Does defattening improve the oxidative stability of Acheta domesticus flour during accelerated shelf-life conditions?

United Nations’ projections foresee that the world population will reach 10.4 billion in 2080, leading to a significant increased demand for food and protein sources. For these reasons, attention has been addressed to the production of edible insects as alternative food sources. Recently, Regulation (EU) 2023/5 authorized domestic cricket (Acheta domesticus) flours to be placed on the European market as a novel food. However, cricket flour may contain about 10-30% of lipids with a high level of unsaturation, which make it prone to oxidation. Thus, defatting cricket flour could be a promising strategy to improve the stability and shelf-life of both flours and flour-based food products. The aim of the present work was to assess the oxidative stability of undefatted (TQ) and defatted (D) Acheta domesticus flours. The flour was defatted by using the Folch extraction method, while the oxidative stability was assessed by determining the profile of volatile organic compounds (VOCs) and the total fatty acids (TFA) composition during an accelerated shelf-life study (ASL, 45°C/30 days). Regarding VOCs, the most representative classes were hydrocarbons (28.0-36.2%) and ketones (22.6-25.8%) in TQ samples, and hydrocarbons (24.9-75.0%) and acids (14.2-47.9%) in D samples. In TQ flours, 5 oxidation markers were identified: 3-methyl-butanal (4.6-7.9%), 2-pentyl-furan (2.3-3.6%), 2-heptanone (5.5-7.7%) and 1-pentanol (1.0-1.1%). These compounds may arise from the oxidation of unsaturated fatty acids (UFA), especially from linoleic acid (C18:2 cis-9,12), and/or from the oxidation of some amino acids (e.g. leucine) via Strecker degradation. Regarding D samples, no furans or alcohols were detected, thus suggesting a lower oxidation extent compared to TQ at all sampling times. On the other hand, the only oxidation maker detected in both TQ and D was acetic acid, which could derive from the oxidation of aldehydes and ketones in the flour and/or by fragmentation of alkoxyl or hydroperoxyl radicals. However, the content of acetic acid in D-T0 and D-T30 was 7 and 10 times lower than in TQ-T0 and TQ-T30, respectively. Regarding TFA composition of TQ samples, it was mainly represented by polyunsaturated fatty acids (PUFA, 40.4%), followed by saturated (SFA, 32%) and monounsaturated fatty acids (MUFA, 27.1%). C18:2 cis-9,12, C18:1 cis-9 and C16:0 accounted for more than 80% of TFA in the TQ samples. As observed for VOCs, PUFA significantly decreased (~11%) during ASL, especially C18:2 cis-9,12 (~10.8%). These preliminary results supply valuable information to support research and formulation of new insect-based products, providing an important basis for identifying appropriate preparation and preservation strategies to reduce lipid oxidation in this food ingredient, so as to improve the nutritional and sensory quality of insect-based products.