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Surface structure and water adsorption behavior of waxy/amylose extender (wx/ae) double‐mutant rice starch

Author:
Takagi, Hiroki, Suzuki, Shiho, Akdogan, Guray, Kitamura, Shinichi
Source:
Die Stärke = 2017 v.69 no.11-12
ISSN:
0038-9056
Subject:
adsorption, amylose, bound water, crystal structure, diameter, differential scanning calorimetry, nanomaterials, nitrogen, porosity, relative humidity, rice starch, scanning electron microscopy, surface area
Abstract:
We studied the surface structure and water adsorption behavior of waxy/amylose extender (wx/ae) double‐mutant rice starch using scanning electron microscopy, nitrogen gas adsorption, and water adsorption capacity analysis under various relative humidity conditions, and the nature of the bound water in the starch by differential scanning calorimetry. The wx/ae starch sample had a specific surface area of 3.26 m²/g and pores on its surface with diameters ranging from 6 to 60 nm. Its water adsorption capacity was 0.278 of the weight fraction of water and its weight fraction of bound water molecules was 0.233, both of which are larger than those of wx and wild‐type (WT) starches. We suggest that the starch–water interaction is primarily determined by the morphology and nanostructure of the starch, such as the granule shape and size, specific surface area, porosity, and crystal structure, and that wx/ae starch has a greater capacity to interact with water molecules because of its unique structure.
Agid:
5856271