Enzyme proteolysis enhanced extraction of ACE inhibitory and antioxidant compounds (peptides and polyphenols) from Porphyra columbina residual cake

摘要

The traditional method to obtain phycocolloids from seaweeds implies successive extraction steps with cold and hot water. The residual cake derived from phycocolloids obtaining process of red seaweed Porphyra columbina is a waste containing 27 % protein and 10.7-mg gallic acid equivalents (100 g)(-1). Seaweeds contain functional proteins, and the enzymatic hydrolysis of these proteins has been shown to release bioactive peptides. The aims of this study were to extract bioactive peptides and polyphenols after enzymatic hydrolysis of the residual cake and to evaluate their ACE inhibitory and antioxidant capacities (TEAC, DPPH, and copper-chelating activity). Residual cake hydrolysate has low molecular weight peptides containing Asp, Glu, Ala, and Leu. Residual cake hydrolysate had higher protein solubility than residual cake. ACE inhibition (a parts per thousand 45 %) and radical scavenging activity (TEAC and DPPH inhibition) were attributed mainly to low molecular weight peptides (500 Da) and polyphenols compounds released during proteolysis. The 50 % inhibition protein concentration value (IC50) corresponded to residual cake hydrolysate was 1.01 +/- 0.02 and 0.91 +/- 0.01 g L-1, for ABTS and DPPH, respectively. Also, residual cake hydrolysate had high copper-chelating activity (a parts per thousand 97.5 %). Hydrolysis could be used as a means to obtain ACE inhibitory and antioxidant compounds (peptides and polyphenols) from algae protein waste and add value to the phycocolloids extraction process.