Artisanal oil obtained from insects’ larvae (Speciomerus ruficornis): fatty acids composition, physicochemical, nutritional and antioxidant properties for application in food

Abstract

A novel insect oil (SRO) from Speciomerus ruficornis Germar larvae was obtained by artisanal non-solvent extraction and its physicochemical properties were investigated. The SRO presented low levels of acidity and peroxides, which is an indication of good quality and conservation standards. The composition of fatty acids showed major content of oleic (32.2%), lauric (21.3%), myristic (19.0%) and palmitic (17.6%) acids. The nutritional quality of its lipid fractions was evaluated through the atherogenicity (~ 3.1) and thrombogenicity (~ 2.2) indices, hypocholesterolemic/hypercholesterolemic (1.0) ratio, and calculated oxidability value (~ 0.82). SRO presented significant amounts of polyphenols, ~ 56 µg GAE mL−1 of oil, and a relevant antioxidant capacity, ~ 42 µg TE g−1 of oil, which could offer protection against oxidative agents. The FTIR spectra revealed high intensity bands ranging between 2924 and 2854 cm−1 and 1745 cm−1, related to the functional groups from long-branched fatty acids and triglycerides. The SRO presented great thermal behavior determined through thermogravimetric and differential scanning calorimetry analysis, which displayed peak temperature at ~ 388 °C and an endothermic peak around 10 °C related to crystallization of SFAs, respectively. The results of this study shows that SRO is an interesting solvent-free source of fatty acids with significant antioxidant capacity and good thermal behavior. Furthermore, different technologies to obtain SRO can be thought to increase its valuable application as a butter-like product in the food.