Impact of heat processing on the nutritional content of Gryllus bimaculatus (black cricket)

Insects are increasingly suggested as a potential novel solution to global nutrition challenges. However, limited research is available on what impact varied rearing and processing methods ultimately have on the nutritional content of edible insects. This trial examines the impact of six distinct diets, some based on bio-waste, on the nutritional content of the commonly consumed cricket, Gryllus bimaculatus. Results showed a significant impact of diet on the protein, micronutrient and fatty acid content of crickets. However, the majority of these relationships were not distinctly linear; in general, an increase in a certain area in the diet did not equate to the same increase in the crickets. The only nutritional element with a direct dietary relationship was α-linolenic acid, which increased as dietary content did. Following on from this the effect of various levels of heat processing on subsequent nutritional profile was studied. Results showed that different temperatures, from freeze drying up to 120℃ had no significant impact on protein or micronutrient content. However, the fatty acid content was significantly impacted by higher temperature processing. Freeze-drying crickets conserved significantly more of the longer chained polyunsaturated fatty acids than drying at 120℃. It is evident from ongoing research that insects hold potential as a source of essential nutrients and fatty acids, but when reared on low-quality feed and processed at high temperatures they are unlikely to be of any more nutritional benefit than foods presently used in nutritional interventions.