title: Inactivation of polyphenol oxidase from watermelon juice by high pressure carbon dioxide treatment.
abstract: The inactivation of polyphenol oxidase from watermelon juice with high pressure carbon dioxide (HPCD) treatment was investigated. The maximum reduction of polyphenol oxidase (PPO) activity inactivated by HPCD treatment was 95.8% at 30 MPa and 50 °C for 30 min, which was far higher than 50.9% of control treatment at 50 °C for 30 min. The inactivation of PPO was adequately described by a two-fraction model, which indicated that a labile and stable fraction might present in PPO from watermelon juice. The kinetic rate constants kL and kS of labile and stable fractions were 1.976 and 0.041 min(-1) by HPCD treatment of 30 MPa and 50 °C. And the labile fraction was easier to be inactivated by kinetic analysis. HPCD treatment with the combined effects of pressure, temperature, pH reduction, and time was stronger to inactivate PPO from watermelon juice than control treatment at the same temperature.
authors.affiliation: Beijing Key Laboratory of Flavor Chemistry, Beijing Technology and Business University, Beijing, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Liu
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.
authors.forename: Xiao Song
authors.initials: XS
authors.lastname: Hu
authors.affiliation: Vegetable Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China.
authors.forename: Xiao Yan
authors.initials: XY
authors.lastname: Zhao
authors.affiliation: Vegetable Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
keywords: High pressure carbon dioxide (HPCD); Inactivation; Kinetic analysis; Polyphenol oxidase; Watermelon juice