Preparation of a novel biofilm directed vat set (DVS) starter and its preliminary application in pickled radish

Fermentation is commonly used for preservation and processing to effectively extend the shelf life of vegetables. However, traditional pickled vegetable fermentation processes present challenges, such as bacterial interference and notable quality variations, which can be effectively addressed by the utilization of fermenting agents. This study embedded Lactiplantibacillus plantarum LR-31 with low methoxyl pectin, followed by culturing in MRS broth to prepare a biofilm directed vat set (DVS) starter. The biofilm DVS starter presented as small round calcium pectinate beads (CPB) of 2.02 ± 0.07 mm, with an effective viable bacterial count of up to 11.9 log CFU/g. After freeze-drying, the survival rate of the bacterial cells in the LR-31 biofilm CPB DVS starter reached approximately 70 %, which was significantly higher than that of the unencapsulated planktonic DVS starter. This indicated that encapsulation notably increased the freeze-dried survival rate of the microbial DVS. Furthermore, compared with the commercial fermentation DVS starter, the LR-31 biofilm CPB DVS starter effectively reduced the nitrite content in the fermentation system. Using the LR-31 biofilm CPB DVS starter for ferment radishes significantly enhanced their elasticity, cohesion, and sensory evaluation scores. This study established a theoretical foundation for using high-density biofilm DVS starters in vegetable fermentation. • The biofilm DVS starter has an effective viable bacterial count of up to 11.9 log CFU/g. • Encapsulation increased the freeze-dried survival rate of the microbial DVS by 40 %–70 %. • The biofilm CPB DVS starter effectively reduced the nitrite content in the fermentation system. • The pickle radishes fermented by biofilm CPB DVS have higher texture and sensory evaluation scores.