Caracterización nanoscópica superficial de películas de almidón extraído de tubérculos andinos

Abstract

Biopolymers are an alternative to synthetic polymers. In particular, starch-based films have a huge research potentiality: they are non-toxic, easily degradable, use green chemistry, and can be obtained from many different natural sources. In order to use them for practical applications it’s important to understand the ultimate causes of their useful macroscopic properties, and they may be found at the nanoscopic scale. Here we present analysis performed by atomic force microscopy, characterizing the nanoscopic topographic surfaces of samples extracted from the Andean tubers melloco (Ullucus tuberosus), mashua (Tropaeolum tuberosum), oca (Oxalis tuberosa) and potato (Solanum tuberosum). Measurements revealed significant differences among the films extracted from these tubers. These results were contrasted to macroscopic measurements such as moisture content, total soluble matter, elastic properties, opacity and IR absorption spectra. Phase contrast segregation and topography AFM tapping images permitted the correlation. Hence, we could relate those samples with granular and phase segregations at the nanoscale to the less elastic forces and water affinity.