Abstract:To replace traditional pool and jar fermentation methods, a novel in-bag fermentation process for fermented mustard was studied. Small-leaf mustard greens were used as raw materials, inoculated with 1.0% compound lactic acid bacteria (LAB) (Lactiplantibacillus plantarum : Pediococcus acidilactici = 2:1), and subjected to in-bag fermentation. Blanching conditions were screened, and changes in sensory quality, physicochemical indices, and microbial profiles during fermentation were investigated. Microbial community structures were analyzed using 16S rDNA and ITS high-throughput sequencing. The results indicated that blanching in a 100°C water bath for 1 min exhibited optimal microbial control and sensory performance. During the 20-day fermentation cycle of fermented mustard, the pH decreased from 5.78 to 3.21, the total acid content increased from 0.48 g·L-1 to 6.13 g·L-1, and the nitrite content remained consistently below 1.46 mg·kg-1. The highest sensory evaluation score of 36.30 was recorded on day 15 of fermentation. The lactic acid bacteria count and total bacterial count increased to 4.33×10? CFU/mL and 4.47×10? CFU/mL, respectively, within the first 0~5 days, then decreased to 7.07×10? CFU/mL and 9.23×10? CFU/mL after 15 days, stabilizing thereafter. Yeast and mold counts increased continuously during the first 10 days, reaching a peak of 4.40×10? CFU/mL on day 10 and then remained stable. Coliform bacteria were not detected after 5 days of fermentation. The microbial composition in the in-bag fermentation system was relatively simple, with Lactiplantibacillus plantarum (83.15%) and Pediococcus acidilactici (16.10%) as the dominant bacterial species, and Meyerozyma guilliermondii (66.46%) and Hanseniaspora meyeri (30.81%) as the predominant fungal species. The study confirmed the feasibility and high safety of the in-bag fermentation process, providing new insights into addressing bottlenecks in the production of fermented vegetables.
