Impact of processing methods on glycemic indices of food products from three yam cultivars consumed in eastern D.R. Congo.

Yam (Dioscorea spp.) is a key staple food with significant nutritional and therapeutic value; however, its glycemic properties vary with genotype and processing methods. This study assessed how genetic differences and processing methods affect glycemic index of yam-based food products. Tubers from three local yam cultivars-Kasakura from Dioscorea dumetorum (Kunth) Pax, and Kitende Mauve and Bigeja, representing purple and yellow Dioscorea alata L., respectively-from eastern Democratic Republic of Congo (DRC), were boiled, blanched, and soaked before being used to make boiled yam, fufu, and bread. Yam-based food products from each cultivar were assessed for glycemic index using 10 healthy fasting individuals. Capillary blood glucose levels were measured with a glucose meter before ingestion, and at regular intervals after consuming the test food products and a glucose reference. The glycemic index was determined based on the postprandial glycemic response relative to glucose. The results showed significant differences in glycemic indices among the cultivars and processing methods, with boiling yielding the lowest indices (44.15 for cultivar Bigeja to 56.20 for cultivar Kitende Mauve). Yam fufus exhibited moderate indices, ranging from 60.00 for soaked Bigeja to 69.32 for blanched Kitende Mauve. Panification significantly diminished the yam's hypoglycemic properties. This study highlights the yam's potential as a dietary food, especially when consumed as boiled food. Future studies should focus on optimizing processing methods and screening a wider range of yam cultivars to develop low-glycemic-index products suitable for metabolic diseases prevention.