Influence of amino acid profile and secondary structure on nutritional and functional properties of Trichilia emetica and Trichilia dregeana protein concentrates

The high prevalence of protein energy malnutrition (PEM) is a major concern in Africa. This problem could be resolved through the nutritional use of locally available underutilized tree seeds such as those from Trichilia species. This study determined and compared the amino acid profile, functional properties, and secondary structure of the proteins from Trichilia emetica and Trichilia dregeana oilseeds. The results showed that the essential amino acid levels of the two Trichilia seed proteins were above the recommended Food and Agricultural Organisation standard for adults, with essential-to-total (E/T) amino acid ratios (T. dregeana 52.8%; T. emetica 53.4%) and chemical scores of 100% for both species, which were not significantly different (P > 0.05) from those of soy proteins (53.0% and 100%, respectively). The amino acid profile results indicated that Trichilia oilseeds can serve as candidates for addressing protein malnutrition in economically disadvantaged communities of sub-Saharan Africa. The secondary structure showed that the Trichilia oilseed proteins had significantly (P < 0.05) more beta-conformations compared to soybean proteins. Further, the functional properties suggested that Trichilia oilseed proteins can be used as ingredients in food and feed formulations due to their versatile functional properties.