Comparative Study of the Physicochemical, Functional, Thermal, and Rheological Properties of Pretreated Flours From Dioscorea alata and Dioscorea rotundata

Dioscorea is a diverse group of tubers known as yams, among which D. alata and D. rotundata stand out for their socioeconomic importance. For preservation purposes, they are processed into flours, which may present technological limitations. Pretreatments such as immersion, blanching, and soaking have shown potential for improving their quality. In this context, the objective of this research was to conduct a comparative study of the physicochemical, functional, thermal, and rheological characteristics of yam flours from D. alata and D. rotundata subjected to pretreatments. Flours from both varieties were obtained by immersing them in 1.5% citric acid for 10 min, blanching them at 50°C for 3 min, and soaking them in water for 4 h. Physicochemical analysis revealed that pretreatments improve the whiteness index, while proximal analysis indicated a higher carbohydrate content. Improvements in functional properties were evident, with a retention capacity of 2.98 g/g for D. alata and a solubility and dispersibility of 9.24% and 70%, respectively, for D. rotundata . Thermally, the flours had gelatinization temperatures above 70°C and a degradation limit of 200°C, conditions suitable for cooking processes. The rheological behavior was typical of shear thinning and G´ > G´´ modules, indicating viscoelastic solid behavior, although D. alata showed the highest resistance to flow. In general, the flours presented varied characteristics that allow decisions to be made in the selection and optimization of processes and products in the food industry.