Comparative Analysis of the Physicochemical Properties and Bacterial Diversity of Cowpeas During Natural and Inoculated Fermentation in Different Provinces.

Fresh cowpeas have a limited shelf life at room temperature. Fermentation of cowpeas not only preserves their nutritional value but also prolongs their shelf life. This study categorized cowpea fermentation processes into natural and inoculated methods, focusing on analyzing physicochemical indices, acid production, and bacterial diversity throughout the cowpea fermentation process. We compared the moisture, protein content, and vitamin C levels of cowpeas. The acidification process was monitored using pH, total acid, and nitrite contents as indicators. Illumina MiSeq sequencing was employed to analyze the bacterial communities in fermented cowpeas at different fermentation stages. The experimental results indicated that during fermentation, pH, total acid content, and nitrite content all changed significantly. Lactobacillus exhibited high dominance in both natural fermentation and inoculated fermentation processes. Moreover, under inoculated fermentation conditions, its population size was significantly greater than that in natural fermentation. Analysis of bacterial community composition revealed that microbial diversity tended to decrease with prolonged fermentation time in both natural and inoculated fermentation systems. The results demonstrate that inoculation fermentation can shorten the fermentation cycle, lower nitrite levels, and confirm that lactic acid bacteria are the dominant microbial genus in vegetable fermentation.