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Low pH Inactivation of Polyphenoloxidase in Apple Juice
Author(s) -
ZEMEL G. P.,
SIMS C.A.,
MARSHALL M. R.,
BALABAN M.
Publication year - 1990
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.1365-2621.1990.tb06813.x
Subject(s) - chemistry , food science , aroma , taste , organoleptic , sensory analysis
Apple polyphenoloxidase (PPO) was inactivated to 98%, 63% and 34% of the initial activity after 20 min at adjusted pH values of 2.00, 2.25 and 2.50, respectively. Higher pH values resulted in slower inactivation. In a pilot plant study, juice was acidified with HCl to pH 2.00 for 45 min and subsequently raised to the original pH with NaOH. PPO activity decreased by 88% and filtration of the juice was improved. Sensory analysis of the juice indicated that the acidified samples had a lighter but less preferred color and a disagreeable salty taste. No aroma difference was recognized.