Effect of peeling and blanching on proximate compositions, mineral profile, physico-chemical and anti-nutritional properties of plantain (Musa AAB) flours

This study aimed to evaluate the effect of peeling and blanching on proximate composition, physico-chemical and anti-nutritional properties and some mineral profile of plantain (Musa AAB) flours. Matured green plantain was peeled and sliced into 5mm-thick pieces(PUF), peeled, sliced and soaked in boiled water (100oC) for 10mins(PBF), sliced unpeeled(UUF), and sliced unpeeled and soaked in boiled water (100oC) for 10min (UBF). Slices were dried at 65 ±1.5oC for 8h, and milled into flour (< 212µm). Flour samples were evaluated for proximate composition, functional, pasting and anti-nutritional properties and mineral profile. There were significant (p<0.05) differences among the flours for most parameters evaluated. Ash and fibre were higher in unpeeled flours, while carbohydrate reduced. Unpeeled flours had significantly (p<0.05) higher functional, but lower pasting properties compared to peeled flours, which had significantly (p<0.05) lower anti-nutritional factors compared to unpeeled samples, with values of 1.25-2.69 mg/g, 3.15-4.74 mg/100g, 8.20-10.95 mg/g, 8.85-12.20 mg/g and 1.20-2.39mg/100g for phenols, phytate, tannins, oxalate and trypsin inhibitors  respectively, which were within safe levels. Unpeeled flours had significantly (p < 0.05) higher oxalate:calcium and [Ca]:[Phy]/[Zn] molar ratios and mineral safety index values than peeled flours, which were lower than maximum safety thresholds. Peeling and blanching had significant effect on most parameters evaluated, with peeling producing greater effect than blanching.