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Heat Inactivation Kinetics of Apple Polyphenoloxidase and Activation of its Latent Form
Author(s) -
YEMENICIOĞLU AHMET,
ÖZKAN MEHMET,
CEMEROĞLU BEKIR
Publication year - 1997
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1997.tb04417.x
Subject(s) - chemistry , kinetics , food science , reaction rate constant , cultivar , horticulture , botany , biology , physics , quantum mechanics
Heat inactivation kinetics of crude polyphenoloxidase (PPO) from six apple cultivars (Golden Delicious, Starking Delicious, Granny Smith; Gloster, Starcrimson and Amasya) were studied at three temperatures (68°, 73° and 78°C). PPO activity initially increased and then decreased with heat, following a first order kinetic model. Increase in activity indicated presence of latent PPO. Regression coefficients for the linear portions of inactivation curves were computed to determine inactivation parameters. Reaction data at 78°C revealed that PPO in Amasya was the least and Starking Delicious the most heat‐stable. Rate constants for heat inactivation at 78°C ranged from 15.99–28.27. 10 −2 min −1 . Activation energies varied between 54.7–77.2 kcal. mol −1 with z values of 7.1–10.0C°.PPO in apples was generally more heat‐stable than PPO in most fruits.