Kinetics of degradation of ascorbic acid by cyclic voltammetry method

Cyclic voltammetry was used to examine the kinetics of degradation of ascorbic acid (AA) at different temperatures. It has been shown that the reduction of the concentration of AA in all temperatures follow the kinetics of the first order reaction. The rate constant of the oxidation reaction increas...

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Published inChemical Industry and Chemical Engineering Quarterly Vol. 21; no. 2; pp. 351 - 357
Main Authors Grudic, Veselinka, Blagojevic, Nada, Vukasinovic-Pesic, Vesna, Brasanac, Snezana
Format Journal Article
LanguageEnglish
Published Association of the Chemical Engineers of Serbia 2015
Subjects
ascorbic acid
cyclic voltammetry
green peppers
kinetics
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Summary:Cyclic voltammetry was used to examine the kinetics of degradation of ascorbic acid (AA) at different temperatures. It has been shown that the reduction of the concentration of AA in all temperatures follow the kinetics of the first order reaction. The rate constant of the oxidation reaction increases with temperature as follows: 5x10-5; 2x10-4; 1x10-3 and 3x10-3 min-1 at temperatures of 25?C, 35?C, 65?C and 90?C, respectively. The temperature dependence of the rate constant follows Arrhenius equation, and the value of activation energy of the reaction degradation is 48.2 kJ mol-1 . The effect of storage time at a temperature of 90 ?C on AA content in fresh juice of green peppers was investigated. It was shown that AA oxidation reaction in the juice is also the first order reaction, while the lower rate constant in relation to the pure AA (5x10-3 min-1) indicates the influence of other substances present in peppers. nema
ISSN:1451-9372
2217-7434
DOI:10.2298/CICEQ140712037G