Nutritional Potential and Low Heavy Metals Content of Oryctes monoceros (Olivier, 1789) and Rhynchophorus phoenicis (Fabricius, 1801) Adults, Two Coleopteran Species Consumed in Togo

Oryctes monoceros (Olivier, 1789) (Scarabaeidae) and Rhynchophorus phoenicis (Fabricius, 1801) (Curculionidae) are two insects generally known as formidable pests of oil palms and coconuts trees. Although little known, different developmental stages of these insects are consumed. The aim of this study is to determine the composition of these adult Coleopteran species in order to promote their consumption as a strategy for enhancing food security. Chemical analyses were carried out on adults of both species. Samples of O. monoceros and R. phoenicis were collected in three localities in Togo. The ash, protein, vitamin, and lipid contents were determined according to the AOAC reference methods. The fiber contents were obtained by the method of Weende. The minerals and heavy metals were analyzed by atomic absorption spectrophotometry and colorimetry. Fatty acid composition was determined by gas chromatography. The results showed the average protein content ranges from 44.32 ± 0.83 to 45.89 ± 0.83%. The lipid level is between 15.06 ± 0.28% and 14.64 ± 0.54. Their lipids contain unsaturated fatty acids, notably oleic (40.84 ± 0.112 vs. 40.84 ± 0.11%), linoleic (4.49 ± 0.00 vs. 5.07 ± 0.02%), and α-linolenic (5.07 ± 0.02 vs. 6.35 ± 0.01%) acid. They are excellent sources of minerals and vitamins. They are also free of heavy metals. These species could, therefore, contribute to the nutritional balance of consumers. They deserve to be better promoted for human consumption, as they could make a significant contribution to the fight against malnutrition and constitute a novel food source.