title: Production of defatted palm kernel cake protein hydrolysate as a valuable source of natural antioxidants.
abstract: The aim of this study was to produce a valuable protein hydrolysate from palm kernel cake (PKC) for the development of natural antioxidants. Extracted PKC protein was hydrolyzed using different proteases (alcalase, chymotrypsin, papain, pepsin, trypsin, flavourzyme, and bromelain). Subsequently, antioxidant activity and degree of hydrolysis (DH) of each hydrolysate were evaluated using DPPH• radical scavenging activity and O-phthaldialdehyde spectrophotometric assay, respectively. The results revealed a strong correlation between DH and radical scavenging activity of the hydrolysates, where among these, protein hydrolysates produced by papain after 38 h hydrolysis exhibited the highest DH (91 ± 0.1%) and DPPH• radical scavenging activity (73.5 ± 0.25%) compared to the other hydrolysates. In addition, fractionation of the most effective (potent) hydrolysate by reverse phase high performance liquid chromatography indicated a direct association between hydrophobicity and radical scavenging activity of the hydrolysates. Isoelectric focusing tests also revealed that protein hydrolysates with basic and neutral isoelectric point (pI) have the highest radical scavenging activity, although few fractions in the acidic range also exhibited good antioxidant potential.
authors.affiliation: Department of Food Science, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
authors.forename: Mohammad
authors.identifier: 0000-0003-1573-347X
authors.initials: M
authors.lastname: Zarei
authors.affiliation: Department of Food Science, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
authors.forename: Afshin
authors.initials: A
authors.lastname: Ebrahimpour
authors.affiliation: Department of Food Science, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
authors.forename: Azizah
authors.initials: A
authors.lastname: Abdul-Hamid
authors.affiliation: Department of Chemistry, University of Sargodha, Sargodha, 40100, Pakistan.
authors.forename: Farooq
authors.initials: F
authors.lastname: Anwar
authors.affiliation: Department of Food Science, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
authors.forename: Nazamid
authors.initials: N
authors.lastname: Saari
mesh_terms: D028023:Arecaceae / Q000737:chemistry; D001713:Biphenyl Compounds / Q000737:chemistry; D016166:Free Radical Scavengers / Q000737:chemistry* / Q000302:isolation & purification; D005609:Free Radicals / Q000737:chemistry; D006868:Hydrolysis; D000073878:Palm Oil; D010206:Papain / Q000737:chemistry; D010446:Peptide Fragments / Q000737:chemistry* / Q000302:isolation & purification; D010851:Picrates / Q000737:chemistry; D010938:Plant Oils / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification; D011492:Protein Hydrolysates / Q000737:chemistry; D059748:Proteolysis
chemical_list: D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D005609:Free Radicals; D010446:Peptide Fragments; D010851:Picrates; D010938:Plant Oils; D010940:Plant Proteins; D011492:Protein Hydrolysates; D000073878:Palm Oil; C004931:1,1-diphenyl-2-picrylhydrazyl; D010206:Papain