Separation and Characterization of A‐ and B‐Type Starch Granules in Wheat Endosperm

Abstract

Mature wheat (Triticum aestivum L.) endosperm contains two types of starch granules: large A‐type and small B‐type. Two methods, microsieving or centrifugal sedimentation through aqueous solutions of sucrose, maltose, or Percoll were used to separate A‐ and B‐type starch granules. Microsieving could not completely separate the two types of starch granules, while centrifuging through maltose and sucrose solutions gave a homogenous population for B‐type starch granules only. Centrifuging through two Percoll solutions (70 and 100%, v/v) produced purified populations of both the A‐ and B‐type starch granules. Analysis of starch granule size distribution in the purified A‐ and B‐type granule populations and in the whole‐starch granule population obtained directly from wheat endosperm confirmed that the purified A‐ and B‐type starch granule populations represented their counterparts in mature wheat endosperm. Centrifugations through two Percoll solutions were used to purify A‐ and B‐type starch granule populations from six wheat cultivars. The amylose concentrations and gelatinization properties of these populations were analyzed. All of the A‐type starch granules contained higher amylose concentrations and had higher gelatinization enthalpies than did B‐type starch granules. Although A‐ and B‐type starch granules started to gelatinize at a similar temperature, B‐type starch granules had higher gelatinization peak and completion temperatures than did A‐type starch granules

Proso millet (Panicum miliaceumL.): An Evaluation of the Microstructural Changes in the Endosperm during the Malting Process by Using Scanning-Electron and Confocal Laser Microscopy

“…Higher gelatinization enthalpies for A-type granules than for B-granules were found in wheat. The lower enthalpy value of the B-type suggests a lower proportion of organized structures or a lower stability of the crystalline regions 3,13 . Fig.…”

Comparative proteome analysis of A- and B-type starch granule-associated proteins in bread wheat (Triticum aestivum L.) and Aegilops crassa

“…A modified and improved method for starch granules extraction and the A-and B-type starch granules fractionation was established in this study based on the method described by Bancel et al [11] and Peng et al [56]. After the grains were milled, 10 g flour was weighed and soaked overnight in 100 mL of deionized water at 4°C.…”

“…In the current study, a significant effort has been focused on refining the existing methodologies in extraction and separation of starch granules and starch granule-associated proteins. As a result, an efficient and low cost method was established through modifying the method outlined by Bancel et al [11] and Peng et al [56]. For the A-and B-type granules separation, we used 70%…”

Evaluation of size distribution of starch granules in selected wheat varieties by the Low Angle Laser Light Scattering method

“…This nitrogen, however, is not only of protein origin, but comes also from phospholipids that are firmly bound to starch granules (Cornell et al 1994). Great starch granules have higher amylase concentration, they are easier degradable by activity of α-amylase, they gelatinise at lower temperatures than small starch granules (Raeker et al 1998, Peng et al 1999.…”

“…In the case of starches that were subject to alkalisation to reduce the content of crude protein, subsequently they were neutralised and resuspended into demineralised water, the method of laser light scattering gave higher values than sedimentation. Peng et al (1999) used screen analysis and sedimentation analysis for evaluation of distribution of starch granules. The results of both the methods were not comparable, particularly at screen analysis it was not possible to separate completely the both types of starch granules A and B.…”