Evaluation of tomato introgression lines diversified for peel color as a source of functional biocompounds and biomass for energy recovery

Aim of the work was to characterize the peels of novel tomato lines (with red, orange, pink, black-red, and darkred fruit) for the content of bioactive substances and for some parameters linked to no-food use. Chlorophyll, polyphenols, and carotenoid content, energy value, theoretical biochemical methane potential (TBMP) through stochiometric method were evaluated. The peel color mirrored a different content of the bioactive substances: the dark-red fruits showed a significant increase of the carotenoid content, while the peel of the black-red fruits had the highest values of polyphenols. The preferential accumulation of functional compounds influenced the values of the other parameters. The colored lines compared to the red-fruited control (C) contained less carbon and hydrogen mass fractions and, subsequently, a lower LHV. This, in turn, led to a substantial difference in the estimation of the TBMP. Interestingly, this production was higher in the highly pigmented line, which contained a gene present in some high-lycopene commercial varieties. A circular production model for exhaustive use of peel is proposed.