Analysis of the Retrogradation of Low Starch Concentration Gels Using Differential Scanning Calorimetry, Rheology, and Nuclear Magnetic Resonance Spectroscopy

Abstract

The retrogradation of 5, 10, 15, and 25% corn starch gels was measured using differential scanning calorimetry (DSC), rheology, and an array of NMR spectroscopy techniques. During the initial (<24 h) stage of retrogradation, an increase in G' corresponding to an increase in the number of solid protons participating in cross-relaxation (M(B)(0) was observed for all four concentrations studied. During the latter (>24 h) stage of retrogradation, amylopectin recrystallization becomes the dominant process as measured by an increase in deltaH(r) for the 25% starch gel, which corresponded to a further increase in. A decrease in the molecular mobility of the liquid component was observed by decreases in (17)O T(2), (1)H D(0), and T(2A). The value for T(2B) (the solid transverse relaxation time) did not change with concentration or time indicating that the mobility of the solid component does not change over time despite the conversion of the highly mobile starch fraction to the less mobile solid state during retrogradation.

Starch Retrogradation: A Comprehensive Review

“…A decrease in the molecular mobility of the liquid component was observed by decreases in 17 O T 2 (the liquid transverse relaxation rate), 1 H D 0 (the rate of H 1 diffusion coefficient), and T 2A (the liquid transverse relaxation time). The value for T 2B (the solid transverse relaxation time) did not change with concentration or time, indicating that the mobility of the solid component does not change over time despite the conversion of the highly mobile starch fraction to the less mobile solid state during retrogradation (Lewen and others ).…”

Studies of the retrogradation process for various starch gels using Raman spectroscopy

“…Amylose and amylopectin are able to reorganize helices and crystallites. 1,19 The rate of retrogradation is increased using a lower cooling temperature and a higher difference in the temperature between heating and cooling. 16 The aggregation of amylose and amylopectin chains depends on their chain length.…”

Comparison of gelatinization method, starch concentration, and plasticizer on physical properties of high‐amylose starch films

“…With the increase of starch concentration, the loose filamentous network of starch became the coarse honeycomb-like structure and this was related to the leaching of amylose and amylopectin (Lee & Rhee, 2007). Besides, the gel was becoming more solid in nature; the molecular mobility in water was decreased and the number of solid protons that participate in crossrelaxation was increased (Lewen, Paeschke, Reid, Molitor, & Schmidt, 2003). As for plasticizer, its main function was to reduce the intramolecular hydrogen bonding along polymer chains and increase the intermolecular spacing (Janjarasskul & Krochta, 2010).…”