Evaluation of the in vitro α-Amylase Enzyme Inhibition Potential of Commercial Dried Laver (Porphyra Species) Seaweed Protein Hydrolysate

Modulating α-amylase enzyme activity with bioactive peptides of protein hydrolysate is one of a viable strategy in the management of diabetes through the control of postprandial glucose level. In this study, four proteolytic enzymes (pepsin, neutrase, alcalase and trypsin) were used to investigate the in vitro α-amylase inhibition of dried laver seaweed (Porphyra species) protein hydrolysates. Pepsin hydrolysate showed effective inhibition rate at an IC50 value of 1.86 mg/mL protein as compared to other enzyme hydrolysate. This hydrolysate was fractionated in to three groups in molecular weight (MW) cutoff of 5 and 10 kDa (MW<5kDa, MW = 5-10kDa and MW>10kDa). The MW<5kDa showed better inhibition rate with IC50 RESEARCH PAPER Turkish Journal of Fisheries and Aquatic Sciences www.trjfas.org ISSN 1303-2712 DOI: 10.4194/1303-2712-v18_4_06 value of 1.18mg/mL. This fraction (MW<5kDa) was further separated to three fractions (F-I, F-II & F-III) using gel chromatography on Sephadex G-25. F-III achieved higher α-amylase inhibition at an IC50 value of 0.87mg/mL. The MW distribution of F-III showed the smallest MW fractions of 90-1000Da. It can be concluded that pepsin hydrolysate of seaweed protein demonstrated a high potential in inhibiting a α-amylase activity, and thus, could be used as an ingredient for development of functional foods having anti-hyperglycaemic effect.