Fine structure of amylopectin in relation to gelatinization and retrogradation behavior of maize starches from three wx-containing genotypes in two inbred lines

Abstract

had A:B chain ratios within the range of 0.9-1.1. The A:B chain ratio of 1.5, together with the high proportion of longer chains in that sample, is consistent with the interpretation that the population of A chains in this sample contains some unusually long chains. In both lines, the starch granules from the ae wx genotype had the highest AH and Tmax for both gelatinization and retrogradation. The high AHfor the ae wx starches might be attributed to greater amounts of longer chains in these amylopectins. Except the starches from the wx genotype at 10% concentration, all of the gelatinized starch samples showed a differential scanning calorimetry endothermic peak after being stored at 4°C for seven days. Retrogradation AH was highest for the ae wx starches, both in absolute terms and as the proportion of gelatinization AH. In most cases retrogradation AH was higher (on dry weight basis) for 30% than for 10% starch; for the du wx starches, the AH at 30% starch was approximately twice that at 10%. and maltotriose to other linear fractions of debranched 3-limit dextrin (Peat et al 1956). The maltose and maltotriose represent the A chains of the native amylopectin. Alternatively, Hizukuri (1986) estimated the A:B chain ratios for several starches from