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Renewable Resources from Insects: Exploitation, Properties, and Refining of Fat Obtained by Cold‐Pressing from Hermetia illucens (Black Soldier Fly) Larvae

Matthäus, Bertrand, Piofczyk, Thomas, Katz, Heinrich, Pudel, Frank
European journal of lipid science and technology 2019 v.121 no.7 pp. e1800376
Codex Alimentarius, Food and Agriculture Organization, Hermetia illucens, World Health Organization, adults, allergenicity, allergens, amino acid composition, campesterol, coconut oil, crystallization, dodecanoic acid, endothermy, fatty acid composition, food processing, heat production, hygiene, insects, larvae, lipid content, melting, myristic acid, oilseeds, oxidative stability, palmitic acid, plant fats, pressing, protein content, refining, renewable resources, seeds, sensory properties, thermal stability, tocopherols, tocotrienols, triacylglycerols, vegetable oil
Hermetia illucens (black soldier fly) larvae are dried and mechanically treated by an oil seed screw press to extract the fat. This leads to an accumulation of the protein in the press cake with a protein content of 42% dry base. The amino acid composition fulfills the scoring patterns of FAO/WHO for adults. The extracted fat fraction has an interesting fatty acid composition with lauric acid (48%), myristic acid (11%), and palmitic acid (16%) as predominant representatives, very similar to palm kernel fat and coconut fat. The content of tocopherols and tocotrienols is low (64.7 mg kg⁻¹) while the total amount of sterols (3557 mg kg⁻¹) is comparable or higher to commonly used vegetable fats and oils. The sterol composition is dominated by campesterol (889.7 mg kg⁻¹) and ß‐sitosterol (1866 mg kg⁻¹). The high content of Δ5‐avenasterol may result in a higher thermal stability during food processing. The triacylglycerol composition of the fat is determined by LaLaLa (27.6%), LaLaM (16.0%), and LaMM (15.1%) resulting in DSC thermograms very similar to palm kernel and coconut fat with comparable exothermic (8.98 and 3.57 °C) and endothermic (27.23 °C) peaks. This gives the oil a melting and crystallization behavior comparable to that of palm kernel fat and could therefore be used in similar food applications. Since insect fat is only consumable after refining, the current work also investigates the effect of refining on some physical and chemical parameters. After refining the quality of the fat is within the limits defined by the Codex Alimentarius for Named Vegetable Oils and Fats. Practical Application: An increasing demand for fat makes the search for alternative sources a real challenge. Therefore, insects like Hermetia illucens come more and more into the focus of interest. A high fat content of the dried larvae allows the production of a valuable fat, when the protein is enriched by pressing the dried larvae with a screw press. For the first time, it is shown that the fat could be a useful alternative for other commonly used fats with specific technological properties such as palm kernel and coconut fat that are in discussion due to environmental reasons. Especially, the melting and crystallization behavior of H. illucens larvae fat seems to allow a replacement of traditional fats. For hygiene reasons, to improve the sensory quality and to remove allergen protein residues from the oil a refining process of the resulting insect fat is required. A refining process results in a product that corresponds with the standard of edible fats and oils. In the present work, only the chemical quality parameters of the insect fat are investigated. Questions regarding hygiene status, allergenic potential, and sensory quality are still open. In the present study, the protein and fat obtained from larvae of H. illucens after enrichment of the protein content by pressing the dried larvae with a screw press is characterized regarding amino acid composition and the composition of fatty acids, tocopherols, sterols, and triacylglycerols. In addition the oxidative stability, the melting and crystallization behavior and the effect of refining of the fat is analyzed. The results are compared with conventional used fat such as palm kernel fat and coconut fat showing the suitability of H. illucens fat as substituent.