UV-B Protective and Antioxidant Activities of Protein Hydrolysate From Sea Cucumber (Holothuria scabra) Using Enzymatic Hydrolysis
Chitpon Doungapai, Thanyaporn Siriwoharn, Yuwares Malila, Narongchai Autsavapromporn, Sakunkhun Makkhun, Suthasinee Yarnpakdee, Kittisak Jantanasakulwong, Joe M. Regenstein, Sutee Wangtueai
Abstract
Sea cucumber is rich in protein that can be used to prepare a potential derived bioactive peptide for antioxidant and protective effect against UV-B induced skin cell damage. This study aimed to optimize preparation of sea cucumber hydrolysate with both UV-B protective and antioxidant activities using three commercial enzymes using response surface methodology (RSM) with a face-centered central composite design (face- centered CCD). Hydrolysis time and concentration of enzyme effects on the degree of hydrolysis (DH), yield, antioxidant and UV-B protective activities of sea cucumber hydrolysates were determined. The optimum conditions for sea cucumber hydrolysis using papain (SCP), alcalase (SCA), or flavourzyme (SCF) were 3.6, 5.0, and 4.1% (w/w protein), respectively, and a hydrolysis time of 360 min. The resulting hydrolysates had a DH of 81-91%, yield of 13-14%, IC 50 for DPPH radical scavenging activity of 0.3-4.1 mg/mL, FRAP of 0.5-0.6 mmol FeSO 4 /mL, and IC 50 for ABTS radical scavenging activity of 1.3-1.6 mg/mL. The UV-B protective activity was reported as the HaCaT cell viability percentage after UV-B treatment. The SCP, SCA, and SCF hydrolysates showed 72.4, 74.5, and 71.3% cell viability, respectively. The concentration of hydrolysates with 80% survival of HaCaT cells was 0.21, 0.15 and 0.20 mg/mL for SCP, SCA and SCF, respectively. Thus, the SCP was selected for bioactive peptide isolation and characterization. The SCP contained hydrophilic and hydrophobic amino acids of 42.4 and 57.6%, respectively. The ultrafiltration and Sephadex G-25 gel filtration chromatography were done for peptide isolation from the SCP. Six potential peptides were identified using LC-MS/MS as Leu-Val-Asn-Glu-Leu-Thr-Glu-Phe-Ala-Gln (1163 Da), Leu-Val-Asn-Glu-Val-Thr-Glu-Phe-Ala-Gln (1149 Da), Phe-Val-Asp-Ser-Ser-Ala-Thr-Thr (826 Da), Phe-Asn-Asp-Leu-Gly-Ala-Trp (821 Da), Phe-Pro-Asp-Thr-Thr-Thr-Leu (793 Da), and Lys-Phe-Gly-Glu-Gly-Lys (664).