Chitin Analysis in Insect-Based Feed Ingredients and Mixed Feed: Development of a Cost-Effective and Practical Method

Insects are used as an alternative sustainable, protein-rich ingredient in fish, pet, pig and poultry diets. The significant difference between insect meals and common protein sources is the content of chitin. The nitrogen contained in chitin, which makes up 6.89% of the chitin mass, is detected as crude protein in the analysis and, therefore, deludes the crude protein content in a higher range. In this work, we developed a chitin analysis method that does not require expensive and specialized equipment within insect production and processing industries. The method is based on classical chemical methods such as crude fibre and nitrogen content, making it easily implementable within existing feed analysis. In the process of method validation, a recovery rate of over 95% for chitin in the presence of protein and a standard deviation of < 5% at concentrations as low as 2% was determined. Furthermore, determining chitin at a higher standard deviation of > 10% at concentrations as low as 2% is possible. The method was used to determine the chitin content in various products derived from insect breeding and processing. The chitin content was determined in four insect species (Hermetia Illucens; Tenebrio molitor; Acheta domesticus; Bombyx mori) and different developmental stages of the yellow mealworm (T. molitor), including larvae, pupae and beetles, as well as in commercial pet food. These results also allow for an estimation of the insect protein content, provided that the raw material is known.