title: Antioxidant activities of bambara groundnut (Vigna subterranea) protein hydrolysates and their membrane ultrafiltration fractions.
abstract: In this study, the bambara protein isolate (BPI) was digested with three proteases (alcalase, trypsin and pepsin), to produce bambara protein hydrolysates (BPHs). These hydrolysates were passed through ultrafiltration membranes to obtain peptide fractions of different sizes (<1, 1-3, 3-5 and 5-10 kDa). The hydrolysates and their peptide fractions were investigated for antioxidant activities. The membrane fractions showed that peptides with sizes <3 kDa had significantly (p < 0.05) reduced surface hydrophobicity when compared with peptides >3 kDa. This is in agreement with the result obtained for the ferric reducing power, metal chelating and hydroxyl radical scavenging activities where higher molecular weight peptides exhibited better activity (p < 0.05) when compared to low molecular weight peptide fractions. However, for all the hydrolysates, the low molecular weight peptides were more effective diphenyl-1-picrylhydrazyl (DPPH) radical scavengers but not superoxide radicals when compared to the bigger peptides. In comparison with glutathione (GSH), BPHs and their membrane fractions had better (p < 0.05) reducing power and ability to chelate metal ions except for the pepsin hydrolysate and its membrane fractions that did not show any metal chelating activity. However, the 5-10 kDa pepsin hydrolysate peptide fractions had greater (88%) hydroxyl scavenging activity than GSH, alcalase and trypsin hydrolysates (82%). These findings show the potential use of BPHs and their peptide fraction as antioxidants in reducing food spoilage or management of oxidative stress-related metabolic disorders.
authors.affiliation: Department of Biotechnology and Food Technology, Faculty of Applied Sciences, Durban University of Technology, PO Box 1334, Durban 4001, South Africa. eamonsou@dut.ac.za.
authors.forename: Abimbola K
authors.initials: AK
authors.lastname: Arise
authors.forename: Adeola M
authors.initials: AM
authors.lastname: Alashi
authors.forename: Ifeanyi D
authors.initials: ID
authors.lastname: Nwachukwu
authors.forename: Oluwatosin A
authors.initials: OA
authors.lastname: Ijabadeniyi
authors.forename: Rotimi E
authors.initials: RE
authors.lastname: Aluko
authors.forename: Eric O
authors.initials: EO
authors.lastname: Amonsou
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002614:Chelating Agents / Q000378:metabolism; D016166:Free Radical Scavengers / Q000737:chemistry; D005609:Free Radicals / Q000737:chemistry; D005978:Glutathione / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D008659:Metabolic Diseases; D008970:Molecular Weight; D018384:Oxidative Stress; D010434:Pepsin A / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry*; D011492:Protein Hydrolysates / Q000737:chemistry* / Q000378:metabolism*; D012639:Seeds / Q000378:metabolism; D013381:Subtilisins / Q000378:metabolism; D013481:Superoxides; D014357:Trypsin / Q000378:metabolism; D014462:Ultrafiltration; D000070658:Vigna / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D002614:Chelating Agents; D016166:Free Radical Scavengers; D005609:Free Radicals; D010455:Peptides; D010940:Plant Proteins; D011492:Protein Hydrolysates; D013481:Superoxides; D010447:Peptide Hydrolases; D013381:Subtilisins; D014357:Trypsin; D010434:Pepsin A; D005978:Glutathione