Evaluación de las propiedades proximales, estructurales, morfológicas fisicoquímicas y de digestibilidad in vitro en mezclas de harinas de ñame y batata

Abstract

Yam (Dioscorea spp.) and sweet potato (Ipomeas batata) flours must be treated through modification processes because they have limitations in their physicochemical and structural properties for use in agri-food matrices. This study aimed to evaluate the effect of different proportions of flours on the proximate, structural, morphological, physicochemical, pasting, and in vitro digestibility properties of yam and sweet potato flour blends. Flours were obtained by drying the tubers with hot air at 55 °C, and mixtures were prepared at 25:75, 50:50, and 75:25 w/w sweet potato and yam flour proportions, respectively. The yam starch granules were spherical, oval, irregular, and larger than those of sweet potatoes, which are ovoid and flared. Furthermore, yam and sweet potato granules presented with type-B and type-A diffraction patterns, respectively, which, together with the starch content, amylose, non-starch components, and their molecular interactions, influenced the decrease in the molecular order and degree of crystallinity of the flour blends, without altering the morphological characteristics of the simple flours. Additive and non-additive effects were observed on flour blends’ swelling power and water absorption capacity. Likewise, breakdown and setback viscosity increased, which decreased thermal stability, increased the tendency to retrogradation, and elevated the fractions of rapidly digestible starch and resistant starch. These results suggest the high potential of flour blends in preparing baked products from the Caribbean Region, such as white bread, cookies, and cakes.