  2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center  |
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Three under-utilised sources of starch from the Andean region in Ecuador. Physico-chemical characterisations. S. SANTACRUZ (1,2), K. Koch (3), E. Svensson (1), J. Ruales (2), and A. C. Eliasson (1). (1) Lund University, Box 124, 221 00 LUND; (2) Escuela Politécnica Nacional, Box 1701 2759, QUITO; (3) Swedish University of Agric. Sciences, Box 7051, 750 07, UPPSALA.
The physico-chemical aspects of starches from Arracacha xanthorriza, Canna edulis and Oxalis tuberosa were investigated. SEM investigations showed that granules of A. xanthorriza were irregular shaped with sizes between 7 and 23 micrometres(µm), O. tuberosa and C. edulis were both ovally shaped with sizes between 20 and 55 µm and 35-101 µm, respectively. All three starches revealed a B-type X-ray diffraction pattern. The gelatinisation enthalpy investigated by using DSC was 17.8 J/g of amylopectin for O. tuberosa, 20.7 J/g for C. edulis and 18.3 J/g for A. xanthorriza, and the peak temperature of gelatinisation was 55.9°C, 61.2°C and 60.1°C, respectively. The amylose content determined by GPC after debranching with isoamylase was 4 percent(%) for A. xanthorriza, 18% for O. tuberosa, and 24% for C. edulis. The amylopectin showed different structures among the three starches with a beta-amylolysis limit of 67.6% for C. edulis, 64.5% for O. tuberosa and 56.6% for A. xanthorriza. The average chain length of the amylopectin was 22.6 for A. xanthorriza, followed by O. tuberosa with 22.4, and C. edulis with 21.9. The complexation ability of the three starches was investigated by adding SDS, and the amylose content was positively correlated with the enthalpy of the amylose-SDS complex.
Copyright 2001
The American Association of Cereal Chemists