Defatting cricket flour: a key strategy to improve stability in insect-based feed

United Nations’ projections estimate that by 2080, the global population will reach 10.4 billion, resulting in a substantial increase in the demand for food and protein sources. This growing need has directed attention towards the potential of edible insects as alternative protein sources. Recently, the use of insect meal and insect fat in animal feed has gained attention due to their potential nutritional and sustainability benefits. Insect-based ingredients, such as those derived from crickets (Acheta domesticus), offer high-quality protein and essential fatty acids while also contributing to a reduction in the environmental footprint of traditional animal feed production. 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 flour and insect-based animal feed. The aim of the present work was to assess the oxidative stability of undefatted (UD) 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), total fatty acids (FA) and total sterols 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 UD samples, while hydrocarbons (24.9-75.0%) and carboxylic acids were more abundant (14.2-47.9%) in D samples. In UD 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, 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 UD at all sampling times. On the other hand, the only common oxidation maker detected in both UD and D was acetic acid, which could derive from the oxidation of aldehydes and ketones 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 UD-T0 and UD-T30, respectively. Regarding FA composition of UD samples, it was mainly represented by PUFA (40.4%), followed by SFA (32%) and MUFA (27.1%). As observed for VOCs, PUFA significantly decreased (~11%) during ASL, especially C18:2 cis-9,12 (~10.8%). Although the sterol content does not seem to decrease during the ASL, small amounts of SOPs were formed. These preliminary results supply valuable information to support research and formulation of insect-based animal feed, providing an important basis for identifying appropriate preparation and preservation strategies to reduce lipid oxidation in this ingredient, so as to improve the nutritional and sensory quality of insect-based products.