Physical properties and gelation behavior of a low-amylopectin maize starch and other high-amylose maize starches

This paper examines the effect of changes in fine structure due to hybrid breeding on gel formation and gel properties of high-amylose maize starches. Both small-strain oscillatory testing and uniaxial-compression testing ranked G' and texture/strength, respectively, in the same order of HYLON(R) V starch <HYLON(R) VII starch <low-amylopectin starch (LAPS). The starch gels became more rigid and stronger as amylose content of the hybrids increased from HYLON V starch to LAPS. It was also noted in these studies that LAPS had the quickest onset of gelation and HYLON V starch had the slowest. The effect of preparation temperature on gel properties was also studied by cooking high-amylose starches at 250 degrees, 270 degrees, 290 degrees, 310 degrees, 330 degrees F in a mini-jet cooker with minimal steam Temperature of jet cooking had an impact on the rate of sol-to-gel transformation of the starches, which in turn influenced the final gel properties. All three hybrids were strongest (highest fracture stress and strain values) when prepared at 270 degrees F. HYLON V had the narrowest cooking tolerance forming self-supporting gels from 270 degrees to 310 degrees F, while LAPS was the most robust, forming acceptable gels throughout the range of temperatures tested. (C) 1998 Academic Press Limited.