Physicochemical characterization of isolated nanocrystals in starch and isolated rice starch: A new perspective
Porfirio E Martinez-Munoz1, Elsa Gutierrez-Cortez2, Margarita I Hernandez-Urbiola1
1Universidad Nacional Autónoma de México, Centro de Física Aplicada y Tecnología Avanzada, Campus Juriquilla, 76230 Querétaro, Qro., Mexico.
Abstract:
In this work, isolated rice starch (IRS) (Oryza sativa cv. large grains) from the macro to the nanoscale is investigated. IRS contains P, Mg, K, Mn, Na and Ca as well as traces of Fe, Si, Al, and Zn. The internal structure of IRS consists of nanometric rings with a thickness of 50-70 nm containing nanocrystals isolated by an acidic method (INCs). The X-ray pattern in starch is generated by nanocrystals with orthorhombic crystal structure confirmed by transmission electron microscopy images (3-6 nm and a length of 15-25 nm). After gelatinization this pattern appears amorphous. IR and Raman of IRS and isolated nanocrystals show that the spectrum of starch is the superposition of their individual components. TEM-energy dispersive spectroscopy showed that the INCs are composed of C, O, and H, and contain traces of Ca, P, Mg, and Na.
