Metal analyses of ash derived alkalis from banana and plantain peels (<i>Musa spp.</i>) in soap making

Abstract

The objective of this work was to determine the metal content of plantain and banana peels ash derived alkali and the possibility of using it as alternate and cheap source of alkali in soap industry. This was done by ashing the peels and dissolving it in de-ionised water to achieve the corresponding hydroxides with pH above 12. The solution was then analyzed using Atomic Absorption Spectroscopy (AAS). The analytical measurements were carried out in triplicate and the multi elemental solution was used for calibration of equipment. The abundance of essential metals was in these orders in both the banana and plantain alkalis: K > Fe > Ca > Mg > Mn > Zn > Na and Fe > K > Ca > Mg > Zn > Mn > Na, respectively. The presence of other metals besides K and Na at higher concentrations limits the foamability of the soaps but could be adapted as thickeners and emulsifiers in greases. The concentrations of elements with health risk in the ash derived alkalis are within the allowable range of the Commission of European Communities (2008) limit.

Key words: Banana, plantain, ash derived alkali, major elements, minor elements.