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Insects as Food: Fatty Acid Profiles, Lipid Classes, and sn-2 Fatty Acid Distribution of Lepidoptera Larvae

Abstract:

The aim of this work is to assess the fatty acid (FA) profiles, the lipid classes, and the positional distribution of FA within the triacylglycerol (TAG) structure of the lipids extracted from Lepidoptera larvae, compared with Diptera and Coleoptera ones. The major essential FA in most species was α-linolenic acid (ALA), at 62.5 mol% of total FA in Caligo memnon. Oleic acid (OA) was found in high amounts in Galleria mellonella, at 44.8 mol% of total FA. The n-6/n-3 ratio was below 1 in 12 of the 15 species surveyed, reaching 14.8 in Oryctes nasicornis. As for lipid fractions, an increase in the amounts of stearic and linoleic acids in the phospholipids fraction was observed. Distribution of FA in the sn-2 position of TAG is assessed through enzymatic hydrolysis reaction. Bombyx mori larvae contain ALA at 49.1 mol% of total FA at the sn-2 position of TAG, while OA is the main FA in sn-2 position in G. mellonella (88.5 mol% of total FA). Overall, Lepidoptera larvae constitute a rich source of specifically located at the sn-2 position OA and ALA, and similar or better than current sources. Initial data on other insect orders also points in this direction. Practical Applications: The present study develops knowledge about the lipid classes of Lepidoptera larvae, as well as on their regiospecific FA profiles. The data from Lepidoptera species are compared to other ones obtained from samples belonging to Diptera and Coleoptera. Insects are rich in essential amino acids; therefore if they contain omega-3 and omega-9 FA, would be healthy alternatives to other commonly consumed animal foods, which tend to be rich in saturated and omega-6 FA. Therefore, it is necessary to check different species to know their FA profile, as well as both the structure of their TAG and their lipid classes. Lepidoptera larvae constitute an alternative source of OA- and ALA-rich oils, which can be devoted for food use, as well as for using in the food and pharmaceutical industries, with agronomic implications. The lipid classes and the regiospecific fatty acid profiles of several Lepidoptera larvae (Class Insecta) with different geographic origin and compared to that of Coleoptera and Diptera is achieved. Enzymatic hydrolysis reaction shows that oleic and α-linolenic acids are preferably located at the sn-2 position of triacylglycerols in most of the analyzed species. According to the results of this work, new functional oils extracted from various insect species can be obtained.