The nitrogen-to-protein conversion factor of two cricket species - Acheta domesticus and Gryllus bimaculatus

Authors

• Tiina Ritvanen Finnish Food Authority
• Helena Pastell Finnish Food Authority
• Annikki Welling Finnish Food Authority
• Marja Raatikainen Finnish Food Authority

DOI: https://doi.org/10.23986/afsci.89101

Keywords:

amino acids, insects, novel foods, protein analysis

Abstract

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.