Effects of annealing on the polymorphic structure of starches from sweet potatoes (Ayamurasaki and Sunnyred cultivars) grown at various soil temperatures

Effect of annealing and pressure on microstructure of cornstarches with different amylose/amylopectin ratios

“…It is generally considered that A-type starch exhibits strong deflections at about 15°and 23°2h, and an unresolved doublet at 17°and 18°2 h. 38 After pressure treatment, no polymorphic transformation was observed, which corresponds with previous reports. 2,27 However, the unresolved peaks and the peak at 23°2h became weaker, whereas the peak at 15°2h remained unchanged. The decreased intensity was supported by the declined RC, which dropped about 2.9% (see Table 2) (examined by t-test; P < 0.001).…”

“…A polymorphic structure change from 'A+B' type to 'A' type during annealing has been found in sweet potato and barley starch. 2,27 Waduge et al 2 observed an increase in relative crystallinity (RC) of waxy and normal starches but an unchanged RC for the high amylose starches, using a barley family of varying amylose content (up to 50%). On the other hand, pressured gelatinization is significantly different from the traditional gelatinization, 1,28 as the pressure treatment could cause an irreversible distortion of the crystalline region in starch granules prior to a reversible hydration of the amorphous phase, which in turn leads to the destruction of the granule structure.…”

Pasting properties of a heat-moisture treated canna starch in relation to its structural characteristics

“…Transformations from B to A or B+A type by HMT have been reported for potato starch by Vermeylen et al (2006), Kawabata et al (1994), Gunaratne and Hoover (2002), and Hoover and Vasanthan (1994), and for yam starch by Gunaratne and Hoover (2002), and Hoover and Vasanthan (1994). As stated by Genkina, Wasserman, Noda, Tester, and Yuryeva (2004), HMT often results in transformation of the less thermodynamically stable B-polymorphic structure (with hexagonal packing of double helices and about 36 water molecules inside every cell) to a more stable monoclinic structure of A-type polymorphs (with about six water molecules inside the helices). In this study, the conditions used (100°C with up to 25% moisture) may not have been severe enough to alter the crystalline structure of canna starch.…”

Annealing of normal and mutant wheat starches. LM, SEM, DSC, and SAXS studies

“…The relationship between the structural and thermodynamic parameters for starches [1][2][3][4][5][6][16][17][18][19][20]23 suggests that annealing does not influence the structure of the amylose-lipid complexes.…”

“…It was proposed that the annealing diminishes defects by improvement of double helices registration and optimizes the length of double-helical chains within the crystalline lamellae. 16,17 Recent investigations on the annealing of starches with different polymorphous structures 16,18,19 have shown that small change of crystalline lamellae length causes a significant increase in melting temperature with a small 0008-6215/$ -see front matter Ó 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.carres.2004.…”