OPPORTUNITIES AND LIMITATIONS OF OBTAINING SUSTAINABLE NUTRACEUTICALS – THE CASE OF TOMATO PROCESSING WASTE

Dubravka Vitali Čepo1*, Nikolina Golub1, Emerik Galić1, Kristina Radić1, Jasna Jablan1, Tomislav Vinković2
1University of Zagreb, Faculty of Pharmacy and Biochemistry, Ante Kovačića 1, 10000 Zagreb, Croatia
2Josip Juraj Strossmayer University of Osijek, Faculty of Agrobiotechnical Sciences, Vladimira Preloga 1, 31000 Osijek, Croatia

Introduction
The global demand for sustainable and health-promoting products has driven significant interest in the utilization of food waste as a source of nutraceuticals. Tomatoes, widely processed into different food products, generate substantial amounts of waste which is abundant in valuable bioactives such as lycopene, polyphenols, and dietary fibers. T This offers an attractive avenue for sustainable nutraceutical development that fits into the paradigm of circular economy. However, it but also comes with different technical, economic, regulatory, and environmental challenges such as heterogenicity of raw material, contamination issues, impact of processing and storage, sustainability and cost efficiency of existing extraction procedures, scale up challenges etc. In this work we investigated sanitary safety of tomato pomace and investigated the importance of processing conditions on the content of its major target compounds – polyphenols, pectins and carotenoids.
Materials and Methods
Tomato pomace was obtained by processing a mixture of autochthonous Croatian tomato varieties into tomato sauce. Assessment of sanitary safety included determination of heavy metal (by AAS) and pesticide residues (by GC-MS). The impact of drying conditions (air-drying at 70 °C vs. lyophilization) and the degree of milling on the content of total antioxidants (UV-VIS), polyphenols, carotenoids (UV-VIS, HPLC) and pectins (gravimetric method) in whole tomato pomace, tomato skin and seeds were also investigated.
Results
The sanitary safety of tomato pomace samples was satisfactory. Tomato pomace contained high content of pectins that were not significantly affected by pre-extraction processing of raw material. Polyphenols were shown to be the major contributors to antioxidant capacity of tomato pomace and were significantly affected by the type of drying applied. Carotenoid content (β-carotene and lycopene) was also primarily affected by drying and less by degree of milling and it was significantly higher in tomato skin (in comparison to seeds).
Conclusions
Considering its sanitary safety and chemical composition, tomato pomace can be considered valuable source of bioactive compounds. The amount of polyphenols and carotenoids can be significantly affected by the drying conditions and, to a lesser extent, degree of milling, and varies depending on the ratio of tomato skin and seeds in the pomace.