title: Composition, physicochemical properties and thermal inactivation kinetics of polyphenol oxidase and peroxidase from coconut (Cocos nucifera) water obtained from immature, mature and overly-mature coconut.
abstract: Composition, physicochemical properties and enzyme inactivation kinetics of coconut water were compared between immature (IMC), mature (MC) and overly-mature coconuts (OMC). Among the samples studied, pH, turbidity and mineral contents for OMC water was the highest, whereas water volume, titratable acidity, total soluble solids and total phenolics content for OMC water were the lowest. Maturity was found to affect sugar contents. Sucrose content was found to increase with maturity, and the reverse trend was observed for fructose and glucose. Enzyme activity assessment showed that polyphenol oxidase (PPO) in all samples was more heat resistant than peroxidase (POD). Compared to IMC and MC, PPO and POD from OMC water showed the lowest thermal resistance, with D83.3°C=243.9s (z=27.9°C), and D83.3°C=129.9s (z=19.5°C), respectively.
authors.affiliation: Food Technology Division, School of Industrial Technology, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia. thuanchew@usm.my
authors.forename: Thuan-Chew
authors.initials: TC
authors.lastname: Tan
authors.forename: Lai-Hoong
authors.initials: LH
authors.lastname: Cheng
authors.forename: Rajeev
authors.initials: R
authors.lastname: Bhat
authors.forename: Gulam
authors.initials: G
authors.lastname: Rusul
authors.forename: Azhar Mat
authors.initials: AM
authors.lastname: Easa
mesh_terms: D001628:Beverages / Q000032:analysis*; D004156:Catechol Oxidase / Q000737:chemistry* / Q000378:metabolism; D003059:Cocos / Q000737:chemistry / Q000201:enzymology* / Q000254:growth & development; D004795:Enzyme Stability; D005638:Fruit / Q000737:chemistry / Q000201:enzymology / Q000254:growth & development*; D007700:Kinetics; D009195:Peroxidase / Q000737:chemistry* / Q000378:metabolism; D010936:Plant Extracts / Q000032:analysis; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D010936:Plant Extracts; D010940:Plant Proteins; D004156:Catechol Oxidase; D009195:Peroxidase
keywords: Coconut water; Composition; Enzymatic inactivation; Maturity; Physicochemical properties