Production of Coffee oil and Bioactive Peptides from Spent Coffee Grounds via Supercritical Carbon Dioxide Extraction and Enzymatic Hydrolysis

Supercritical carbon dioxide (SCCO2) extraction was applied for recovering non-polar compounds in spent coffee grounds (SCGs) before enzymatic hydrolysis was performed. The SCCO2 extracted oil yield of 11.93 wt% was observed at 30 MPa and 50 degrees C. The detectable volatile compounds in SCGs oil were aldehydes and flavor compounds classified as furans. Although the degree of hydrolysis of SCGs and defatted SCGs (DFSCGs) were not significantly different, the soluble protein of DFSCGs was higher than that of SCGs. Electrophoretic profiles of SCGs and DFSCGs comprise polypeptide bands at < 20 and similar to 24 kDa, which are mainly derived from 11S globulin subunits. After hydrolysis, the molecular masses of 4-20 and 24 kDa were virtually eliminated, thus releasing polypeptides with molecular masses < 4 kDa. Furthermore, the DFSCGs hydrolysate had higher total phenolic content and antioxidant capacity than that of SCGs hydrolysate. Pretreatment of SCGs with SCCO2 enhances enzymatic accessibility, improves the quality of protein hydrolysate, and procures SCGs oil as a by-product. [GRAPHICS] .