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KINETICS OF HEAT/ENZYMIC DEGRADATION OF ASCORBIC ACID IN FLUTED PUMPKIN ( Telfairia occidentalis ) LEAVES
Author(s) -
ARIAHU CHARLES CHUKWUMA,
ADEKUNLE DONALD ENITAN,
NKPA NNADOZIE NKEMDIRIM
Publication year - 1997
Publication title -
journal of food processing and preservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.511
H-Index - 48
eISSN - 1745-4549
pISSN - 0145-8892
DOI - 10.1111/j.1745-4549.1997.tb00765.x
Subject(s) - ascorbic acid , chemistry , food science , arrhenius plot , kinetics , degradation (telecommunications) , activation energy , organic chemistry , telecommunications , physics , quantum mechanics , computer science
Thermal/enzymic degradations of ascorbic acid in whole, chopped and pureed fluted pumpkin leaves were studied from 60 to 100C (5–60 min). Degradation of ascorbic acid followed first order kinetics with the rate constants having maximum values at 80–90C. Ascorbic acid degradation exhibited strong deviation from linearity in thermal resistance, Arrhenius and absolute reaction rate plots at 100C indicating inactivation of the oxidative enzymes around 90C. At lower temperatures (60–90C) ascorbic acid was more stable in the whole and chopped leaves than in the pureed system. Activation energies ranged from 49 to 50.8 KJ mol −1 . At 100C, the puree matrix offered more protection to ascorbic acid.