Effects of Modulated Differential Scanning Calorimetry (MDSC) Variables on Thermodynamic and Kinetic Characteristics During Gelatinization of Waxy Rice Starch

Abstract

The total, reversing, and nonreversing thermal properties during gelatinization of waxy rice starch (starch‐to‐water ratio = 1:2, w/w) were examined by modulated differential scanning calorimetry (MDSC). The effect of MDSC operating variables (i.e., the amplitude and frequency of temperature modulation and the underlying heating rate) on these thermal properties was determined by response surface methodology (RSM) and statistical analysis. The frequency of temperature modulation and the underlying heating rate significantly influenced the gelatinization temperatures and enthalpy changes in total and nonreversing endotherms. In addition, the combination of 0.025Hz and 4–8°C/min with a properly low degree of oscillation was suitable for characterization of starch gelatinization by MDSC. The enthalpy changes in the reversing (thermodynamic) endotherms increased, but those in the nonreversing (kinetic) endotherms decreased with increasing periods (i.e., decreasing frequencies) and underlying heating rates. However, the total enthalpy changes were only slightly influenced by the MDSC variables studied. In addition, the activation energies for the total and nonreversing events were 281.8–417.3 and 386.3–739.7 kJ/mol, respectively, depending on the MDSC conditions. From the compensation relationship between the activation energy and frequency factor, we concluded that the total and nonreversing endotherms were linked to the same single transition.

The thermal kinetics of starch gelatinization in the presence of other cake ingredients

“…This is congruent with values for related model systems; these values are in the range of 60-400 kJ mol )1 for temperatures between 50 and 100°C (Zanoni et al, 1995b). For example, Lai & Lii (1999) obtained an activation energy of 385.0 kJ mol )1 for the gelatinization of a waxy rice starch suspension (starch-to-water ratio ¼ 1:2, w/w).…”

“…The temperature for maximum gelatinization ranges between 50 and 70°C, depending upon the type of starch and its origin. The gelatinization process goes through some non-equilibrium and complex transitions, such as glass transition, hydration and swelling of the amorphous regions, the melting of crystallites within the granule, simultaneous crystallization on heating and the formation of starch-lipid complexes (Slade & Levine, 1991;Lai & Lii, 1999). Several studies have been done to help understand the molecular mechanism of the process and quantify the influence of sugar, salts, lipids and varying amounts of moisture content on the starch gelatinization phenomena (Biliaderis et al, 1980(Biliaderis et al, ,1986Horton et al, 1990;Slade & Levine, 1991).…”

A Review of Methods, Data and Applications of State Diagrams of Food Systems

“…Modulated DSC is more sensitive in the detection of glass transition temperatures than conventional DSC, due to the rapid heating rate produced by sine wave modulations [112]. Sinusoidal oscillations in heating and cooling rates produce sample temperatures that change with time in a nonlinear fashion (Modulated DSC TM Compendium, [130]).…”

Thermal properties of maize masa and tortillas with different components from maize grains, and additives

“…A launch temperature of 7°C/min was used to determine enthalpy (DH). DH refers to gelatinization phenomena, which includes complex non-equilibrium transitions, such as glass transition, hydration and swelling of the amorphous regions, the melting of crystallites within the granules and simultaneous crystallization during heating (Lai & Lii, 1999) when heated with excessive water.…”