In this study, the bambara protein isolate (BPI) was digested with three proteases (alcalase, trypsin and pepsin), to produce bambara protein hydrolysates (BPHs). These hydrolysates were passed through ultrafiltration membranes to obtain peptide fractions of different sizes (<1, 1-3, 3-5 and 5-10 kDa). The hydrolysates and their peptide fractions were investigated for antioxidant activities. The membrane fractions showed that peptides with sizes <3 kDa had significantly (p < 0.05) reduced surface hydrophobicity when compared with peptides >3 kDa. This is in agreement with the result obtained for the ferric reducing power, metal chelating and hydroxyl radical scavenging activities where higher molecular weight peptides exhibited better activity (p < 0.05) when compared to low molecular weight peptide fractions. However, for all the hydrolysates, the low molecular weight peptides were more effective diphenyl-1-picrylhydrazyl (DPPH) radical scavengers but not superoxide radicals when compared to the bigger peptides. In comparison with glutathione (GSH), BPHs and their membrane fractions had better (p < 0.05) reducing power and ability to chelate metal ions except for the pepsin hydrolysate and its membrane fractions that did not show any metal chelating activity. However, the 5-10 kDa pepsin hydrolysate peptide fractions had greater (88%) hydroxyl scavenging activity than GSH, alcalase and trypsin hydrolysates (82%). These findings show the potential use of BPHs and their peptide fraction as antioxidants in reducing food spoilage or management of oxidative stress-related metabolic disorders.

Summary Functional properties of protein concentrates prepared from three bambara groundnut landraces using acid precipitation and salt solubilisation methods were evaluated. The protein content of bambara grains (26–27%) was similar for the three landraces. The acid precipitation gave a much higher yield of protein concentrates (52%), which were also high in protein (79%) compared to the salt solubilisation method (yield: 25%, protein content: 57%). Functional properties of proteins were more influenced by the methods of preparation rather than the landraces. Protein concentrate prepared by salt solubilisation method showed higher emulsifying (63–66%), foaming (53–57%), water (1.4–2.0 mg mL−1) and oil absorption properties (2.2–2.6 mg mL−1) than the acid‐precipitated concentrates (53–57%, 63–66%, 2.0–2.7 mg mL−1, 1.4–1.7 mg mL−1). The foaming capacity and stability of all the protein concentrates decreased with increasing pH from 3 to 8. Salt solubilisation may be the most appropriate method for the enhanced functionality and utilisation of bambara groundnuts’ protein concentrates.

SummaryMoringa oleifera is a nutrient rich plant that has the potential to combat malnutrition problems in Africa. This study aims to investigate the effect of fortification using Moringa oleifera flower powder on the sensory and proximate attributes of fermented yellow maize and millet blend (Ogi). The formulation was grouped into seven blends in ratio 100:0:0, 70:30:0, 70:25:5, 70:20:10, 70:15:15, 70:10:20, 70:5:25 for maize, millet and Moringa oleifera flower powder (MOFP) respectively. Moringa oleifera flower was air-dried for 5days, milled and sieved to obtained fine powder. The fine powder was mixed thoroughly with fermented maize and millet, wet milled and sieved. The proximate composition of fermented yellow maize and millet (Ogi) fortified with Moringa oleifera flower powder showed an increase in crude protein, crude fibre, ash and fat with increase in the levels of Moringa oleifera flower powder and decrease in carbohydrate and moisture content. Moisture, protein, fibre, fat, ash and carbohydrate contents varied in the range 7.92-9.74%, 10.46 _ 16.06%, 2.31-4.13%, 2.90-4.07%, 1.23-1.93% and 66.45-73.25% respectively. Sensory evaluation shows that blend 6 (20% MOFP) compared favourably with the control. Also, nutritional analysis shows that blend 6 is favourable as weaning food. Therefore, blend 6 formulation can be used as alternative to the weaning foods to improve the nutritional status of children and help to curb protein malnutrition.