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Thermal and textural characterization of corn starch from the Argentinean germplasm. K.
SEETHARAMAN (1), A. Tziotis (1), F. Borras (2), P. J. White (1), M. Ferrer (2), and J. Robutti (2). (1)
Department of Food Science and Human Nutrition, Ames, IA 50011; (2) Instituto Nacional de Tecnologia
Agropecuaria (INTA), Pergamino, Argentina.
This project was a collaborative effort with INTA to identify corn
accessions from the Argentinean germplasm with unusual starch properties. The objective of this project,
therefore, was to screen and characterize the starch properties of several accessions from the germplasm for
further breeding potential. The screened accessions (35 total) were separated into two categories, "Original"
and "PABBC". The "Original" accessions were obtained directly from the wild, whereas the "PABBC"
accessions were regrown at the experimental research station in Pergamino, Argentina. Corn accessions
were screened initially using Differential Scanning Calorimetry (DSC) for unusual thermal properties of
starch from single corn kernels. Results from these screenings revealed more variability in the thermal
properties of starch from the "Original" accessions than from the "PABBC" accessions. From this pool, 12
accessions with the most unusual properties, such as high or low starch content, amylose content or DSC
characteristics, were selected for further characterization to identify differences in functional properties
using a Rapid Visco Analyzer (RVA) and a Texture Analyzer (TA-XT2). The functional properties of the
unusual starches were significantly different from the control starch (Mo17 inbred). RVA pasting
temperatures of the unusual starches ranged from 75°C to 85°C; RVA setback ranged from 72 to 115 RVU,
and the increase in TA-XT2 firmness of the starch gels ranged from 22 to 38% following 7 days at
refrigeration temperature.
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