Assessment of lycopene content of fresh tomatoes (Lycopersicon esculentum Mill.) and tomato products in the United Arab Emirates

This study evaluated the lycopene content in fifteen varieties of locally produced tomatoes and compared it with lycopene content in those imported from other countries. In addition, three brands of tomato paste, three brands of ketchup and three brands of tomato hot sauce were evaluated for lycopene content. The lycopene content of the fresh tomatoes was determined by spectrophotometry and HPLC methods. The lycopene content in different varieties of tomatoes produced in the UAE as analyzed by spectrophotometry and HPLC methods ranged from <0.05 to 5.82 mg/100 g, and from 0.01 to 4.90 mg/100 g respectively, whereas the lycopene content in the imported unknown tomato varieties ranged from 2.40 to 5.98 mg/100 g (spectrophotometry) and from 1.78 to 5.46 mg/100 g (HPLC). The analysis of variance using SPSS software indicated a highly significant (P <= 0.05) variation in the total lycopene content between the fifteen varieties tested. Similar variation was observed in the pH and conductivity of the samples; however, there was no evident relationship between lycopene content and the pH of the varieties investigated. Results indicate that tomatoes produced in the UAE, with some exceptions, are superior in lycopene content compared to those imported from Holland, Egypt, Jordan and Turkey. The data obtained from the two measurement methods were found to be quite similar, indicating that total lycopene can be measured with a large degree of accuracy by using a spectrophotometer at a specific wavelength and molar extinction coefficient. The lycopene content in some processed tomato products ranged from 4.57 to 14.48 mg/100 g (spectrophotometry) and from 4.13 to 13.82 mg/100 g (HPLC).