Bioconversion of orange pomace using Hermetia illucens larvae: development and nutritional composition of the larvae

Abstract

Oranges, a popular fruit, generate large amounts of waste, with half discarded as pomace after juice extraction, contributing to 110–120 million tons of citrus waste annually, and posing environmental challenges, especially regarding soil and water pollution. Therefore, this study evaluates bioconversion using larvae of Hermetia illucens (BSFL) fed with orange pomace, analyzing the effectiveness of the process and the resulting larvae's nutritional quality. Preliminary tests showed that pure orange pomace does not provide the necessary nutritional support for BSFL development. Thus, BSFL was fed with pomace supplemented with farinaceous at different concentrations: LA25 (25% pomace, 75% farinaceous residue), LA50 (50% pomace, 50% farinaceous residue), LA75 (75% pomace, 25% farinaceous residue), and LA0 (100% farinaceous residue). Larval performance, bioconversion development, and BSFL nutritional quality were evaluated. Results showed that BSFL can effectively convert orange pomace, utilize its nutrients, and reduce its pollutant potential. Overall, using only pure orange pomace did not support larval growth. However, increasing levels of farinaceous residue altered development, bioconversion parameters, and BSFL nutritional quality (p≤0.05). It was observed that 25% of the farinaceous residue (LA75) significantly improved BSFL's overall performance (p≤0.05), also enhancing the valorization of this residue concerning all evaluated parameters.