Thermal degradation of a neoxanthin-like xanthophyll to the potent aroma compound β–damascenone

AGFD 76

Yair Bezman, besman@agri.huji.ac.il1, Itzhak Bilkis, bilkis@agri.huji.ac.il1, Peter Winterhalter, p.winterhalter@tu-bs.de2, Peter Fleischmann, pfleisch@pop.tu-bs.de2, Russell L. Rouseff, rrouseff@.ufl.edu3, and Michael Naim, naim@agri.huji.ac.il1. (1) Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, PO Box 12, Rehovot 76-100, Israel, (2) Food Chemistry, Technical University of Braunschweig, Schleinitzstrasse 20, Braunschweig, 38106, Germany, (3) Citrus Research and Education Center, University of Florida, IFAS, 700 Experiment Station Rd., Lake Alfred, FL 33850
β–Damascenone, a cooked apple-like flavor, is formed during food processing, apparently not only by glycoside hydrolysis. Using GC-O and GC-MS, we show the non-enzymatic formation of β–damascenone from neoxanthin or one of its derivatives. The neoxanthin-like carotenoid was extracted from grass or spinach and separated on an alumina column. β–Damascenone formation was pH- and temperature-dependent occurring over two phases. The first was incubation with peroxyacetic acid at 60oC for 90 min, and the second was incubation at above 90oC for 20 min. Only traces of β–damascenone were formed when only one of the two phases was applied. About 40 ppb β–damascenone were produced from 0.5 mM carotenoid under optimal conditions. We hypothesize that during Phase 1, the C9-C10 double bond of xanthophyll undergoes direct oxidation, leading to an epoxide. Above 90oC (Phase 2), the C9-C10 bond is thermolysed and via allenic triol is converted to β–damascenone, under mildly acid conditions.
 

Sci-Mix
8:00 PM-10:00 PM, Monday, 14 March 2005 Convention Center -- Sails Pavilion, Sci-Mix

Division of Agricultural & Food Chemistry

The 229th ACS National Meeting, in San Diego, CA, March 13-17, 2005