Effects of Structural Imperfection on Gelatinization Characteristics of Amylopectin Starches with A- and B-Type Crystallinity

Abstract

The aim of the present work was to investigate the effect of physical structures on the properties of starch granules. Starches with a high amylopectin content possessing A- and B-type crystallinity were chosen for the study. The gelatinization temperature decreased in the following order: maize (A) > potato (B) > wheat (A) > barley (A), which did not reflect a correlation with the type of crystallinity. Low values of gelatinization temperature were accompanied with high free surface energy of the crystallites. It is proposed that these data are caused by different types of imperfections in starch crystals. Annealing resulted in an enhancement of the gelatinization temperature and a decrease of the free surface energy of the crystallites for all starches reflecting a partial improvement of crystalline perfection. A limited acid hydrolysis (lintnerization) of the starches decreased the gelatinization temperature because of a partial disruption of the crystalline lamellae and an increase of the amount of defects on the edges of the crystallites. Annealing of the lintnerized starches improved the structure of maize and potato starch, giving them similar structural and physicochemical parameters, which was opposite the behavior of the annealed sample from wheat. The possible nature of removable and nonremovable defects inside the crystalline region of the starch granules is discussed. It is concluded that, besides the allomorphic A- and B-types of crystal packing, physical defects in the crystals possess a major impact on starch gelatinization.

Building block organisation of clusters in amylopectin from different structural types

“…Thus, apparently the A fp -chains remained in the cluster preparation and further down to the isolated building blocks, which contradicts our earlier suggestion that these chains are not part of the actual clusters because of their short lengths that make them unsuitable for double helix formation [7,8]. As actual part of the clusters, they might therefore introduce defects into the double helix organisation in the crystalline lamellae thereby affecting starch granule properties [39][40][41][42].…”

Fine Structure of Amylopectin

“…Blue circles symbolize A-chains, red circles external B-chains, gray circles are glucose residues involved in a branch linkage (arrows), and yellow circles are residues in internal segments of B-chains. Note that the chain segment that carries the reducing end (/) is regarded as an internal segment Bertoft et al (2008) c Kalinga et al (2013) d Hanashiro et al (2002) e Zhu et al (2011a) ECL corresponds rather well to the reported thickness of the crystalline lamellae in starch granules (Table 1.1) (Kiseleva et al 2005;Genkina et al 2007;Koroteeva et al 2007a;Kozlov et al 2007a).…”

“…The strands of the double helix are left handed and consist of six glucose residues per turn and a pitch of 2.1 nm. The length of the double helices corresponds approximately to the experimentally estimated thickness of the crystalline lamellae, i.e., 4.0-6.5 nm, depending on the type of starch (Table 1.1) (Kiseleva et al 2005;Genkina et al 2007;Koroteeva et al 2007a;Kozlov et al 2007a). …”

“…b Jenkins et al (1993) c Genkina et al (2007) d Kalinga et al (2013) e Vermeylen et al (2004) f Jenkins and Donald (1995) g Koroteeva et al (2007b) h Srichuwong et al (2005b) i Kozlov et al (2007a) defect with a lot of elongated granules (Banks and Greenwood 1973;Tester et al 2004;Kubo et al 2010;Jane et al 1994;Glaring et al 2006). The granules in waxy plants, however, are indistinguishable from those of normal amylose-containing granules (Fuwa et al 1978;Jane et al 1994;Song and Jane 2000).…”

Properties of annealed jackfruit (Artocarpus heterophyllus Lam.) seed starch

“…5 and Table 2) along with a narrowing of the endothermic peak as demonstrated by the T f -T o values (GENKINA et al, 2007). The increase in stability of the crystalline zones must have required higher temperature to melt the crystallites.…”