Selective Comparison of Native and Nanocrystals of White and Yellow Yam Starches

Abstract

Mild acid hydrolysis at 40 °C for 5 days was used to prepare nanocrystals of the native starches isolated from white yam (Dioscorea rotundata) and yellow yam (Dioscorea cayenensis). The shapes and granular sizes of the native starches were obtained by a scanning electron microscopy while their nanocrystals were examined through transmission electron microscopy. The nanocrystals were found to exist in the form of platelets. X-ray diffraction of the starch nanocrystals showed that they were of V-type crystalline structure whereas the native starches exhibited CB-type crystalline structure. The nanocrystals were insoluble in all the solvents used, except in chloroform, where precipitates were formed. These starch nanocrystals could be potential precursors to nanocomposites and nanoparticle-based copolymers. doi:10.14456/WJST.2015.95

Keywords

• Nanocrystals
• native starches
• solubility