ARS | Publication request: PASTING AND THERMAL PROPERTIES OF POTATO AND BEAN STARCHES.

Submitted to: Starch
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 2, 1997
Publication Date: N/A

Interpretive Summary: One of the applications of starch is the manufacture of starch noodles which are widely consumed in Oriental countries. Mung bean starch is considered the raw material of choice for starch noodle preparation. For this investigation, starch from two potato genotypes, that had been successfully used to prepare starch noodles in a previous study, commercial potato starch and the starch from two types of legumes (navy and pinto beans) were used to study their pasting characteristics and compare the results to mung bean. Through this study, a better understanding of the pasting characteristics and thickening properties of the starches could lead to improvements in starch noodles made from other starches. Because this product is heated during and after processing, and aged during storage the thermal properties are very important.

Technical Abstract: Starches from potato (Mainechip, ND 651-9 and Commercial) and Navy and Pinto bean were isolated and the pasting and thermal properties examined. Analysis by Rapid Visco-Analyzer (RVA) showed potato starches had lower pasting temperatures, higher peak viscosity, and lower setback than bean starches. High intrinsic viscosity values obtained for the potato starch indicated higher than average molecular weight for the potato starches compared to the bean starches. Characterization of thermal (gelatinization and retrogradation) properties of starches by differential scanning calorimetry (DSC) showed that potato starches had sharp, well- defined gelatinization thermograms, while bean starches had broad, shallow thermograms with higher peak temperature (Tp). Potato starches required higher gelatinization enthalpies than bean starches. In comparison with gelatinization, the retrogradation thermograms of starches stored at three different temperatures (23, 4 and -10 deg C) were broader and occurred at the lower temperatures. Compared to potato starches, Navy and pinto bean starches showed a higher retrogradation enthalpy at 4 and 23 deg C storage temperatures, but a lower enthalpy at -10 deg C.