Encapsulation of Banana phenolics using modified Matooke (East African Highland Cooking Banana - AAAEA) starch

Abstract

The main aim of this research was to explore possibility of utilisation of the vast amounts of banana waste through extraction of phenolic compounds due to their potential functional properties as well as investigate the possibility of diversifying banana starch applications by testing its application as a wall material in the production of stable phenolic encapsulates. The extraction efficiency of different solvent systems with regards to the banana polyphenols in roasting bananas plantain type (Musa acuminata) AAB genotype) known locally as Gonja and the cooking/ juice type bananas (Musa acuminata) ABB genotype known locally as Kivuvu was determined. Results for total polyphenolic content (TPC), phenolic compound profile and antioxidant activity (AA) of these banana varieties at different maturity levels was done for pulp and peel and the findings depicted that the bananas under study had a high antioxidant activity irrespective of their maturity and plant part.

Five cultivars of the East African Highland Banana (Musa accuminata AAA- EA) were selected for the starch modification study. Initially, characterisation of starch from these banana cultivars was done and the compositional, granular and molecular characteristics of all the five cultivars did not differ significantly. The modification of banana starch in this study involved use of chemical (HCl) and physical (heat) means to produce modified banana starch. The results suggested that banana starch has quality attributes that could give it a place in the commercial starch industry, both as native starch and as modified starch.

In this work, microencapsulation of banana polyphenols was successfully performed using the frequently used wall material for encapsulation (maltodextrin) as well as a novel material (modified banana starch) that had never been used for encapsulation before. Further, the banana polyphenols according to the available literature had also never been microencapsulated. The efficiency of the production of the banana phenolics powder was characterized by product recoveries higher than 50% for certain experimental conditions. The banana phenolics powder extracts obtained from modified banana starch of 5% gave comparable results to 10% maltodextrin in terms of yield, TPC and AA.