Surface characterization of cottonseed meal products by SEM, SEM-EDS, XRD and XPS analysis

Authors: He, Zhongqi; Cheng, Huai; Olanya, Modesto; Uknalis, Joseph; ZHANG, XIAODONG - Tulane University; KOPLITZ, BRENT - Tulane University; HE, JIBAO - Tulane University

Submitted to: Journal of Materials Science Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2018
Publication Date: 1/1/2018
Citation: He, Z., Cheng, H.N., Olanya, O.M., Uknalis, J., Zhang, X., Koplitz, B.D., He, J. 2018. Surface characterization of cottonseed meal products by SEM, SEM-EDS, XRD and XPS analysis. Journal of Materials Science Research. 7(1):28-40.

Interpretive Summary: The utilization of cottonseed meal as a valuable industrial feedstock needs to be exploited. In this work, the surface characteristics of the six cottonseed meal products were examined. Multiple instrumental techniques revealed the morphology and surface composition of six cottonseed meal products which differed from a commercial soy protein product. Total cottonseed protein isolate and its water and alkali soluble fractions all showed compact crystalline structures while the residues after protein extraction showed more loose and porous structures. The surface of the residues after protein extraction was characterized by the hydrocarbon (polysaccharides) features. The water-washed cottonseed meal demonstrated its surface features more similar to the polysaccharide-predominant residual samples than to the protein samples. Information derived from this work increased the understanding of the surface functional properties of cottonseed meal products, which would benefit their practical utilization.

Technical Abstract: The utilization of cottonseed meal as a valuable industrial feedstock needs to be exploited. We have recently produced water-washed cottonseed meal, total cottonseed protein, sequentially extracted water- and alkali-soluble proteins, and two residues after the total and sequential protein extractions at a pilot scale. In this work, the surface characteristics of the six cottonseed meal products were examined by scanning electron microscopy (SEM), scanning electron microscopy- energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results showed that the surface properties of the six products differed from those of a commercial soy protein flour examined comparatively in this work. The compact morphology and relative-high N composition were observed in all three protein products, with greater similarity between the total protein and alkali-soluble protein. The surfaces of the two residue products were more porous with polysaccharide features. Washed cottonseed meal possessed the surface features similar to those of the residues. In the meantime, the N-associated functional groups were under-represented in the surfaces of all samples, compared to their bulk composition. Information derived from this work increased the understanding of the surface functional properties of cottonseed meal products, which would benefit their practical utilization.