Extraction of Lipophilic Antioxidants from Native Tomato Using Green Technologies

Abstract

Research background. Tomato (Solanum lycopersicum L.) fruit is highly consumed worldwide and contains high levels of carotenoids and tocopherols, two powerful antioxidants. Native tomato genotypes are rarely used in large-scale commercialisation and industries but serve as a reservoir to diversify the species gene pool and can be employed to obtain functional compounds. Extraction methodologies are currently experimenting changes towards cleaner methodologies that are more efficient and environmentally friendly, including avoiding toxic or polluting solvents. Experimental approach. In this study, factorial and fractional factorial designs were used to evaluate the efficiency of digestive enzymes, sonication and green solvents to extract carotenoids and tocopherols from native tomatoes. Results and conclusions. Digestive enzymes and sonication increased the carotenoid content and the antioxidant activity of the obtained extracts when applied individually. However, when these treatments were applied together and in combination with green solvents (ethyl lactate and isopropyl acetate), the obtained extracts had the highest carotenoid and tocopherol contents as well as the maximal antioxidant activity, compared with non-combined treatments. Moreover, a correlation analysis suggested that antioxidant activity resulted from synergistic effects between several antioxidants rather than individual compounds. The tomato extracts were obtained through a relatively rapid extraction method (2 h) and maintained their functional activity. Novelty and scientific contribution. Tomato is one of the most studied fruits, and both the plant and its fruit have been the subject of numerous studies. Functional compound extraction, mainly through environmentally friendly methods, remains an attractive research field for the utilisation of native tomato fruit, enhancing its limited production and use or harnessing the large amount of industrial waste from commercial tomato processing. There are few reports where clean extraction methods are combined; even rarer are those where green solvents are also used. In this work, the combination of different clean extraction technologies improved the extraction of carotenoids and tocopherols and allowed to establish a more efficient process. We believe that these results will stimulate the use of clean technologies and make the native tomato more attractive to harvest for industrial processing or to extract carotenoids and tocopherols for supplements.