Tomato processing waste (TPW) represents a valuable but underutilized by-product of the food industry with potential for valorization within bioeconomy models. This study investigated the chemical composition, antioxidant profile, and sanitary safety of TPW, analyzing the whole TPW; its fractions (peels and seeds) and oil are obtained from TPW seeds. All samples showed contaminant levels within regulatory limits, confirming their safety for further applications. Various drying methods (air-drying at 70 °C and at 50 °C, lyophilization and vacuum drying) and grinding intensities were evaluated to determine their impact on TPW bioactive compounds retention and organoleptic characteristics. TPW exhibited valuable nutritional properties, particularly high protein and dietary fiber content while TPW oil was characterized with high monounsaturated fatty acid content. Results demonstrated that drying method and particle size significantly influenced the yield of bioactive compound and organoleptic properties, with either lyophilization or vacuum drying and finer milling generally enhancing the recovery of polyphenols, β-carotene, and lycopene and improving color intensity. This research provides the first characterization of the TPW obtained from Croatian indigenous tomato varieties, establishing a scientific foundation for its sustainable valorization and, in broader terms, supporting circular economy objectives and contributing to more resource-efficient food systems.

This study investigated the recovery of β-carotene (BC) and lycopene (LYC) from tomato processing waste (TPW) using microwave-assisted extraction (MAE) with green solvents. Sunflower oil (SO), olive oil, limonene, and several deep eutectic solvents were initially screened, after which SO and a capric acid–lauric acid deep eutectic solvent (CLA; 2:1 molar ratio) were selected for further optimization. The optimized MAE conditions for SO were 217 W for 4 min, yielding 2.82 ± 0.24 mg/100 g dry TPW of BC and 3.57 ± 0.27 mg/100 g of LYC, with an energy consumption of 0.014 kWh. For CLA, the selected conditions were 1800 W for 13 min, which resulted in significantly higher recoveries of BC (5.29 ± 0.84 mg/100 g) and LYC (9.80 ± 1.77 mg/100 g), although the energy consumption was higher (0.390 kWh). Vibrational micro-milling reduced the median particle size from approximately 303 to 66.8 μm and improved carotenoid recovery when combined with SO; however, it decreased recovery in CLA under more intensive MAE conditions. Life-cycle assessment (LCA) comparing optimal MAE extraction to conventional solvent extraction and ultrasound-assisted extraction showed that the CLA-based MAE process provided the most favorable overall balance between carotenoid recovery and environmental performance. Therefore, CLA can be recommended as the most effective solvent for the MAE recovery of BC and LYC from TPW, although further validation at a pilot scale and an assessment of solvent recovery are required.