Valorisation of rejected unripe plantain fruits of Musa AAB Simmonds: from nutritional characterisation to the conceptual process design for prebiotic production

The increasing consumption of plantain fruits with specific quality standards generates high agricultural waste. This work aimed at valorising the rejected unripe pulp of Dominico-Hartón plantain fruits (Musa AAB Simmonds). The pulp was characterised physico-chemically, thermally and functionally. The data gathered experimentally and collected from different databases were used to design a production process of isomalto-oligosaccharides (IMO) syrup. The plantain flour contains high levels of starch (87 ± 2%) and amylose (31.2 ± 0.8%). The flour showed stability at high temperatures (pasting temperature of 79.26 ± 0.02 °C), allowing its use in high temperature processes. In vitro gastrointestinal digestion of the plantain flour showed that when cooked, the glycemic index of the flour increased from 47.7 ± 2.2 to 84.2 ± 1.8, while its resistant starch content only slightly decreased from 71.7 ± 1% to 52.6 ± 2%, suggesting that this type of flour preserves high content of dietary fibre after digestion. The conceptual process design showed that 24.48 g of IMO are theoretically obtained from 53.24 g of plantain flour maltose. These results suggest that the rejected plantain pulp holds high potential as an ingredient for the production of prebiotic compounds such as IMO.