Physicochemical drivers of resistant starch and comparative suitability of East African Highland cooking banana cultivars ( <i>Musa acuminate, AAA</i> ) 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.