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Kinetic modeling of native Cassava starch thermo‐oxidative degradation using Weibull and Weibull‐derived models
Author(s) -
Janković Bojan
Publication year - 2014
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.22271
Subject(s) - weibull distribution , chemistry , degradation (telecommunications) , starch , kinetic energy , oxidative phosphorylation , thermodynamics , food science , biochemistry , statistics , mathematics , physics , computer science , telecommunications , quantum mechanics
A new approach in kinetic modeling of thermo‐oxidative degradation process of starch granules extracted from the Cassava roots was developed. Based on the thermoanalytical measurements, three reaction stages were detected. Using Weibull and Weibull‐derived (inverse) models, it was found that the first two reaction stages could be described with the change of apparent activation energy (E a ) on conversion fraction (α(T)) (using “Model‐free” analysis). It was found that first reaction stage, which involves dehydration and evaporation of lower molecular mass fractions, can be described with an inverse Weibull model. This model with its distribution of E a values and derived distribution parameters includes the occurrence of three‐dimensional diffusion mechanism. The second reaction stage is very complex, and it was found to contain the system of simultaneous reactions (where depolymerization occurs), and can be described with standard Weibull model. Identified statistical model with its distribution of E a values and derived distribution parameters includes the kinetic model that gives the variable reaction order values. Based on the established models, shelf‐life studies for first two stages were carried out. Shelf‐life testing has shown that optimal dehydration time is achieved by a programmed heating at medium heating rate, whereas optimal time of degradation is achieved at highest heating rate. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 41–57, 2014.