Physicochemical properties and ellagic acid accumulation in Tenebriomolitor larvae fed with pomegranate peel-enriched media

Abstract

Edible insects are a promising and sustainable food source for humans due to their low environmental footprint, high feed conversion ratio, and high protein content. Furthermore, the nutritional profile of the edible insects can be modified depending on the provided diet. The aim of this study was to evaluate the growth performance, proximate composition, and ellagic acid accumulation in Tenebriomolitor larvae fed on corn flour media enriched with pomegranate peel. Corn flour and pomegranate peel were mixed in a 1:1 ratio (w/w) (PCM) and 50 T.molitor larvae were added to each jar. After 12 days of rearing, the weight of T.molitor larvae fed on PCM and the control increased by 88.35% and 58.6%, respectively, compared to their initial values. An increase in carbohydrate, protein and ash contents, along with a decrease in lipid content, was observed in the control diet after 12 days of feeding compared to the initial larvae. Conversely, the PCM diet exhibited an increase in ash and carbohydrate contents and a decrease in lipid and protein contents after 12 days of feeding compared to the initial larvae. Total phenolic content (TPC) of T.molitor larvae did not significantly vary when fed with the control group, while it increased on the fourth and twelfth days for larvae fed with the PCM diet. The CUPRAC antioxidant activity of larvae also increased on the fourth day of feeding on the PCM diet. Ellagic acid was not detected in larvae fed with control and initially, it accumulated in T.molitor larvae fed with PCM after 8 and 12 days of rearing, with concentrations of 92.54 and 115.6 µg/g larvae, respectively. This study highlights the importance of diet in changing the phenolic profile of T.molitor larvae, which can be used as a functional food ingredient to obtain value-added products from agricultural wastes.