The Kjeldahl method is the most utilized method for total protein content analysis in food. Using the universal nitrogen-to-protein conversion factor of 6.25, the protein content of insects is likely to be overestimated due to their chitin content. We have calculated nitrogen-to-protein conversion factors for two crickets, house cricket (Acheta domesticus) and field cricket (Gryllus bimaculatus), which are used for food and feed in Europe. By analyzing their nitrogen and amino acid content we were able to show that a conversion factor of 5.09 could be used for house cricket and 5.00 for field cricket in protein content calculation. Based on these results with a reservation about slight variation in farming conditions, we suggest a nitrogen conversion factor of 5.0 for both crickets.

The interest in eating insects has grown in Western countries. Insects are on the market in some European countries due to the reinterpretation of EU legislation. In this study, house crickets (Acheta domesticus) were reared with two homemade and one commercial feed with different chemical compositions. Commercial chicken feed, which contained the highest levels of protein and minerals, produced the biggest and the most protein- and mineral-containing crickets. The protein content varied between 50.2 and 64.2 g/100 g (dry weight, DW). The examination of the amino acid profiles showed that the feed had a smaller effect on them than the amount of protein. Crickets, which received the most carbohydrate-rich feed, were highest in fat and lowest in protein. The fat content of all crickets was high (25.0–33.7 g/100 g, DW), and an average fatty acid profile was 40% saturated fatty acids (SFAs), 31% monounsaturated fatty acids (MUFAs), and 27% polyunsaturated fatty acids (PUFAs). A cricket’s diet has a significant effect on its composition.

SEDIMENTS, SEC 4 • SEDIMENT-ECOLOGY INTERACTIONS • RESEARCH

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