关键词: 糙米；纤维素酶；植物乳植杆菌；脂肪氧化；菌落数量

Abstract: To address the problems associated with quality deterioration of brown rice during storage, including moisture absorption, lipid oxidation and microbial contamination, this study proposed cellulase-assisted fermentation with Lactobacillus plantarum P-8 for the modification of brown rice and conducted accelerated storage tests. To evaluate the effect of cellulase-assisted fermentation on the storage quality of brown rice, changes in the moisture content, yellowness index (YI), lipid oxidation indicators (fatty acid value, conjugated diene content, and malondialdehyde content), and microbial load of brown rice subjected to cellulase-assisted fermentation (CAF-BR), enzymatically treated brown rice (E-BR), fermented brown rice (F-BR), and blank brown rice (B-BR) were compared during storage. The results showed that CAF-BR had the lowest moisture content and YI during 0–20 days, suggesting the highest resistance to moisture absorption and yellowing. Although E-BR and F-BR showed no significant difference in these parameters, both were superior to B-BR. As for the extent of lipid oxidation, the fatty acid value of CAF-BR was only (13.75 ± 0.20) mg/100 g, which was significantly lower than that of the other groups; CAF-BR and F-BR exhibited the smallest increase in fatty acid value, conjugated dienes and malondialdehyde throughout storage, while the rates of increase in E-BR and B-BR were similar and relatively high, indicating that cellulase-assisted fermentation could more effectively delay lipid oxidation. Additionally, CAF-BR had the highest total microbial count, following by F-BR, and the total microbial count and mold count increased most slowly during storage. This indicates that the cellulase-assisted fermentation might promote the proliferation of lactic acid bacteria through the release of small-molecule sugars from cellulose hydrolysis, thereby enhancing the inhibition of lipid oxidation and suppressing the growth of harmful microbes. In conclusion, cellulase-assisted fermentation with L. plantarum P-8 can effectively delay the storage stability and safety of brown rice, thereby providing theoretical and practical references for the development of green grain storage technologies.

Key words: brown rice; cellulose; Lactobacillus plantarum; fat oxidation; microbial count