Tomato (Solanum lycopersicum L.) processing main product (juice) and by-product (pomace) bioactivity potential measured as antioxidant activity and angiotensin-converting enzyme inhibition

Abstract

Bioactivity potential of tomato (Solanum lycopersicum L.) juice and pomace was explored by performing four different antioxidant in vitro assays and angiotensin-converting enzyme (ACE) inhibition assay on their lipophilic and hydrophilic extracts. The content of major phytochemicals responsible for bioactivity was determined using HPLC-DAD and HPLC/UV-PAD/ESI-MSn. Rutin was found in higher quantity in pomace, while juice was richer in caffeoyl-hexosides. Ferric ion reducing ability (FRAP) of both pomace extracts was significantly higher than those of juice, while juice hydrophilic extract showed higher nitric oxide radical scavenging capacity. Tomato carotenoids were shown to be more efficient superoxide anion scavengers than phenolic compounds which, in turn, showed higher activity in FRAP assay. ACE inhibitory activity of pomace hydrophilic extract was significantly higher than that of juice at extract concentration of 10 mg/mL. This gives the tomato pomace a new possible utilization for economic and eco-friendly tomato juice and paste production. Practical ApplicationsDuring industrial processing of tomato into juice, a by-product - tomato pomace is formed, consisting mainly of skin and seeds. Tomato pomace could be extracted consecutively with hexane and ethanol as environmentally preferable solvents, giving extracts which contain carotenoids and phenolic compounds. These extracts possess bioactivity potential and could be used as ingredients for value added food products.