Effect of Moisture Level on the Crystallinity of Wheat Starch Aged at Different Temperatures

Abstract

Differential Scanning Calorimetry (DSC) was used to study retrogradation of wheat starch. For storage at 4°C, enthalpy (ΔH) values of retrogradation endotherm (recrystallization) of wheat starch containing various moisture levels (25–80%) slowly continued to increase except in samples with moisture level of 50, 60 and 70%. For storage at 26°C and 32°C, most recrystallization of wheat starch occured within one and two weeks of storage time, while recrystallization with a moisture level of 50% at 26°C occurred for 4 weeks. The peak temperatures of retrogradation endotherm at various moisture levels (25–80%) after 4 weeks of storage time increased largely as the storage temperatures increased from 4 to 32°C. The enthalpy values of retrogradation endotherm after 4 weeks of storage occurred to a greater extent at a lower storage temperature. The glass transition temperature and starch recrystallization have a close relationship. In the recrystallization of wheat starch, the nucleation and propagation rate after 4 weeks of storage can be converted into enthalpy and peak temperature of retrogradation endotherm.

Effect of water content on thermal behaviors of common buckwheat flour and starch

“…The peaks showed a trend shifting from higher gel-storage region to below 0°C as time increased. This was similar to the reported studies (Jang and Pyun, 1997;Ronda and Roos, 2008;Sandhu and Singh, 2007a) on retrogradation of wheat, potato and corn starches. The retrogradation onset temperatures appeared much lower than the former corresponded gelatinization temperatures.…”

“…Water content (%) Temperature (°C) Enthalpy (J/g dry matter) (Jang and Pyun, 1997;Ronda and Roos, 2008;Ferrero and Zaritzky, 2000) that glass transition, recrystallization and a shift of peak would happen with elapse of time.…”

The effect of hydroxypropylation on the structure and physicochemical properties of native, defatted and heat-moisture treated potato starches

“…Jankowski & Rha (1986) observed that retrogradation endotherm of cooked wheat grains shifted to higher temperatures, when the storage temperature was increased from 4 to 20°C. Similar findings were reported by Jang & Pyun (1997) for wheat starch gels (4Q..60%) stored at 4 and 32°C. A study with rice starch gels (50%wlw) stored at different temperatures showed that, the extent of retrogradation followed the order: refrigerated> room temperature> frozen.…”

“…Despite the numerous investigations that have been carried out to study retrogradation, the exact mechanism of retrogradation, particularfyatthe molecular level still remains unclear. The rate and extent of retrogradation is influenced by many factors such as botanical source (Orford at al., 1987;Jacobson et al, 1997), chain length of amylose and amylopectin (Gidley & Bulpin, 1989;Clark et al, 1989), water content in gel (longton & leGrys, 1981;, cooking and cooling conditions (Kimetal., 1993), storage temperature (Jankowski & Rha, 1986;Jang & Pyun, 1997) and the presence of solutes such as sugars, lipids and salts (Russell & Oliver, 1989;Katsuta et al, 1992a,b;Huang & White, 1993;Conde-Petit & Escher, 1994).…”

Pasting behaviour, textural properties and freeze–thaw stability of wheat flour–crude malva nut (Scaphium scaphigerum) gum system

“…Generally, when starch suspensions are subjected to high temperature, the granules swell and rupture due to disruption of the amylopectin double helices (hydrogen bonds dissociation), while amylose preferentially leaches out from the swollen granules (Biliaderis, 2009). Starch retrogradation or staling, caused by re-crystallization of the polymer (dispersed amylose and amylopectin) chains, in baked foods occurs when gelatinized starch is cooled down and subsequently stored at low temperature (Jang and Pyun, 1997).…”