Optimization of processing conditions for improved functional properties of poundo flour made from precooked sweet potato tubers.

Abstract

Background: Instant-pounded yam flour (poundo flour) provides a convenient and time-saving alternative to the traditional yam pounding method. This study explores the optimization of processing conditions for poundo flour production from precooked sweet potato tubers, aiming to enhance its functional properties for improved quality and efficiency in food applications.

Results: Response surface methodology, incorporating a central composite rotatable design, was adopted to evaluate the effects of slice thickness (1-5 mm), precooking time (5-25 min), and drying temperature (40-80 °C) on bulk density (BD), swelling capacity (SC), water absorption capacity (WAC), oil absorption capacity (OAC), and gelatinization temperature (GT). High coefficients of determination (R ² values) were obtained, indicating strong relationships between the processing variables and response parameters. During optimization, BD, SC, and WAC were maximized, while OAC and GT were minimized to improve hydration, swelling and thickening behaviour, reduce oil retention, and lower energy requirements during cooking. The optimal processing conditions were identified as slice thickness of 4 mm, precooking time of 10 min, and drying temperature of 53.27 °C. The predicted values of BD, SC, WAC, OAC, and GT, under these conditions, were 0.930 g cm^-3, 0.33 g g^-1, 0.138 g g^-1, 0.376 g g^-1 and 63.92 °C, respectively. Experimental validation yielded corresponding values of 0.915 g cm^-3, 0.34 g g^-1, 0.140 g g^-1, 0.370 g g^-1 and 63.50 °C, with percentage errors below 3% for all responses.

Conclusion: The close agreement between predicted and experimental results confirms the adequacy and reliability of the developed models for predicting and optimizing the functional characteristics of the poundo flour. © 2026 Society of Chemical Industry.