This contribution is a piece of work within a more comprehensive research program dedicated to a thorough exploitation of industrial tomato by-products, which should be technically feasible, economically convenient and environmentally friendly. In this respect, the proposed paper focuses three aspects of newer and broader interest: lycopene extraction, cutin separation and compost production. The investigated case study refers to the tomato industry in the Campania region (IT).
The lycopene extraction from peels is usually carried out by a solvent- or supercritical CO2-assisted operation; the separation of cutin is performed in two process steps: alkaline hydrolysis and acidification. The solid residual, after cutin separation, is proposed to be used as feedstock for composting, not alone, but mixed with other suitable biomass to adjust both the final moisture content and C/N ratio. To this end, two scenarios according to the “biorefinery cascade approach” were developed that differ in the extraction technology for lycopene, i.e., 1) an optimized organic solvent; 2) CO2 as a supercritical fluid. The proposed process block diagram takes into account the upstream separation of peels from seeds and the downstream composting of seeds and residual solids (i.e., after lycopene and cutin extraction) in both scenarios, which were set up and quantitatively evaluated, under both viewpoints of process feasibility and economic sustainability. The mass and energy balances were written for all the involved process steps; the balance equations and the mathematical calculations were implemented and solved in MS EXCEL®.