Effect of prolonged cooking on pro-vitamin A levels of biofortified East African highland bananas.

Genetically modified East African highland bananas (EAHBs) with elevated levels of pro-vitamin A (pVA) have been developed to address vitamin A deficiency (VAD) in Uganda. The green, mature fruits of EAHBs are traditionally prepared into "matooke," a soft, savory dish made by peeling, steaming, and mashing the fruit. Biofortifying such a culturally embedded food offers an effective approach to improving nutrition, particularly among vulnerable populations. Field trials of pVA-biofortified EAHBs have been conducted at four locations across Uganda, with data collection nearing completion. However, the effect of prolonged cooking, a common traditional preparation method, on pVA carotenoid retention had not been evaluated. This study investigated the retention of β-carotene equivalents (β-CE) during extended cooking in two elite events, each of hybrid M9 and Nakitembe. After 1 h of cooking, β-CE concentrations declined significantly in both wild-type and biofortified lines. Further cooking, up to 8 h, did not result in additional significant losses. By the eighth hour, β-CE levels remained above the target threshold of 20 µg/g dry weight (DW) in one M9 event (21.7 µg/g DW) and both Nakitembe events (28.7 and 27.6 µg/g DW), compared to 12.8 and 17.6 µg/g DW in their respective wild-type controls. This confirms that the biofortified bananas can deliver meaningful nutritional benefits under customary preparation methods. These results are not only pivotal for selecting final lead and backup events but also provide compelling evidence of trait stability, further supporting the case for deployment of biofortified EAHBs to improve public health outcomes in East Africa.