Physicochemical and structural characterization of starches from Andean roots and tubers grown in Colombia.

The preservation of Andean roots and tubers (ART) depends on the recognition of their health-promoting and nutritional metabolites and their transformation into other products such as starches. The objective of this study was to determine the physicochemical and structural properties of native starches obtained from Canna edulis K., Oxalis tuberosa M., and Ipomoea batatas L. from the Colombian Andean agroecosystem. The physicochemical properties of starches were determined by traditional methods of analysis. The thermal properties were determined by gravimetric thermal analysis (TGA) and differential scanning calorimetry (DSC), while the structural characteristics were studied with X-ray diffractometry and infrared spectrometry. The ART showed a starch yield of between 53.3% and 75.4% (dry basis) and amylose content between 28.4% and 35.6%. Starches from I. batatas showed the highest percentage of amylose, lowest gel clarity, lowest water absorption index, and highest gel temperature. X-ray diffractograms showed a type A crystallographic pattern for I. batatas starch, and a type B pattern for C. edulis and O. tuberosa starches, while infrared spectra (FTIR-ATR) corroborated the structural characteristics of each type of starch. The results suggest that starches from Andean resources can be used as a substitute for traditional starches from corn and potato. In addition, their amylose content makes them potential sources of resistant starch and dietary fiber.