|Ng, King-Yee - IOWA STATE UNIVERSITY|
|White, Pamela - IOWA STATE UNIVERSITY|
Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 15, 1997
Publication Date: N/A
Interpretive Summary: Starch is often chemically modified before using it in food products, to give it the properties important in processed food. There are economic and health reasons to find "naturally" modified starch. Previous work has shown that exotic corn may have genes that can modify corn starch. Inbred lines from a tropical corn population and grown in two locations were tested for starch properties. The lines were significantly different from each other for their starch properties. The lines grown in Georgia were different than the same lines grown in Puerto Rico, possibly having a more crystalline structure. Results are important to starch processors who process corn grown in different locations, and breeders interested in developing corn lines with "naturally" modified starch.
Technical Abstract: The variability in thermal properties among 62 S3 lines derived from a high-yielding exotic corn (Zea mays L.) population, Antigua 1 (PI 484990), was evaluated by using differential scanning calorimetry (DSC). The S3 lines were grown in Puerto Rico (1990-91) and Georgia (1994). Separate single-kernel starch extractions for 5 kernels (5 replicates) from each line grown in each location were performed, and the starch was analyzed. The DSC values reported include gelatinization onset (ToG), range (RG), enthalpy (AHG), peak height (PHI), retrogradation onset (ToR), range (RR), enthalpy (AHR), and % retrogradation (%R) (an indication of the stability of gelatinized starch after storing at 4 degrees Celsius for 7 days). Significant differences (p<0.05) were found among the 62 lines of Antigua 1 for ToG, RG, and PHI and highly significant differences (p<0.01) were found for AHG. The starches from plants grown in Georgia (1994) had significantly (p<0.05) greater ToG, AHG, and PHI, but a significantly lowe RG, than those from Puerto Rico (1990-91). These data suggest that the starch from plants grown in Georgia (1994) might have a greater degree of crystallinity than that from Puerto Rico (1990-91). None of the retrogradation values were significantly different among starches of the 62 lines of Antigua 1 and among the starches from plants grown in the two locations.