The objective of the study was to evaluate through some microscopic techniques and light diffraction the granular organization of the grain of the cassava starch (Manihot esculenta C). In order to perform the study, some optical and electronic microscopy techniques were used; such as, conventional illumination with incandescent light, Polarized Light (PLM) and Differential Light Interference (DLIM), as well as; the techniques of Scanning Electronic Microscopy (SEM) and Transmission Electronic Microscopy (TEM), finally using the Laser Diffraction analysis (LD). The results indicate that the cassava starch displayed elipsoidal-truncated (oval-truncated) and round forms, with some deformities and diversity of sizes that vary between 6 and 17 μm, and between 21.4 and 23.2 μm, presenting a bimodal distribution. The external cover of grains, observed by SEM, shows a smooth texture, without pores presence and with almost intact external surface, which indicates a efficient extraction process, without affecting the characteristics of the material and the its nature. In contrast, with TEM, the revealed internal grain structure suggests the presence of internal channels, with a numerous tiny round structures adhered to itself and quite close to the structure suggested, as channels. By using the microscopic techniques: PLM, DLIM and SEM, it can be concluded that the cassava starch is a native granule without gelatinization, revealing that their functional properties have not been altered during the extraction process. Additionally, it can be noted that it was an efficient process, due the absence of impurities. The presence of channels defined by TEM, should indicates the form of penetration of the chemical reagents inside of the granular structure when chemical techniques of modification are applied. The information defined in relation to the granular structure of the starch of cassava in this work is of importance as base to explain his functional properties.
|Translated title of the contribution||Microscopic techniques and of light dispersion used in the evaluation of the structure of the native starch of yuca (Manihot esculenta C)|
|Number of pages||9|
|State||Published - 2009|