Abstract:
Subject description: Edible insects represent an interesting alternative source of proteins and
lipids for human and animal consumption and have the potential to play a significant role in a circular
economy to meet current societal challenges. There is growing interest in the use of insects in the
manufacture of biomaterials and the valorization of secondary waste products.
Objectives: The potential of locust (Locusta migratoria) oil, adapted to intensive breeding using
by-products as feed, for incorporation as an ingredient in cosmetic formulations is investigated.
Methods: Locusts are mass-reared under controlled conditions. Firstly, techniques for obtaining
good oil extraction yields from dried locust biomass were tested. Extraction using hexane as a solvent
(soxhlet) and traditional pressing. Fatty acid composition (%) and profile (%) and the major groups of
fatty acids of the migratory locust were determined (gas chromatography-mass spectrometry (GC-MS)).
For antioxidant capacity, two different methodologies were used (DPPH, FRAP), and agar diffusion
tests were performed for antibacterial activity.
Results and discussion: Migratory locust is rich in lipids (≈33% of dry weight), and traditional
pressing was found to be the best system for maximizing oil yield (26.90g/100g vs. 24.75g/100g for
hexane). The most abundant saturated fatty acid was palmitic acid, 16:0 (30.5%) followed by stearic
acid, 18:0 (9.3%TFA), while oleic acid, C18:1n9c (40.53%), was the main monounsaturated fatty acid,
and linolenic acid, C18:3n3 (13.7%) was the most abundant polyunsaturated fatty acid. Unsaturated
fatty acids (UFAs) make up 59% of TFA. MUFA are the most predominant fatty acids in locust tissues,
accounting for 41.2% of TFA, followed by SFA, which make up 41% of TFAs, and PUFA, which make
up 17.8% of TFA. The proportion of saturated/unsaturated fatty acids was (0.7). Omega-6 content was
(11.5mg/g) and omega-3 (24.8mg/g), representing (5.6% TFA) and (12.1% TFA). The N-3/N-6 ratio
was 2.2. Regarding antioxidant activity, Locusta migratoria showed values of 2.03, and 4.93 mg TE/g
of oil for DPPH and FRAP tests. Interestingly, agar diffusion tests demonstrated the sensitivity of Gram
positive Bacillus subtilis and Staphylococcus aureus to the oil, while the growth of Gram-negative
Pseudomonas aeruginosa and Escherichia coli was unaffected. This study confirms that fat and other
active compounds in pressed oil could be effective antimicrobials against bacteria.
Conclusion: The fatty acid profile indicates a high proportion of unsaturated fatty acids, and the
antioxidant and antibacterial activity of pressed Locusta migratoria oil is promising for use in cosmetic
applications
