Physicochemical drivers of resistant starch and comparative suitability of East African highland cooking banana cultivars (Musa acuminate, AAA) for food industry applications

Abstract

East African Highland Cooking Bananas (EAHCB), constituting 70% of Uganda’s banana production, represent an abundant and sustainable starch source for the food industry. However, their low amylose content (13–14%) contradicts the high resistant starch (RS) content (57–68%). This study evaluates four cultivars Mpologoma, Bukumu, Mbwazirume, and Enyeru for physicochemical and structural properties, and in vitro digestibility with respect to industrial suitability. Starch yields varied (10–20%), with Bukumu highest and Mpologoma lowest, influenced by pulp moisture and A-genome prevalence. Granule sizes ranged 12.9–21.8 μm, exhibiting B-type crystallinity. Despite low amylose, Enyeru showed highest RS (68%), low rapidly digestible starch, and optimal pasting temperatures (75–83 °C), revealing crystalline structure, amylopectin chain length distribution, and granule morphology as primary digestibility influencers. These properties position EAHCB starches as potential thickeners, low-GI functional ingredients, and RS sources matching modified corn/cassava starches. Enyeru emerges as the best cultivar for functional food applications like food for diabetic patients. These findings call for targeted breeding for enhanced RS/crystallinity and in vivo validation.