Annealing of maize starch

A comparison was made between the annealing characteristics of commercial w axy, normal and amylomaize starches. The waxy and normal starches responded similarly to annealing where improved registration of amylopectin double h elices is proposed, with perhaps optimisation of hydrogen bonding along the full length of individual helices. This is attributed to similar amylopect in crystalline structure of these starches. It is considered unlikely that the free amylose (FAM) forms any significant numbers of amylose-amylose or amylopectin-amylose double helices throughout its length, but may randomly form some double helical regions in the crystalline shells created essentia lly by the amylopectin. Single amylose helices are also considered unlikely . Probably lipid complexed amylose (LAM) is excluded from the amylopectin c rystallites and is primarily located in amorphous shell regions (between cr ystalline shells) and consequently affects hydration (and glass transition, Tg) of these regions. in amylomaize starches, however, the larger amylopec tin chain lengths, broad gelatinisation endotherm, leaching characteristics and double helix content (by NMR) indicates that FAM does here play a sign ificant part in the crystalline regions of the starch. Annealing of amyloma ize crystallites probably reflects enhanced registration (and possibly comp artmentalisation) of amylopectin-amylopectin, amylopectin-amylose and amylo se-amylose helices. (C) 2000 Elsevier Science Ltd. All rights reserved.