Stable isotope ratio analysis for the characterisation of edible insects

Abstract

Entomophagy, or the act of eating insects, has been practiced since ancient times, but it started to gain more popularity, especially in Western countries, only recently. As sustainability is one of the current emerging themes, the inclusion of insects in our diet is a valid alternative that might help reduce the amount of water and land used for livestock and the associated emissions of greenhouse gasses. Moreover, insects are a source of protein, fibres, vitamins, minerals and fats. Edible insects are considered a novel food, for which no isotopic reference values are yet available. In the present work, samples of farmed edible insects (n=40) belonging to different orders (namely, Coleoptera, Hemiptera, Hymenoptera, Lepidoptera, Odonata and Orthoptera) and insect-based food items (n=4) for human consumption were analysed. The following isotopes, δ13C, δ15N, δ34S, δ18O and δ2H of the defatted samples, together with the δ13C of the fat, were investigated. The aim of the work was to provide the first reference isotopic ratios that can be used for future investigations in the food quality field. The variability of these parameters was dependent on the life stage and diet of insects, their geographical origin, and the addition of ingredients as seasoning.

Traceability of insects as feed: stable isotope ratio analysis of Hermetia illucens larvae and pre-pupae reared on different protein sources

“…The average δ 13 C values recorded for BSF in this study ranged between -18.8‰ (defatted BSFP reared on ED1) and -14.9‰ (fat matter of the BSFL fed on ED4) (Tables 6-7). These results lay in the upper part of the range described by Pianezze et al (2021) (from -31.2 up to -12.2‰, on defatted matter) studying the isotopic ratios of 35 different edible insect species. For the diets' formulation, it was not possible to find corn gluten (C4 plant) in the retail market, in place of which was used wheat gluten (C3 plant).…”

“…The biochemical bases of such isotope fractionation have been masterfully formulated by De Niro and Epstein (1978). However, in our case the situation was quite different from other studies found in literature (Pianezze et al, 2021), for this study describes variable carbon isotope fractionation between the animals' compartments with respect to the isotopic abundance of the diets. In this study, the main (if not the sole) source of lipids in the BSF diet was the corn oil, whose δ 13 C value was very stable at -16.3‰ and highly enriched with respect to C3 metabolism plant oils (e.g.…”

Characterization of Beef Coming from Different European Countries through Stable Isotope (H, C, N, and S) Ratio Analysis

“…The δ ( 13 C) of the fat and the protein fraction of meat are known to be correlated, as reported in the literature [ 30 , 31 , 32 ]. Nevertheless, to exclude the lack of additional information derived from the analysis of the δ ( 13 C) of the fat fraction, a subset of beef muscle samples was measured to assess this parameter.…”

Woman the hunter: The archaeological evidence

“…Other explanations for the isotopic evidence, such as smaller consumption of meat in a dried/cured form (Speth, 2017) or mushroom consumption (O'Regan, Lamb and Wilkinson, 2016), may explain Neanderthal trophic‐level values better but are less masculine‐sounding. In addition, the isotopic signature in bone for the consumption of other protein sources like insects are currently unknown (Pianezze et al., 2021). Henry and colleagues (2014) argue that Neanderthals were sophisticated gatherers of plant foods for nutrition and medicine and that this suggests specialized gathering roles—but they are careful to say that these are not necessarily women's roles.…”