Evaluation of particle size, flowability and thermal properties of formulated composite wheat-sologold sweet potato flour for baked products

Abstract

This paper attempts to formulate a composite wheat-sologold sweet potato flour that would have good texture, water absorption, dough rheology and heat transfer required for quality baked products. In this study, a completely randomized design was used to determine the best blend of composite flour, followed by the evaluation of its particle size, flowability and thermal properties. The results showed that a lower mean diameter of sologold sweet potato flour would enhance even distribution (mixing) with the wheat flour. Thus, having a thoroughly mixed composite flour with recommendable consistency, hydration rate, texture, flowability and heat transfer. The Carr index and Hausner ratio of the flour samples were within the range 5 to 15% and 1.0 to 1.1, respectively of flour that exhibits free-flowing properties. Furthermore, the range of the composite samples' moisture content was 11.90 to 9.60% db, bulk density 480 to 390 kg m-3, specific heat capacity 2.10 to 1.95 KJ kg-1 K-1, thermal conductivity 0.15 to 0.11 Wm-1 k-1, and thermal diffusivity 0.09 to 0.06 m2 s-1. These values further indicate that the developed composite flour has the potential to enhance efficient quality processing, stability, and safety of the baked products. Key words: Particle size, flowability, thermal properties, wheat flour, sologold flour.