Meeting Abstract - Poster Presentation

Differences in functional properties of starches between hard and soft wheat genotype
H. CHOI (1), B. Baik (1)
(1) Washington State University, Pullman, WA, USA
Cereal Foods World 53:A54

Gelatinization, pasting and retrogradation properties of starch significantly affect processing, cooking and textural quality as well as shelf life of many wheat-based food products. Amylose content of starch depends mainly on the genetic background of wheat and is largely responsible for variation in functional properties. To explore the differences in gelatinization, pasting and retrogradation properties of starches between wheat classes, we isolated prime starches from wheat genotypes of contrasting classes, including regular and partial-waxy starch endosperm, hard and soft, white and red, and winter and spring wheat, and determined their pasting properties using a micro-visco amylograph, syneresis during storage and hardness of gel. Six partial-waxy wheat genotypes exhibited lower pasting temperature and greater peak viscosity than 12 genotypes of regular starch. In wheat genotypes of regular starch, starch pasting temperatures of four hard white (HW) wheat genotypes ranged from 83.4 to 85.7°C, while those of seven soft white (SW) wheat genotypes ranged from 79.2 to 82.9°C. SW wheat genotypes, with the exception of one SW genotype, were lower in peak viscosity of starch than HW genotypes. Similarly, in genotypes of partial-waxy starch, three SW wheat genotypes exhibited lower pasting temperature (69.2–76.6°C) and smaller peak viscosity (201-236 BU) than three HW wheat genotypes, which had pasting temperature and peak viscosity of 78.0–80.1°C and 246-261 BU, respectively. In both regular and partial-waxy genotypes, hard white wheat exhibited greater peak temperature than hard red wheat genotypes, while differences in peak viscosity between white and red wheat genotypes were inconsistent. Syneresis and hardness of starch gel stored for 7 days at 4°C varied widely among genotypes, but the differences between hard and soft wheat genotypes were not significant. Starches of regular amylose content showed much greater syneresis and hardness of starch gels than partial-waxy starches, which ranged from 1.51 to 7.18% and 15.5 to 23.0 N in the former, and from 0.20 to 0.57% and 12.1 to 15.8 in the latter, respectively.