Researchers from Germany reported on the effect of tomato processing on contents of carotenoids and vitamin E.
"The aim of this study was to investigate the effect of different types of tomato processing on contents of lycopene, beta-carotene and alpha-tocopherol," V. Bohm and colleagues wrote in the Journal of Agricultural and Food Chemistry.
The authors noted, "Samples of tomato sauce, tomato soup, baked tomato slices, and tomato juice were taken at different times of heating, respectively, after each step of production. HPLC was used to analyze contents of carotenoids and vitamin E."
"Due to the loss of water during thermal processing, contents of lycopene, beta-carotene and alpha-tocopherol on a wet-weight basis increased."
According to the researchers, "On a dry-weight basis, contents of lycopene increased or decreased depending on the origin of the tomatoes used, whereas the beta-carotene contents decreased or were quite stable.
"In contrast to lycopene, beta-carotene isomerized due to thermal processing. The alpha-tocopherol contents significantly rose during short-term heating."
"The increase was not caused by release of alpha-tocopherol from the seeds containing predominantly gamma-tocopherol and accounting for 2% of total alpha-tocopherol content only," Bohm and coauthors concluded.
Bohm and colleagues published their study in the Journal of Agricultural and Food Chemistry (Changes in contents of carotenoids and vitamin E during tomato processing. J Agr Food Chem, 2004;52(23):7005-7010).
For additional information, contact V. Bohm, University Jena, Institute Nutrition, Jena, Germany.