A comparative study of mango seed kernel starches and other commercial starches: the contribution of chemical fine structure to granule crystallinity, gelatinization, retrogradation, and pasting properties

Mango seed kernels (MSK) are the waste from mango processing plants; but they still contain valuable nutrients. In this study, the physicochemical properties of starches isolated from seed kernels of three Thai mango cultivars (Namdokmai, Kaew, and Chokanan), mainly used in the industry, were characterized and compared with those of other commercial starches namely tapioca, corn, low-, and high-amylose rice. MSK starches possessed a smooth-oval shape granule with average diameter of 12.90-13.20 mu m. They were higher in lipid (0.53-0.55%) and amylose (31.50-33.12%) than other starches. Amylopectin and amylose of MSK starches had a relatively low molecular weight. Amylopectin of MSK starches had higher proportion of B1 and B2 chains but lower proportion of A chain than those of other starches. These chemical properties contributed to changes in value of following properties of MSK starches: higher crystallinity (40.20-41.30%), higher gelatinization temperature (78.13-82.39 degrees C) and enthalpy (17.32-19.45J/g), higher pasting temperature (81.6-84.4 degrees C) and peak viscosity (356.2-423.8 rapid viscoanalyzer units). Amylopectin of MSK starches also retrograded to a higher extent than that of other starches. Based on their physicochemical properties, MSK starches; especially Kaew cultivar, could be a potential source of resistant starch; particularly of RS2.