Gelatinization and retrogradation of 6-year-old korean ginseng starches studied by DSC

Gelatinization and retrogradation characteristics of 6-year-old Korean ginseng starch with different grades were investigated using differential scanning calorimetry (DSC). The 1st and 3rd grade ginseng starches showed typical biphasic DSC endotherm while 2nd grade ginseng starch revealed monophasic DSC endotherm with relatively narrow transition temperature. Although Avrami exponents (n) of all ginseng starches were close to 1.0 (i.e., retrogradation of all ginseng starches at a single temperature have an instantaneous nucleation followed by rod-like growth of crystals), 1st and 3rd grade ginseng starches showed higher degree of retrogradation and faster retrogradation rate than 2nd grade ginseng starch. This indicates that 2nd grade ginseng starch has different gelatinization and retrogradation characteristics compare to 1st and 3rd grade ginseng starches, which may influence the occurrence of inner white, the main defect of red ginseng.