Characteristics and in vitro anti-inflammatory activities of protein extracts from pre-germinated black soybean [Glycine max (L.)] treated with high hydrostatic pressure

- HHP and pre-germination enhanced functionality in black soybean proteins.
- HHP and pre-germination accelerated protein degradation and peptide production.
- Conversion of black soybean proteins positively impact anti-inflammatory activities.
- HHP provided the useful information for utilization of germinated black soybean.

We investigated the influence of high hydrostatic pressure (HHP) and pre-germination on black soybean protein and peptide characteristics. Black soybean was germinated (2 or 4 d) and subjected to HHP (0.1-150 MPa; 24 h), followed by preparation of extracts and testing for anti-inflammatory activity. The highest soluble protein content (815.85 mg/g) was in soybeans subjected to HHP (100 MPa) after germination (4 d). Germination and HHP caused the degradation of high molecular weight proteins; we detected the highest content of < 3 and < 10 kDa peptides (60.46 and 88.47 mg) and free amino acids (65.70 mg) in extracts from pre-germinated soybeans that received HHP (150 MPa). Pre-germinated (4 d) soybean extracts treated with HHP (150 MPa) significantly inhibited LPS-induced expression of inflammatory markers, nitric oxide (25.01%), TNF-α (76.78%), IL-1β (58.99%), and IL-6 (84.48%) by RAW 264.7 macrophages. These results suggest that peptides derived from black soybeans subjected to HHP and pre-germination may mediate anti-inflammatory activity.