Enhancing wheat germ stability through the isolation of antioxidant lactic acid bacteria and fermentation optimization

Wheat germ (WG), a by-product of wheat flour milling, is rich in lipid and protein. However, the lipid in WG is highly susceptible to oxidation under natural conditions, which results in a significant waste of resources. The present study was designed to resist WG lipid oxidation by isolating anti-lipid oxidation lactic acid bacteria (LAB) from traditional fat-rich Chinese fermented foods, and then the fermentation conditions of the target strain were optimized using the response surface methodology (RSM). The results showed that the target strain Lactiplantibacillus plantarum WYL8 ( L. plantarum WYL8) had high safety, controllability, antioxidant properties, and remarkably inhibiting the lipase (LPS) activity and reducing the malondialdehyde (MDA) content by fermentation, thus improving the storage stability of WG. Besides, the RSM showed that the optimal fermentation conditions were 15.6 h fermentation time, 72.2 % moisture, 5.4 % inoculum amount, 37 °C, and 8 h bacterial age ( L. plantarum WYL8 incubation time). Under the fermentation conditions, the lipid oxidation of WG was effectively inhibited, while improving its aerobic stability and nutritional value. In conclusion, L. plantarum WYL8 fermentation can effectively improve WG stability and quality, which provides a simple, efficient, low-cost, and environmentally friendly new process. • The traditional Chinese bacon sample-derived Lactiplantibacillus plantarum WYL8 can effectively inhibit lipid oxidation in fresh wheat germ. • Lactiplantibacillus plantarum WYL8 delays the deterioration of wheat germ by reducing pH, lipase activity and malondialdehyde production, and increasing total antioxidant capacity. • The optimal fermentation conditions are 72.2 % moisture, 15.6 h fermentation time, 5.4 % inoculum amount, 37 °C and 8 h bacterial age.