Influence of Supercritical CO2 Extraction Conditions on the Physicochemical Properties, Oxidative Stability and Bioactivity of Omega-3-Enriched Tenebrio molitor Oil

This study investigated supercritical carbon dioxide (SC-CO2) extraction of omega-3 (ω-3)-enriched oil from Tenebrio molitor larvae reared on a flaxseed-supplemented diet, using Soxhlet extraction as a benchmark. Within the investigated conditions, oil yield increased significantly with increasing pressure when temperature and CO2 flow rate were held constant. Low-pressure extraction resulted in higher residual moisture and acid values and a lower refractive index, indicating greater hydrolytic deterioration. Oleic (47.70–50.20%) and linoleic (20.39–21.18%) acids predominated, while α-linolenic acid reached 3.01–4.23%. Consequently, the ω-6/ω-3 ratio ranged from 4.86 to 6.91, which is substantially lower than the values generally reported for T. molitor oil. Extraction conditions caused only minor changes in fatty acid composition and did not alter the characteristic triacylglycerol structure confirmed by ATR-FTIR. SC-CO2 extraction substantially enhanced the recovery of phenolic compounds compared with Soxhlet extraction, with TPC reaching 87 mg GAE kg−1 oil and DPPH antioxidant activity reaching 1.89 mmol TE kg−1 oil under the most favourable extraction conditions. Differences in phenolic and tocopherol contents among the oils suggested that their antioxidant activity resulted from the combined contributions of several antioxidant compounds rather than from a single class of bioactives. The predicted shelf life was 105.8 days. Neither extraction method produced oil capable of completely inhibiting Staphylococcus aureus or Escherichia coli. Overall, dietary enrichment combined with carefully selected SC-CO2 extraction conditions represents a promising strategy for producing solvent-free, omega-3-enriched T. molitor oil, although further stabilisation may be required.