Extraction and Analysis of Tomato Seed Oil

Tomato seeds represent a very large waste by-product from the processing of tomatoes into products such as tomato juice, sauce and paste. One potential use for these seeds is as a source of vegetable oil. This research investigated the oil content of tomato seeds using several extraction techniques as well as an examination of the oil extracts to determine the composition of the minor constituents such as phytosterol and antioxidant composition. The oxygen radical absorbance capacity (ORAC) of the tomato seed oils were also measured and correlated with antioxidant contents. This research demonstrated that tomato seed oil yield was highest using hot ethanol and followed by hot hexane and finally SC-CO2. The SC-CO2 treatment, however, had the highest total phytosterol content as well as highest individual phytosterol content. Sitosterol, cycloartanol, and stigmasterol were the most abundant phytosterols present in the extracts. The highest concentrations of antioxidants were found in the hexane extract. The most abundant antioxidants found in the tomato seed oils were all-trans-lycopene, cis-3-lycopene and beta-carotene. ORAC was highest for the hexane extract. Oil yield was inversely proportional to both alpha-tocopherol and gamma-tocopherol content and positively correlated with cis-3-lycopene content. ORAC values were positively correlated with only all-trans-lycopene and cis-3-lycopene demonstrating their role as antioxidants in the tomato seed oil.