Fractionation and evaluation of radical scavenging peptides from in vitro digests of buckwheat protein

Abstract

Buckwheat protein (BWP) isolate was subjected to a two-stage in vitro digestion (1 h pepsin followed by 2 h pancreatin at 37 °C). The antioxidant potential of the BWP digests was compared by assessing their capacity to scavenge 2,2′-azinobis (3-ethylbenzothiszoline-6-sulphonic acid) (ABTS +• ) and hydroxyl ( • OH) radicals. The 2-h pancreatin digest, which demonstrated the strongest activity against both radicals, was subjected to Sephadex G-25 gel filtration. Of the six fractions collected, fractions IV (456 Da) and VI (362 Da) showed the highest ABTS +• scavenging activity and were 23-27% superior to mixed BWP digest (P < 0.05). Fraction VI was most effective in neutralizing • OH and was 86 and 24% more efficient (P < 0.05) than mixed BWP digest and fraction IV, respectively. LC-MS/MS identified Trp-Pro-Leu, Val-Pro-Trp, and Val-Phe-Pro-Trp (IV), Pro-Trp (V) and tryptophan (VI) to be the prominant peptides/amino acid in these fractions.

Antioxidant Activity of Hydrolysates Prepared from Flaxseed Cake Proteins Using Pancreatin

“…•+ or DPPH • [Ma et al, 2010;Alashi et al, 2014]. Results of our study are consistent with this observation.…”

“…•+ scavenging activity of buckwheat proteins digested with the same system of enzymes was increasing in the course of hydrolysis [Ma et al, 2010]. A few studies demonstrated that fractions of peptides with the lowest MW separated from pancreatin hydrolysates were characterised by a high antiradical activity against ABTS…”

Practical problems when using ABTS assay to assess the radical-scavenging activity of peptides: Importance of controlling reaction pH and time

“…Various peptides derived from animal or plant proteins were reported to exhibit radical-scavenging activity in food and biological systems (Ma, Xiong, Zhai, Zhu, & Dziubla, 2010;Rao et al, 2012;Shen, Chahal, Majumder, You, & Wu, 2010;Xia, Bamdad, Gänzle, & Chen, 2012;Zhang, Mu, & Sun, 2014). One of the most widely used assays to screen anti-radical peptides is the ABTS assay.…”

Protective effects against H2O2-induced oxidative damage in lung fibroblast cell by peptide isolated from plasma albumin hydrolysate

“…On the other hand, some researchers illustrated that peptides containing histidine as the second N-terminal residue in the sequence possessed particularly strong antioxidant activity [33]. Some amino acids rich in bioactive peptide such as cysteine, serine, proline, lysine, leucine (isoleucine) tryptophane, valine have been reported with pretty good antioxidant capacity [16, 26, [16], LARL, LHY obtained from sardinelle by-product hydrolysate [35] and WPL, VPW and VFPW released from buckwheat protein [36] all have strong radical scavenging and antioxidant activity. Contrary to those findings, only one of the peptides (EHLREKVL) isolated from AHA in the present study contains histidine, but all of the seven peptides contain lysine.…”