Proximate composition, rheological and sensory qualities of plantain (Musa parasidiaca) flour blanched under three temperature regimes

Abstract

The physicochemical, pasting and sensory properties of plantain flour blanched under three temperature regimes were studied. Plantain fruit fingers were washed, hand-peeled and manually sliced into cylindrical pieces of 2 mm thickness. Blanching was carried out on the sliced samples in hot water at 60, 80 and 100°C and dried in the air oven at 65°C (24 h), while the un-blanched sample served as the control. They were milled in a hammer mill, packaged in polyethylene bags and stored in a refrigerator for further analysis. Results of analysis showed that Blanching at 60, 80 and 100°C all had significant lower moisture contents (P 0.05) from each other. On the basis of the pasting properties the peak viscosity was lower for the blanched samples (410.0 and 511.92 RVU) than the control sample (543.42 RVU). The final viscosity was highest for the control un-blanched plantain (UBPco) flour (409.33 RVU), while it ranged between 320.42 and 407.75 RVU for the blanched samples. Blanching resulted in a decrease in the bulk density of the plantain flour. Emulsion capacity decreased from 39.84% for the control sample to a range of 30.45% for sample blanched at 60°C to 17.86% for sample blanched at 100°C. Sample blanched at 60°C was scored best for taste. Samples blanched at 80 and 100°C were rated the best for colour followed by that of control and sample blanched at 60°C. The Control and the sample blanched at 60°C were rated the best in term of texture followed by that blanched at 80°C. These results showed that blanching of plantain before drying into flour had significant improvement on the physicochemical, pasting and sensory qualities of its flour. Key words: Plantain, flour, blanching, functional and pasting properties.