title: Glycyl endopeptidase from papaya latex: partial purification and use for production of fish gelatin hydrolysate.
abstract: An aqueous two-phase system (ATPS) in combination with ammonium sulphate ((NH4)2SO4) precipitation was applied to fractionate glycyl endopeptidase from the papaya latex of Red Lady and Khack Dum cultivars. ATPS containing polyethylene glycol (PEG 2000 and 6000) and salts ((NH4)2SO4 and MgSO4) at different concentrations were used. Glycyl endopeptidase with high purification fold (PF) and yield was found in the salt-rich bottom phase of ATPS with 10%PEG 6000-10% (NH4)2SO4. When ATPS fraction from Red Lady cultivar was further precipitated with 40-60% saturation of (NH4)2SO4, PF of 2.1-fold with 80.23% yield was obtained. Almost all offensive odorous compounds, particularly benzyl isothiocyanate, were removed from partially purified glycyl endopeptidase (PPGE). The fish gelatin hydrolysates prepared using PPGE showed higher ABTS radical scavenging activity and less odour, compared with those of crude extract (CE). Thus antioxidative gelatin hydrolysate with negligible undesirable odour could be prepared with the aid of PPGE.
authors.affiliation: Department of Food Technology, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand.
authors.forename: Supatra
authors.initials: S
authors.lastname: Karnjanapratum
authors.affiliation: Department of Food Technology, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand. Electronic address: soottawat.b@psu.ac.th.
authors.forename: Soottawat
authors.initials: S
authors.lastname: Benjakul
mesh_terms: D000818:Animals; D000975:Antioxidants; D029441:Carica / Q000737:chemistry*; D003546:Cysteine Endopeptidases / Q000737:chemistry*; D005399:Fishes; D005638:Fruit / Q000737:chemistry*; D005780:Gelatin; D007840:Latex; D011092:Polyethylene Glycols / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D007840:Latex; D011092:Polyethylene Glycols; D005780:Gelatin; D003546:Cysteine Endopeptidases; C050874:glycyl endopeptidase
keywords: ATPS; Antioxidative activity; Gelatin hydrolysates; Glycyl endopeptidase; Odorous compounds; Papaya latex