Modifying starch allows for improvements in its properties to enable improved uses in food matrices, bioplastics, and encapsulating agents. In this research, four varieties of native potato starch were modified by acid treatment, enzymatic treatment, and ethanol precipitation, and their physicochemical, structural, thermal, and techno-functional characteristics were analyzed. According to FT-IR analysis, no influence of the modified starches on the chemical groups was observed, and by scanning electron microscopy (SEM), spherical and oval shapes were observed in the acid and enzymatic treatments, with particle sizes between 27 and 36 μm. In particular, the ethanolic precipitation treatment yielded a different morphology with a particle size between 10.9 and 476.3 nm, resulting in a significant decrease in gelatinization temperature (DSC) and more pronounced crystallites (XRD). On the other hand, the enzymatic treatment showed higher values for z-potential (ζ), and the acid treatment showed lower mass loss (TGA). Acid and ethanolic treatments affected the dough properties compared to native starches. The techno-functional properties showed a decrease in the water absorption index, an increase in the water solubility index, and varied swelling power behaviors. In conclusion, the modification of potato starches through acid, enzymatic, and ethanolic precipitation treatments alters their physicochemical properties, such as swelling capacity, viscosity, and thermal stability. This in turn affects their molecular structure, modifying morphology and the ability to form gels, which expands their applications in the food industry to improve textures, stabilize emulsions, and thicken products. Furthermore, these modifications also open new opportunities for the development of bioplastics by improving the biodegradability and mechanical properties of starch-based plastic materials.

Considering the potential of biopolymers from underutilized Andean sources in Peru to improve the characteristics of edible films, this work aimed to evaluate the formation of a polymeric matrix composed of Nostoc and modified potato starch for the formulation of edible films for food coating. The effects of polymer matrix ratio and drying temperature on films obtained by thermoforming were studied, determining the water vapor permeability and mechanical properties using a multifactorial design. Additionally, thermal properties were characterized by TGA and DSC, and structural properties by FT-IR and scanning electron microscopy. The results showed that the films exhibited lower solubility, lighter hues, better water vapor resistance, higher tensile strength, and improved thermal stability with increasing modified starch content. The formulation with higher Nostoc content exhibited a more homogeneous surface according to microscopy images, and no new chemical bonds were formed by adding modified starch and Nostoc to the polymer matrix, according to FT-IR spectra. These findings are promising and suggest using Nostoc for elaborating edible films composed of native and modified starch from native Andean potatoes as bio-based materials with potential application in the food industry.