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Amylolysis of maize mutant starches described with a fractal-like kinetics model

Kansou, Kamal, Buléon, Alain, Gérard, Catherine, Rolland-Sabaté, Agnès
Carbohydrate polymers 2015 v.123 pp. 266-274
Zea mays, alpha-amylase, corn starch, hydrolysis, kinetics, models, mutants, starch, swine, waxy corn
Two empirical models, a conventional first-order kinetics and a fractal-like first-order kinetic model were tested for analysing the hydrolysis of 13 wild type, single and double mutants of maize starch by porcine pancreatic α-amylase (PPA). The major difference between the two models is an additional parameter, the fractal kinetics exponent h, which enables to characterise a decrease of the reaction rate coefficient over time. The fractal-like kinetic model should be preferred to characterise the amylolysis for 10 mutants out of 13 as sugary-2 and amylose-extender curves exhibit clear reaction rate retardation, unlike normal maize and waxy maize. Analysis of the model parameter values reveals two groups of kinetics for the maize mutants: amylose-extender, normal and waxy on one hand, sugary-2 on the other hand. Possible relations between the parameters of the model and granule composition and structure are discussed.