36E-45 |
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M. RENITA and S. J. Schwartz. Dept. of Food Science and Technology, Ohio State Univ., 2015 Fyffe Ct., Columbus, OH 43221 Recent evidence has shown that thermal processing may increase isomerization of carotenoids such as β-carotene or lutein. The predominant form of these carotenoids in nature is the all trans configuration, while thermal processing may induce cis isomerization. The yellow tomato variety consists of higher amounts of four lycopene precursors: phytoene, phytofluene, ζ-carotene, and neurosporene, in which these carotenoids are prevalent in the cis form. The effects of thermal processing on isomerization reactions of these precursors have not been studied. The objective of this study is to determine the effects of thermal processing on carotenoid lycopene precursors. Yellow tomatoes were processed in cans at 100, 150, 200, and 250o F for 30, 60, and 90 min. Each can was extracted and analyzed using reversed phase C30 High Performance Liquid Chromatography coupled with a Photo Diode Array detector (HPLC-PDA). Temperature showed a significant correlation to the increase of isomerization for all carotenoids (P<0.01). Further processing at 200F and 250F was found to have a notable effect on isomerization (P<0.05). Processing time did not show any difference in isomerization for these precursors. However, only phytofluene behaved differently from the group and correlated significantly with the extent of processing time. We also observed that during mild heat treatments, these carotenoids tended to be more easily extracted from the thermally processed tomato matrix. However, these changes were not significant. Results of this study suggested that temperature affected isomerization of lycopene precursors, whereas processing time only increased isomerization to phytofluene. Further investigation will be required in order to determine the structures of these isomers, whether they were converted to trans or other cis configurations.
Session 36E, Fruit & Vegetable Products: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |