Effect of Different Sun Drying Surfaces on the Functional Properties and Microbial Loads of Unripe Plantain Flours

Abstract

In order to test the effect of commonly used traditional sun-drying surfaces on some qualities of the product, four traditional sun drying surfaces; wooden, corrugated iron sheet, rock and cement surfaces were used to sundry unripe plantain. The sundried samples were milled to flours. Functional, pasting properties and microbial loads of the resulting flours were determined using standard methods. Values of the functional properties determined except bulk density (packed) and solubility were higher in the rock followed by samples dried on cement surface compare to others. Functional properties except oil absorption and solubility generally improved with storage. Pasting property shows that, samples dried on the rock followed by samples dried on cement surface had the highest values in terms of peak viscosity, trough and final viscosity. There was no significant difference (P0.05) in breakdown and pasting temperature. Results of the microbial loads monitored for a period of two months show that at the initial stage, flours of samples sundried on rock had the highest microbial growth while samples dried on corrugated iron had the lowest. There was no significant difference (P0.05) in others. There was increase in microbial loads of samples dried on rock and corrugated iron but decreased in others after one month of storage. After storing for a period of two months, microbial loads of samples dried on the rock and cemented surfaces increased while no growth was recorded for samples from wooden and corrugated iron. The report from this research work revealed that rock and cemented surfaces are recommended for sun drying unripe plantain for better functionality of the flour while wood and corrugated iron surfaces are recommended based on microbial load for better storability.