Oils of insects and larvae consumed in Africa: potential sources of polyunsaturated fatty acids

The objective of this paper is to present the beneficial aspects of some insects consumed in sub-Saharan Africa, based on examples of insects consumed in Cameroon, to present their potential as sources of lipids and essential fatty acids. In Africa, termites, larvae of raphia weevil, caterpillars, crickets, bees, maggots, butterflies, weevil, etc. are significant sources of food. These insects belong mainly to the orders of : Isoptera, Orthoptera, Dictyoptera, Coleoptera, Hymenoptera, Lepidoptera and Diptera. Depending on the species, insects are rich in proteins, minerals (K, Ca, Mg, Zn, P, Fe) and/or vitamins (thiamine/B1, riboflavine/B2, pyridoxine/B6, acid pantothenic, niacin). The composition of oils extracted from the following six insects consumed in Cameroon was investigated : larvaes of raphia weevil (Rhynchophorus phoenicis), crickets (Homorocoryphus nitidulus), grasshopper (Zonocerus variegates), termites (Macrotermes sp.), a variety of caterpillars (Imbrasia sp.) and an unidentified caterpillar from the forest (UI carterpillar). The extraction yields of oil were 53.75%, 67.25%, 9.12%, 49.35%, 24.44% and 20.17% respectively for raphia weevil larvae, crickets, devastating crickets, termites, Imbrasia and UI caterpillar. The oil from raphia weevil mainly contains 37.60% of palmitoleic acid and 45.46% of linoleic acid. The oil from crickets is principally made up of palmitoleic acid (27.59%), linoleic acid (45.63%) and α-linolenic acid (16.19%). The oil from grasshoppers is composed of palmitoleic acid (23.83%), oleic acid (10.71%), linoleic acid (21.07%), α-linolenic acid (14.76%) and γ-linolenic acid (22.54%). The main components of termite oil are : palmitic acid (30.47%), oleic acid (47.52%) and linoleic acid (8.79%). Palmitic acid (36.08%) and linolenic acid (38.01%) are the two dominant fatty acids of Imbrasia oil. As Imbrasia oil, UI caterpillar oil is composed of palmitic acid (30.80%) and linolenic acid (41.79%). Stearic acid (7.04%), oleic acid (8.56%) and linoleic acid (6.59%) are also present. These results show that these insects are considerable sources of fat. Their oils are rich in polyunsaturated fatty acids, of which essential fatty acids are linoleic and linolenic acids. The ratio PUFA/SFA, in the majority of cases is higher than 0.8, associated with desirable levels of cholesterol.