18B-7 |
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R. M. GALICIA-CABRERA1, C. Saucedo-Veloz2, J. R. Verde-Calvo1, E. Ponce-Alquicira3, and I. Guerrero-Legarreta1. (1) Dept. de Biotecnología, Univ. Autónoma Metropolitana, Iztapalapa, Apartado Postal 55-535, Mexico D.F., 09340, Mexico, (2) Colegio de Posgraduados, Montecillo, Estado de México, Texcoco, Mexico, (3) Dept. de Biotecnología, Univ. Autónoma Metropolitana, Iztapalapa, Apartado Postal 55-535, Mexico D.F., 09340 Lycopene is an important micronutrient for human health; in addition of being a food coloring material, it prevents lipid oxidation by trapping free radicals. This pigment is also an effective singlet oxygen quencher, inhibiting photoxidation by reducing electron excitation by incident light. Exposure to oxidative stressors (high oxygen concentration, heat and light) promotes depletion of the chromophore. The objective of this work was to study the stability of lycopene extracted from tomatoes cv. Saladette into canola oil stored under autoxidation and photoxidation conditions, and its antioxidant effect on canola oil. Lycopene was extracted with an organic solvent system (hexane:acetone:ethanol) from scalded and non-scalded tomatoes and added to canola oil (9 and 11 ppm). The samples were stored for 30 days under light (4330 lux) to promote photoxidation, and at 4, 20 y 60oC in the dark to study autoxidation. Control was lycopene-free samples. Residual lycopene concentration was analyzed by HPLC; oil oxidation by peroxide values. Fifty eight percent lycopene was lost at 30 days of storage under 4330 lux, 57% when stored at 60oC and 24% when stored at 4oC, probably due to isomerization and oxidation. Lycopene in samples stored under light and 24oC prevented hydroperoxide formation, whereas the control had high peroxide values throughout the study time. The highest peroxide value and lycopene depletion was observed in samples stored at 60oC in the dark, as the oxidized pigment probably acted as prooxidant; final lycopene concentration under these conditions was 2.68%; 30% lycopene was retained in samples stored at 4oC in the dark; oil peroxide value under these conditions was 7.5 meq/kg. Due to the considerable surplus in Mexico's tomato production, this cultivar can be a source of added value-pigments and antioxidants in the formulation of colored oil products increasing the stability against oxidation, in addition to tomato direct consumption.
Session 18B, Food Chemistry: Antioxidant and bioactive agents
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |