Dietary camelina and linseed cakes modulate fatty acid classes and sensory traits of yellow mealworm larvae

This study evaluated the effects of including 5% and 10% camelina and linseed cake in the diet of Tenebrio molitor L., on the fatty acid (FA) composition and sensory traits of dried larvae. Five isonitrogen and isoenergy diets were tested: a control diet (CON), a diet with 5% camelina cake (CAM 5), 10% camelina cake (CAM 10), 5% linseed cake (LIN 5), and 10% linseed cake (LIN 10). Larvae were fed the diets from the 4th to the 9th week of age, then euthanized by freezing at -60 °C and freeze-dried for FA quantification. A portion of larvae was microwave-dried to conduct consumer sensory evaluation. Visual, olfactory and overall acceptance was assessed by 141 employers or students of the University of Padova. Results showed that incorporating camelina and linseed cakes at both 5% and 10% increased the amount of polyunsaturated fatty acids (PUFA) of larvae (P = 0.0053) and reduced their n-6/n-3 ratio (P < 0.0001). In terms of visual, olfactory, and overall consumer acceptance, larvae from the CON group received the lowest ratings, while those from the LIN 10 group were rated most favourably by consumers (3.90 vs 5.42, respectively; P<0.0001). In conclusion, this study demonstrated that dietary inclusion of camelina and linseed cakes enhanced the PUFA content and improved sensory acceptance of yellow mealworm larvae. Notably, the improvement in the n-6/n-3 ratio was proportional to the level of oilseed cake supplementation, with the lowest and most favourable ratio of 4.43 achieved in the LIN 10 group.