Effect of Defatting and Extraction Solvent on the Antioxidant and Pancreatic Lipase Inhibitory Activities of Extracts from Hermetia illucens and Tenebrio molitor

Abstract

The production of specific insect extracts with bioactive properties for human health is an emerging and innovative field for the edible insects industry, but there are unexplored extraction factors that might modulate the bioactivity of the extracts. Ultrasound-assisted extracts from T. molitor and H. illucens were produced. Effects of defatting pre-treatment and extraction solvent were evaluated on extraction yield, antioxidant activity and pancreatic lipase inhibitory effect. Chemical characterisation of defatted extracts from H. illucens was performed by GC-MS-FID. Non-defatted extracts showed higher extraction yields. Defatted extracts had similar extraction yields (around 3%). Defatted extracts had higher antioxidant activity, T. molitor being stronger than H. illucens. Antioxidant activity of T. molitor methanol extract was higher than the rest of solvents. Aqueous ethanol improved the antioxidant activity of H. illucens extracts. All extracts inhibited lipase, but no significant effect of defatting and solvent was observed for T. molitor. A significant higher inhibitory activity was observed for H. illucens, the strongest being defatted 100% and 70% ethanol H. illucens extracts. H. illucens extracts contained free amino acids and disaccharides, together with minor fractions of lipids, sterols and organic acids. These results evidence the potential of extracts obtained from edible insects as antioxidants and inhibitors of the pancreatic lipase, a simultaneous multibioactivity that might be favoured by the defatting pre-treatment of the samples and the solvent of extraction.