Effects of cassava variety and growth location on starch fine structure and physicochemical properties

Apparent amylose content (AAC), resistant starch (RS) content, pasting, gelatinization, retrogradation properties, and fine structural parameters amongst starches from five Thai cassava cultivars grown in two different locations were determined. Results indicated that significant differences among different varieties were found for most traits. The AAC, gelatinization onset (T-o) and peak temperature (T-p), the ratio of peak heights of amylopectin (h(AP2)/h(AP1)) and chain length distribution (CLD) of amylopectin fa, fb2, fb3 and average CLD ((X) over bar) were mainly affected by genotypic effects. The peak viscosity (PV), breakdown (BD), molecular size of amylose (R-h,R- AM) and amylopectin (R-h,R- AP), average molecular size ((R) over bar (h)), the position of amylopectin peak (X-AP1) and fb1 were mainly affected by environmental effects. The effects of the genotype x environment interaction were significant for BD, R-h,( AM), R-h,R- AP, h(AP2)/R-Ap1 and fb2 values. RS was negatively correlated with the amount of amylopectin fa chains. PV and BD were affected by R-h,R- AM, R-h,R- AP, X-AP1, X-AP2, and the amount of fb1 chains. T-o and T-p were affected by X-Ap1, X-Ap2, fb1 and fb2. These results enhance our understanding of the structure-function relations of starches and are useful for the application of starch in the food industry and for breeding programs to improve the cassava starch quality.