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S. TIZIANI, S. J. Schwartz, and Y. Vodovotz. Dept. of Food Science & Technology, Ohio State Univ., 2015 Fyffe Ct., 110 Parker Food Science Bldg., Columbus, OH 43210-1007 A positive relationship between the consumption of tomato and tomato-based products and decreased risk of chronic diseases is largely documented. The beneficial effects on human health are in part attributed to antioxidant activity of carotenoids and as such methods to characterize these compounds are needed. The objective of this study was to determine the most efficient extraction method for NMR characterization of carotenoid from juice. Two different extractions were compared to analyze the carotenoid profile in tomato juice samples. The first method entailed the extraction of the pulp with 1:1 acetone/hexane followed by drying and further dissolution in CDCl3 prior to NMR analysis. In the second method, hydrophobic compounds were extracted directly and rapidly by CDCl3. Extraction parameters were evaluated by measuring the absorbance in the wavelength range 200 to 800 nm by UV-Visible spectrophotometer. One- and two dimensional nuclear magnetic resonance (NMR) experiments (COSY, TOCSY, HSQC, HMBC, DOSY) using a Bruker 800MHz spectrometer were performed and results were compared to data obtained by reverse-phase HPLC-PDA system. UV-Visible spectrophotometric data determined the most efficient agitation time of rapid extraction for NMR analysis was 5 minutes. Trans-lycopene, 15-15' cis-phytoene and others minor cis-lycopene isomers were identified by NMR and confirmed by HPLC analysis. The comparison of NMR spectra obtained by two carotenoid extractions revealed less risk of cross contamination and isomerization by application of rapid extraction. This work demonstrates treatment with CDCl3 is a rapid and gentle means of extracting carotenoids for NMR analysis. Additionally, appropriate NMR methods can serve as an excellent means to rapidly characterize complex carotenoid mixtures in tomato juice with minimal purification procedures.
Session 83, Food Chemistry: Antioxidant and bioactive agents
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |