(B)
Estimation of the amylose and amylopectin content in the control starch was done after the appropriate fractionation. The fractionation of bean and cassava control starch is based on the differential solubility in water–butanol ( Curá and Krisman, 1990); 5 g of milled and dried seeds were suspended in four volumes of 3% HgCl2 pH 7 at 20 °C and stirred for 1 h. The suspension was centrifuged at 3000g for 15 min, obtaining sediment that was resuspended in 1-butanol:water (1:7), autoclaved for 3 h at 1 atm and 110 °C, centrifuged at 3000g for 15 min. After that, the amylopectin was recovered in the butanol-soluble fraction and the amylose in the butanol- insoluble fraction, after the addition of three volumes of 96% ethanol. The precipitated fractions were washed, dried and weighed.