Effect of different drying methods on the rehydration kinetics, physiochemical and functional properties of unripe plantain (Musa parasidiaca) flour

Abstract

Plantain (Musa parasidiaca) is a perishable fruit that needs to be processed into flour to extend its shelflife. It is therefore essential to develop specifications for drying Musa parasidiaca pulp to obtain high quality flour and reduce wastage. The study specifically examined functional properties such as bulk density, least gelation concentration, swelling power, oil absorption capacity, tapped density and pH of the unripe Musa parasidiaca flour. Additionally, the proximate composition such as moisture content, ash, crude protein, crude fibre carbohydrate and crude fat were also investigated. The results showed that the method of drying has a significant effect on the carbohydrate and moisture content of the unripe Musa parasidiaca flour. As regard to the crude protein, it was revealed that there were no significant differences between microwave dried (3.75 %) and sun dried (3.84 %) flours. Bulk density of the unripe Musa parasidiaca flour samples dried in the microwave dryer (MD), sun drying (SD) and oven dryer (OD) were 0.66 g/mL, 0.60 g/mL and 0.77 g/mL respectively. It was observed that all the three methods of drying significantly impacted on the bulk density of the unripe Musa parasidiaca flour. There were also marked differences in the rehydration ratios (RR), and the moisture diffusivities of the various Musa parasidiaca flours. The study concludes that the colour of the MD unripe Musa parasidiaca flour was significantly different from that of the SD unripe Musa parasidiaca flour.

Keywords

• Swelling power
• Microwave drying
• Postharvest loss
• Least gelation concentration