The occurrence of anti‐nutritional constituents in plants is an important factor that negatively affects bioavailability of nutrients and effectiveness of plant‐based foods in complementary feeding in rural areas in developing countries. However, proven methods that improve bioavailability of nutrients and tailored for application in processing complementary foods among rural communities are largely lacking. This study examined the efficacy of a traditional malting technology practiced by the Acholi ethnic community of northern Uganda to improve protein digestibility and bioavailability of iron and zinc from millet–sesame–soy composite containing 200, 300, and 550 kcal meant for complementary feeding of children aged 6–8, 9–12, and 13–23 years old, respectively. The technology involves washing and soaking of ingredients for 12 hr; malting ingredients individually for 48 hr with water changed after every 6 hr; and sun‐drying malted ingredients for 72 hr. Results showed that the level of anti‐nutritional factors significantly reduced (p ≤ 0.05) in all the composite formulae except the content of total phenolics in 200, tannins in 300 and 550 kcal, composite formula, respectively. In vitro protein digestibility significantly improved (p ≤ 0.05) in all the composite formulae except in the 200 kcal formula. Iron bioavailability significantly increased (p ≤ 0.05) in all the composite formulae except in the 550 kcal energy category. Improvement in zinc bioavailability was only observed in the 300 kcal formula. However, there were significant reductions (p ≤ 0.05) in the level of caregiver preferences for sensory properties and overall acceptability of the composites. These results demonstrate that the traditional malting technology has potential to improve nutrient bioavailability in plant‐based foods but requires improvement in order to increase its efficacy and mitigate negative effects on sensory appeal.

Iron deficiency is a major public health challenge affecting the health of about 18 and 13.8% of children and women globally, respectively. About 43% children and 29% women in sub-Saharan Africa suffer from Iron Deficiency Anemia. In Uganda, recent demographic health statistics indicate that the prevalence of anaemia among children of 6-59 months stands at 53%; while that for women of child bearing age stands at 32%. Biofortified iron-rich bean varieties have been developed and adopted in Uganda to contribute to alleviation of iron deficiency challenges. The objective of this study was to investigate the effect of traditional malting technology on nutritional quality of biofortified iron-rich beans (Phaseoulus vulgaris L.). The study examined the effect of the traditional malting technology on: (i) the contents of anti-nutritional factors (phytates, oxalates, polyphenols, tannins, trypsin inhibitor activity); (ii) digestibility of protein and bioavailability of iron and zinc; and (iii) retention of proximate constituents and mineral micronutrient contents in bean varieties. We used three bean varieties, namely NAROBEAN 1, hereafter referred to as NB1, NAROBEAN 2 (NB2), and NAROBEAN 3 (NB3), all of which are widely produced and consumed in Acholi sub-region. Application of paired t-test revealed that the traditional malting technology reduced only the content of oxalates by 42.3-54.8 % and trypsin inhibitor activity by 6.2-34.6 %, from the three varieties. The content of total phenols was reduced by 22.3 % only in NB 1 (P< 0.05). The traditional malting technology improved protein digestibility for the three varieties by 38-43.6 % (P< 0.05). Bioavailability of iron improved from in NB1 by 26.7 % and NB2 by 11.5 %; while that of zinc improved for only NB2 by 51.5 % (P<0.05). The contents of micronutrients and proximate constituents were not adversely affected by the traditional malting technology, except for phosphorus in NB1 and magnesium in NB3. Overall, traditional malting technology is effective at reducing trypsin inhibitors and oxalates, and improving protein digestibility and iron bioavailability.