Thermal properties of starch from 62 exotic maize (Zea mays L.) lines grown in two locations

Abstract

The variability in thermal properties among 62 S3 lines derived from a high-yielding exotic corn (Zea mays) population, Antigua 1 (PI 484990), was evaluated by differential scanning calorimetry (DSC). The S3 lines were grown in Puerto Rico (1990-1991) and Georgia (1994). Separate single-kernel starch extractions for five kernels (five replicates) from each line grown in each location were performed, and the starch was analyzed. The DSC values reported included gelatinization onset (T(oG)), range (R(G)), enthalpy (ΔH(G)), and peak height index (PHI) and retrogradation onset (T(oR)), range (R(R)), enthalpy (ΔH(R)), and percent retrogradation (%R) (an indication of the stability of gelatinized starch after storing at 4°C for 7 days). Significant differences (P < 0.05) were found among the 62 lines of Antigua 1 for T(oG), R(G), and PHI and highly significant differences (P < 0.01) were found for ΔH(G). The starches from plants grown in Georgia (1994) had significantly (P < 0.05) greater T(oG), ΔH(G), and PHI but a significantly lower R(G) than those from Puerto Rico (1990-1991). These data suggest that the starch from plants grown in Georgia (1994) might have a greater degree of crystallinity than that from Puerto Rico (1990-1991). None of the retrogradation values were significantly different among starches of the 62 lines of Antigua 1 and the starches from plants grown in the two locations.