Modeling the limited degree of starch gelatinization

Abstract

The kinetics of starch gelatinization is usually described as a first‐order reaction, that is, the rate of formation of gelatinized mass is assumed to be proportional to the unreacted amount. It is also assumed that the proportional constant, the reaction rate (k), has an Arrhenius‐type dependence on temperature. The equation derived from this model predicts that all the starch eventually gelatinizes at any given temperature for any k different from zero. However, it is well known that gelatinization only initiates above the so called “gelatinization temperature.” In this study it is employed an alternative model that properly describes the actual experimental behavior, which deviates considerably from the first‐order model prediction. The model introduces an empirical parameter that quantifies the extent of gelatinization when a starch‐water mixture is held at certain temperature for “long enough.” The gelatinization degree was evaluated by applying thermal treatments to 70% moisture‐content samples for 0, 0.5, 1, 3, 5, 7, and 10 min at several temperatures (61, 63, 65, 67, and 69°C). The gelatinization activation energy (EA) derived from the alternative model is 176 ± 10 kJ/mol. Since the proposed model closely reproduces the experimental behavior, it is suggested that this value better describes the actual process. The proposed model allows for the proper modeling of the starch‐gelatinization kinetics, which is relevant in starch gelatinization studies and in food processing industry.

The Reversible and Irreversible Phenomena in Potato Starch Gelatinization

“…Another fact that shows a limitation of the kinetic approach was recently described by Pérez‐Santoz et al They pointed out that keeping starch‐water mixtures for long periods of time at temperatures below typical gelatinization temperatures does not cause a complete gelatinization, which contradicts the traditional kinetic approach [Equations and ]. This fact has however a natural explanation in the frame of the equilibrium thermodynamic approach presented here.…”

Gelatinization kinetics and starch particle structure of formula feed in limited water system employing homogeneous thermal treatments

“…A nonlinear kinetics model proposed by Perez‐Santos et al. (2016) was utilized to establish the gelatinization kinetics of formula feed as shown in Equation ():where t is the time, dα/dt is the derivative of α with respect to time, n is the reaction order, k is the rate constant holding a dependence on temperature, and α ∞ is the infinite factor, an empirical parameter that quantifies the terminal extent of gelatinization at a determined moisture content and temperature.…”

“…The transformations of starch during thermal impact of feed are highly governed by botanical source of starch, moisture content, temperature, and modification time (Altay & Gunasekaran, 2006; Kanmani et al., 2018). The starch gelatinization initiates not at any given temperatures, but above the so‐called gelatinization temperature (Perez‐Santos et al., 2016). Xing et al.…”

“…Perez‐Santos et al. (2016) introduced an empirical parameter to modify the first‐order reaction kinetics model of starch gelatinization, which quantified the extent of gelatinization for infinite time at given temperature and moisture content. Nevertheless, the evaluation of gelatinization kinetics of formula feed containing compound mixtures of ingredients has not been investigated.…”

Effects of temperature and time on gelatinization of corn starch employing gradient isothermal heating program of rapid visco analyzer

“…In essence, the degree of dependence on temperature reflected the activation energy, whose value was related to the energy barrier that had to be overcome for the transformation of corn starch (Bakshi & Singh, 1980). The starch gelatinization initiated not at any given temperatures, but above the so-called gelatinization temperature (Pérez-Santos et al, 2016).…”