Effects of adding milk to fermented black mulberry (Morus nigra L.) juice on its antioxidant activity in C2C12 cells and changes in volatile flavor compounds during storage

This study assessed the impact of milk on the bioactive compounds, physicochemical properties, antioxidant activity, ROS inhibition, and volatile flavor compounds of fermented black mulberry juice (FBMJ). Firstly, the results showed that 25% concentration of milk was the most suitable for preparing FBMJ-Milk. Compared to the control group, the addition of milk significantly increased the SOD activity and antioxidant capacity, as well as enhanced the total phenolic content (TPC) and SOD storage stability. Secondly, HS-SPME-GC-MS combined with OPLS-DA analysis identified 49 compounds in FBMJM, including 12 esters, 6 acids, 1 ketone, 2 aldehydes, 19 alcohols and 9 other compounds. During the storage, the levels of ethyl ester compounds decreased significantly, while the degradation of ester produced some acid and alcohol compounds. The findings revealed that the addition of milk was beneficial for maintaining the antioxidant stability of FBMJM during storage and enhancing the richness of product flavor.