Comparative Analysis of Functional Properties and In vitro Digestibility of Raw and Boiled Yam (Dioscorea spp.) Flours

Abstract

Background: Yams (Dioscorea spp.) are highly perishable food crops. Processing them into flour after harvest is an effective preservation strategy that reduces post-harvest losses, thereby contributing to food security and offering a viable alternative to increasingly costly wheat flour. Yam flour is a shelf-stable product, easy to package, and versatile in culinary applications. However, the functional properties and in vitro digestibility of raw and pre-cooked (boiled) yam flours remain insufficiently explored. Aim: This study assessed the effect of boiling on the functional properties and digestibility of flours derived from three yam varieties (“Kponan”, “Krenglè”, and “Bètè-bètè”) using standard analytical methods. Methodology: The functional properties (water and oil absorption capacity) of raw and boiled yam flours were determined using the methods described by Gampoula et al. (2020), the hydrophilic-lipophilic ratio was then calculated using the formula proposed by Njintang et al. (2001). The in vitro digestibility of samples was determined according to the procedure of Colas & Attias (1975), with slight modifications. Results: Both raw and boiled yam flours exhibited high water absorption capacity, with boiled flours particularly from “Kponan” and “Bètè-bètè” showing a notably hydrophilic nature. In contrast, oil absorption capacity was consistently higher in all raw flours. Digestibility analysis revealed that boiled flours, especially from “Kponan” and “Bètè-bètè”, showed slower starch hydrolysis, suggesting increased resistance to enzymatic breakdown. Conclusion: These findings highlight the promising functional characteristics of both raw and boiled yam flours for use in diverse food products, including breads, pastries, doughs, and infant formulas. Moreover, the reduced digestibility of boiled “Kponan” and “Bètè-bètè” flours suggests potential applications in the formulation of functional foods suitable for diabetic diets.