亚硝酸盐峰,峰值为(3.23±0.17)mg/kg,B5和自然发酵在33 d左右出现亚硝酸盐峰,峰值分别为(2.04±0.12)mg/kg和(3.79±0.25)mg/kg(P0.05)。挥发酯含量、游离氨基酸含量都随着发酵时间的延长呈上升趋势。L*、b*随着发酵时间的延长呈下降趋势,而a*随着发酵时间的延长呈上升趋势。发酵结束时,L4、B5和自然发酵感官评分别为88.7±2.56、81.8±1.49和74.1±3.88。由此表明,植物乳杆菌L4和B5可以缩短萝卜干的发酵周期,提高萝卜干安全性和品质,其中L4表现比B5好。

Quality Changes of Dried Radish during Fermentation by Lactobacillus plantarum

In order to accelerate the fermentation process, reduce nitrite content and improve product quality, Lactobacillus plantarum L4 and B5 were used for the fermentation of dried radish and compared with natural fermentation for their effect on the quality of fermented radish. The results indicated that the rate of pH decline during fermentation by different strains was in the decreasing order of L4 > B5 > natural fermentation. Nitrite content increased firstly and then decreased with fermentation time, and its peak value was (3.23 ± 0.17) mg/kg after about 22 days of fermentation with L4, and (2.04 ± 0.12) and (3.79 ± 0.25) mg/kg after about 33 days of B5 and natural fermentation (P < 0.05), respectively. The contents of volatile esters and free amino acid increased with fermentation time. L* and b* values decreased with fermentation time, while a* value increased. The sensory scores of L4, B5 and natural fermentation were 88.7 ± 2.56, 81.8 ± 1.49 and 74.1 ± 3.88 at the end of fermentation, respectively. These results suggest that L4 and B5 can shorten the production cycle and improve the safety and quality of fermented radish, while the performance of L4 is better than that of B5.