Morphological and thermal characterization of native starches from Andean crops

We have characterized and compared the morphological and thermal properties exhibited by starches from different Andean crops. Starches were extracted from tubers, root, fruits, and other starch containing parts of different plants. Morphological characterization was carried out by means of light optical microscopy. Thermal analysis was performed by DSC. The morphological properties of starch granules as well as the gelatinization parameters vary considerably among plants sources. Feret's diameter of granule starches is related to the part of the plant from which starch is obtained corresponding the largest starch granules (approximate to 42.5 mu m) to tuber sources, whereas, smallest granules to root sources (approximate to 8.9 mu m). The specific enthalpies of gelatinization were in the range 9-18.7 J/g. An inverse correlation between specific enthalpies and specific surface area (SSA) for starch with water content of 75% indicates that starches with higher SSAs need less energy to complete the gelatinization process than those with lower SSAs. The results show that starches from Andean crops could be used as raw material for the production of new starch-based thermoplastics.