An improved approach for evaluating the semicrystalline lamellae of starch granules by synchrotron SAXS

Binjia Zhang; Fengwei Xie; David K Wang; Siming Zhao; Meng Niu; Dongling Qiao; Shanbai Xiong; Fatang Jiang; Jie Zhu; Long Yu

doi:10.1016/j.carbpol.2016.12.002

An improved approach for evaluating the semicrystalline lamellae of starch granules by synchrotron SAXS

Carbohydr Polym. 2017 Feb 20:158:29-36. doi: 10.1016/j.carbpol.2016.12.002. Epub 2016 Dec 2.

Authors

Binjia Zhang¹, Fengwei Xie², David K Wang², Siming Zhao³, Meng Niu³, Dongling Qiao⁴, Shanbai Xiong³, Fatang Jiang⁵, Jie Zhu⁶, Long Yu⁷

Affiliations

¹ Laboratory of Environment Correlative Dietology (Ministry of Education), College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou 510640, China.
² School of Chemical Engineering, The University of Queensland, Brisbane, Qld 4072, Australia.
³ Laboratory of Environment Correlative Dietology (Ministry of Education), College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
⁴ Glyn O. Philips Hydrocolloid Research Centre at HUT, Hubei University of Technology, Wuhan 430068, China. Electronic address: qdttkl@163.com.
⁵ Glyn O. Philips Hydrocolloid Research Centre at HUT, Hubei University of Technology, Wuhan 430068, China.
⁶ College of Chemistry and Environmental Engineering, Dongguan University of Technology, Dongguan 523808, China.
⁷ Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou 510640, China.

PMID: 28024539
DOI: 10.1016/j.carbpol.2016.12.002

Abstract

A fitting method combined with a linear correlation function was developed as an improved approach for the SAXS analysis of the semicrystalline lamellae of starch granules. Using a power-law function with two Gaussian plus Lorentz functions, the SAXS pattern was resolved into sub-patterns of the net lamellar peak and the power-law scattering plus scattering background (PL+B). The ratio of the net lamellar peak area (A_peak) to the total scattering area (A_total) was proposed equal to the proportion of the lamellae within the starch granule (P_SL). Along with this fitting method, we obtained a better profile of linear correlation function, with the elimination of the interference of non-lamellar amorphous starch (i.e., amorphous growth rings). Then, we could accurately calculate the lamellar parameters, e.g., P_SL, the thicknesses of semicrystalline (d), crystalline (d_c) and amorphous (d_a) lamellae, and the volume fraction (φ_c) of crystalline lamellae within semicrystalline lamellae. Quantitative analysis revealed that P_SL was positively correlated with the crystallinity (X_c) of starch. It was confirmed that the distribution of lamellar thickness was more important than the starch botanical origin in affecting the validity of the developed fitting method. We also proposed a criterion to test the validity of the proposed method. Specifically, the total SAXS pattern should be mostly tangent to the profile of PL+B at a high q tail (close to 0.2Å^-1).

Keywords: Granule; Methodology; Semicrystalline lamellae; Starch; Starch (PubChem CID: 24836924); Water (PubChem CID: 962); X-ray scattering.

MeSH terms

Scattering, Small Angle
Starch / chemistry*
Synchrotrons
X-Ray Diffraction

Substances

Starch