Available free online at www.medjchem.com Mediterranean Journal of Chemistry 2016, 6(1), 686-691 *Corresponding author: Rim Driouich Received September 2 nd , 2016 Email address: dodrim@gmail.com Accepted October 21 st , 2016 DOI: http://dx.doi.org/10.13171/mjc61/0161107123915/driouich Published November 7 th , 2016 Valorization of Tomato Processing Waste for Lycopene Extraction Rim Driouich * , Olfa Bousselmi and Ameur Cherif Laboratory of Biotechnology and Valorization of Bio-Geo Resources BVBGR LR11ES31 Institut Supérieur de Biotechnologie de SidiThabet University of Manouba, BioTechPole Sidi Thabet 2020 Sidi Thabet, Ariana, Tunisia Abstract: Lycopene is one of the most powerful antioxidants and singlet oxygen quenching agents. It has been found to be of great medical importance with various anti cancer effects, cardiovascular diseases effective agent and with its ability to be an important carotenoid in preventive medicine. In Tunisia, we note a real consumption of tomato paste. With 28 production units for double and triple concentrated tomato, noting a significant production of waste (approximately 30000 Tonne/year) consisting of skins pulp and seeds, which could be an important source of lycopene. Our study is concerned with three solid-phase extraction process: assisted by ultrasonic, by microwave and by homogenizer heating at moderate temperature. Their efficiency for the extraction of lycopene contained in the tomato waste was elaborated. The effect of the main process variables (including solvent polarity, solid-to-liquid ratio, temperature and time) on lycopene recovery have been investigated. The yield of the isolated lycopene was determined using UV-Visible spectrophotometry and UPLC-DAD quantification methods. Lycopene-rich extract was obtained from the dried and milled tomatoes waste using ethanol as a food grade extraction solvent and employing microwave assisted extraction process. The optimum conditions were 30 min total extraction time at 50°C temperature and 1bar pressure. The degradation of extracted lycopene through air oxidation and day light effect were also tested. Lycopene is stable when mixed with olive oil as a natural antioxidant. Up to 80% of lycopene degradated when exposed for one month to day light at 25°C. Keywords : Lycopene, tomatoes, extraction, microwave, plants waste valorization. Introduction By-products of fruits and vegetables processing represent a major disposal problem for the industry concerned, but they are also promising sources of compounds which may be used for various purposes in food, pharmaceutical and cosmetic industries 1-2 . Tomato (Lycopersiconesculentum) is, after potato, the second most consumed vegetable in the world and approximately 30% is consumed as processed products. Both fresh and processed tomato contain a high nutritional value, due to its content of different types of micronutrients: carotenoids (lycopene and β-carotene), vitamins (C and E), folates, and polyphenolic compounds (flavonoids and phenolic acids) 3-4 . The skin of tomatoes has been found to be richer sources of lycopene than the water insoluble fraction and the fibrous fraction 5 . However, when tomatoes are processed into products, 3-7% of their weight becomes waste 6-7 . Tomato waste, known as tomato pomace, contains a significant amount of the fruit peels, which has no commercial value and is currently disposed as a solid waste or used for animal feeding. Nevertheless, a careful examination of this material reveals that it is a rich source of important nutrients and phytochemicals that could provide a potential source of natural lycopene. Lycopene is an acyclic tetraterpenic hydrocarbon with 13 carbon–carbon double bonds, 11 of which are conjugated, which has attracted a great attention in recent years for its potential health benefits 8 . The high degree of conjugation makes this carotenoid one of the most potent natural antioxidants, with a singlet-oxygen quenching ability twice as high as that of β-carotene and ten times higher than that of α- tocopherol 9 . Moreover, its activity is synergistically enhanced by the presence of other tomato phytochemicals including β-carotene, phytoene and phytofluene 10 . These properties are thought to be responsible for the apparent inverse association between the consumption of lycopene-rich foods