Abstract: 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.

Key words: tolerance, Bacillus subtilis, pulsed light, mutagenesis and screening, enzymatic activity