###### Abstract  
The aim of this study was to investigate an ultrasound-assisted method for the extraction of bioactive compounds from tomato pomace. This method was based on a simple ultrasound treatment using different solvents (e.g., acetone, ethanol, ethyl acetate) as extraction media. Three different variables were chosen to determine their influence on extraction efficiency, such as solvent/liquid ratio (0.1:25 g/mL, 0.2:25 g/mL, 0.3:25 g/mL), temperature (30 \({}^{\circ}\)C, 40 \({}^{\circ}\)C, 50 \({}^{\circ}\)C), and time (2 h, 6 h, 10 h); the variables were selected through Box-Behnken design experiments. These parameters were optimized to achieve the highest yield, and the results showed that acetone was the best extraction solvent for lycopene (3.36 mg/100 g), total phenolic content (TPC) (31.15 QUE mg/L), and total flavone content (TFC) (66.80 GAE mg/L), while DPPH activity (82.94%) was the highest when ethanol was used as the solvent. Regarding the solvent/liquid ratio, the best results were obtained at a ratio of 0.1:25. Temperature influenced the extraction, with the best results observed at 50 \({}^{\circ}\)C for lycopene, DPPH, and polyphenols, while the flavonoids were better extracted at 30 \({}^{\circ}\)C. Time played an important role as well, with the best extractions observed at 10 h. The results indicated that ultrasound-assisted extraction was suitable for extracting bioactive compounds from tomato pomace. tomatoes; ultrasound; extraction; bioactive compounds; carotenoids +
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The chemical compositions of these skins and seeds vary significantly. Notably, pomace contains valuable components such as lycopene, dietary fibers, proteins, and oil. The main valuable components present in seeds and skins differ considerably. Skins are rich in dietary fibers, lycopene, and phenols, while seeds mainly consist of oil and proteins. In tomato skins, potassium is notably abundant (approximately 1.1 g/100 g), while sodium levels are relatively lower (70 mg/100 g). This low Na/K ratio suggests that tomato skins could potentially serve as agents for mitigating cardiovascular diseases [6]. It was noted that both tomato seeds and skins contain approximately 27% lipids, which were extracted using hexane. The most predominant fatty acid found was oleic acid, followed by palmitic acid. Additionally, a high protein content of around 40% was observed post-hexane extraction, with notable amounts of threonine and lysine. The extracted flour also exhibited significant levels of major elements such as Mg, K, Na, and Ca, as well as trace elements including Fe, Mn, Zn, and Cu. Furthermore, acetone extraction resulted in a highly intense coloration, primarily attributed to lycopene, with a total yield of approximately 12 mg/100 g [7]. The protein content here was 11%, containing lysine, valine, and leucine, as well as Ca, K, Na, and Mg [7]. The extraction of compounds from the matrix is a crucial process for structural composition analysis or for their use in various fields. This procedure is influenced by a variety of factors, including matrix particle size, type of solution used, time, technique applied, and temperature [8]. There are various compound extraction methods for vegetable products. One extraction method uses solvents like ethanol, methanol, ethyl acetate, or hexane, among other solvents. Conventional solvents like methanol and hexane are recognized for their high extraction yield, but for environmental safety, ethanol is a safer alternative. Various extraction techniques can be used, such as mechanical agitation, ultrasounds, homogenization, Soxhet-type extraction, maceration, and supercritical fluid extraction [8; 9; 10] for the extraction of different compounds (e.g., caroten, phenols, flavones). The Box-Behnken design is adequate to identify the most significant variables involved in the extraction process of different compounds from the matrix.