Isolation and molecular characterization of makal (Xanthosoma yucatanensis) starch

Starch was isolated from a non-conventional source: makal (Xanthosoma yucatanensis) and molecular characteristics were determined using X-ray diffraction, light scattering and chain length determination. The granules had an oval shape with sizes between 8 and 20 mu m, with an average size of 12.4 mu m. Amylose content was 22.4% and amylopectin content 77.6%. The granules presented a C-type X-ray diffraction pattern, with a degree of polymerization (DP) of 5-19 for branch chain lengths and an average molar mass of 5.4 x 10(6) g/mol. The R-H and the R-G was 61.7 and 92.7 nm, respectively. Gelatinization temperature was 72.6 to 84.2 degrees C and transition enthalpy was 15 J/g, which may be related to the X-ray diffraction pattern and to the small granule size of makal starch. The retrogradation of makal starch increased during storage.