Biotransformation of insect processing residues: Production of lactic acid bacterial biomass and associated partial removal of proteins from chitin.

[Display omitted] • Insect residues can be biotransformed by lactic acid bacteria without a carbon source. • Deproteinization of 29 % achieved after 120 h of incubation by L. brevis. • Lactic acid bacteria biomass increased by 2 log 10 CFU/mL in only 48 h. • Biotransformation led to the formation of peptides with antioxidant activity. Processing of edible insects typically involves fractionating into high-value food ingredients, which results in by-products containing chitin and insoluble proteins. This study examined the effectiveness of lactic acid bacteria (LAB) in removing proteins from chitin in insect processing residues. Lesser mealworm processing residues were biologically treated for 48 and 120 h using LAB strains without added carbon sources. Results showed partial deproteinization, up to 29 % with Levilactobacillus brevis after 120 h. Most LAB grew up to 2 log 10 colony-forming units/mL in the first 48 h. Confocal microscopy and Fourier-transform infrared spectra indicated that some protein remained attached to chitin. The molecular weight of solubilized proteins was affected by strain and time of incubation, with antioxidant activity increasing significantly after 120 h with Lacticaseibacillus paracasei. The biological treatment of insect processing streams can be a sustainable approach to producing high amounts of LAB biomass with subsequent protein solubilization and chitin release. [ABSTRACT FROM AUTHOR]