Preparation, characterization and the in vitro bile salts binding capacity of celery seed protein hydrolysates via the fermentation using B. subtilis

Abstract In order to develop celery seeds-based products as cholesterol lowering-agents, the celery seed protein (CSP) was extracted by alkali-soluble acid precipitation and ultrafiltration, followed by liquid state fermentation with B. subtilis production of celery seed protein hydrolysate (CSPH) under the optimized culture conditions. The properties of CSP and CSPH were characterized by determining their in vitro binding with bile acids, molecular weight distribution, organic functional groups, free amino acid composition. Results suggested that CSPH had a molecular weight distribution around 7.8–11.5 kDa. It showed a greater bile acid binding capacity (sodium cholate > sodium deoxycholate > sodium taurocholate) than different molecular weight components of CSP. The SEM and FTIR study revealed that CSPH could form a looser tissue along with a more disordered secondary structure, which provided more active sites for the binding of CSPH to the bile salts. The hydrolysis of amide bonds by the endopeptidases of B. subtilis and the sterilization process after fermentation might be responsible for the internal structure of CSPH. Moreover, the availability of amino acids from the CSPH was greater than from its protein-fermentation substrate. The findings indicated that CSPH had potential application as a novel agent in the lipid-lowering food field.