title: Inhibitory effect of rice bran extracts and its phenolic compounds on polyphenol oxidase activity and browning in potato and apple puree.
abstract: Full-fatted and commercially defatted rice bran extracts (RBE and CDRBE) were evaluated for their ability to inhibit enzymatic browning in potato and apple. RBE showed more effective inhibition of polyphenol oxidase (PPO) activity and browning in potato and apple as compared to CDRBE. Five phenolic compounds in RBE and CDRBE (protocatechuic acid, vanillic acid, p-coumaric acid, ferulic acid and sinapic acid) were identified by HPLC. They were then evaluated for their important role in the inhibition using a model system which found that ferulic acid in RBE and p-coumaric acid in CDRBE were active in enzymatic browning inhibition of potato and apple. p-Coumaric acid exhibited the highest inhibitory effect on potato and apple PPO (p ⩽ 0.05). Almost all phenolic compounds showed higher inhibitory effect on potato and apple PPO than 100 ppm citric acid.
authors.affiliation: Division of Applied Food and Nutrition, Faculty of Science and Technology, Phetchaburi Rajabhat University, Phetchaburi 76000, Thailand.
authors.forename: Sukhontha
authors.initials: S
authors.lastname: Sukhonthara
authors.affiliation: Department of Food Science and Technology, Faculty of Agro-Industry, Kasetsart University, Bangkok 10900, Thailand.
authors.forename: Kunwadee
authors.initials: K
authors.lastname: Kaewka
authors.affiliation: Department of Food Science and Technology, Faculty of Agro-Industry, Kasetsart University, Bangkok 10900, Thailand. Electronic address: fagicct@ku.ac.th.
authors.forename: Chockchai
authors.initials: C
authors.lastname: Theerakulkait
mesh_terms: D004156:Catechol Oxidase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015416:Maillard Reaction; D027845:Malus / Q000378:metabolism*; D012275:Oryza / Q000737:chemistry; D010636:Phenols / Q000494:pharmacology*; D010936:Plant Extracts / Q000032:analysis / Q000494:pharmacology*; D011198:Solanum tuberosum / Q000378:metabolism*
chemical_list: D010636:Phenols; D010936:Plant Extracts; D004156:Catechol Oxidase
keywords: Apple; Browning; Polyphenol oxidase; Potato; Rice bran