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Physicochemical characterizations of three unconventional sources of starch from the Andean region in Ecuador

Abstract:

The physicochemical aspects of three native Andean starches from cultivars Arracacha xanthorriza, Canna edulis, and Oxalis tuberosa were investigated. Scanning electron microscopic investigations showed that the granular sizes were remarkably different among the three starches. The starch granules of A. xanthorriza were irregular, with granular sizes between 7-23 μm whereas the granules of O. tuberosa and C. edulis both were oval-shaped with granular sizes between 22-25 μm and 35-101 μm, respectively. All three starches revealed an X-ray diffraction pattern of the B-type that also is reported to be typical for most kinds of tubers. The gelatinization enthalpies were 14.6 ± 0.2 J g-1 for O. tuberosa, 15.7 ± 0.2 J g-1 for C. edulis, and 17.6 ± 0.3 J g-1 for A. xanthorriza, and the peak temperatures of endothermic differential scanning calorimetry (DSC)-transitons were 55.9 ± 0.2°C, 61.2 ± 0.1°C, and 60.1 ± 0.1°C, respectively. There were no direct correlations between the gelatinization parameters and the amylose content that was found to be 4 ± 1% for A. xanthorriza, 18 ± 1% for O. tuberosa, and 24 ± 0.4% for C. edulis.