Effect of selected physico-chemical treatments on properties of banana flour

Abstract

This study determined the effect of freeze-thaw cycles and addition of glycerol mono-stearate on the functional and nutritional properties of flour from two banana varieties. Mature green bananas of Mpologoma and Kibuzi varieties were peeled, sliced, dried and milled into flours. The flours were separately subjected to freeze-thaw cycles and glycerol mono-stearate treatments and their effects were evaluated. The pasting, functional and nutritional properties as well as starch digestibility of the treated banana flours were determined. Freeze-thaw cycles resulted in an increase in water absorption capacity (WAC) and water holding capacity (WHC) for both Kibuzi and Mpologoma banana varieties. The same treatment resulted in a significant decrease (p<0.05) in oil absorption capacity (OAC) and solubility for both varieties. The Peak, breakdown, setback and final viscosities for both varieties increased with an increasing number of freeze-thaw cycles. The Swelling power and solubility for Kibuzi and Mpologoma flours decreased (p<0.05) with increasing concentration of glycerol mono-stearate while the WHC and WAC for both varieties increased under the same treatments. Setback and final viscosities increased (p<0.05) with increasing glycerol mono-stearate concentrations while peak and breakdown viscosities decreased under the same condition. The increase in setback viscosity was higher with glycerol mono-stearate than freeze-thaw cycles treatment. Rapidly digestible starch levels for Kibuzi and Mpologoma reduced when 2.5% glycerol mono-stearate was applied and the same treatment led to an increase in resistant starch for both varieties. Therefore, freeze-thawing treatment can be used to produce ingredients of banana flour that can be used where highly vicious paste is needed while 2.5% glycerol mono-stearate could be suitable for producing a less digestible ingredients from banana flour.