Tomato lipid oxidation

Visioli, F. et al.. Protective activity of tomato products on in vivo markers of lipid oxidation, Eur. J. Nutr, 42, 201, 2003. 

Hwang, E-S and PE Bowen. 2005a. Effects of lycopene and tomato paste extracts on DNA and lipid oxidation in LNCaP human prostate cells. BioFactors 23 97-105. 

The oxidation products of lipids include volatile aldehydes and acids. Therefore, lipids are one of the major sources of flavors in foods. For example, much of the desirable flavors of vegetables such as tomatoes, cucumbers, mushrooms, and peas (Ho and Chen, 1994) fresh fish (Hsieh and Kinsella, 1989), fish oil (Hu and Pan, 2000) and cooked shrimp (Kuo and Pan, 1991 Kuo et al., 1994), as well as many deep-fat fried foods such as French-fried potatoes (Salinas et al., 1994) and fried chicken (Shi and Ho, 1994), are contributed by lipid oxidation. LOX-catalyzed lipid oxidation produces secondary derivatives, e.g., tetradecatrienone, which is a key compound of shrimp (Kuo and Pan, 1991). The major difference between the flavors of chicken broth and beef broth is the abundance of 2,4-decadienal and y-dodeca-lactone in chicken broth (Shi and Ho, 1994). Both compounds are well-known lipid oxidation products. A total of 193 compounds has been reported in the flavor of chicken. Forty-one of them are lipid-derived aldehydes. 

F Boukobza, PJ Dunphy, AJ Taylor. Measurement of lipid oxidation-derived volatiles in fresh tomatoes. Postharvest Biol Technol 23 117-131, 2001. 

Agarwal, S. and Rao, A.V., Tomato lycopene and low density lipoprotein oxidation a human dietary intervention study. Lipids, 33, 981, 1998. 

Kim, H.S. and Lee, B.M., Protective effects of antioxidant supplementation on plasma lipid peroxidation in smokers, J. Toxicol. Environ. Health A, 63, 583, 2001. Gaziano, J.M. et al.. Supplementation with beta-carotene in vivo and in vitro does not inhibit low density lipoprotein oxidation. Atherosclerosis, 112, 187, 1995. Sutherland, W.H.F. et al.. Supplementation with tomato juice increases plasma lycopene but does not alter susceptibility to oxidation of low-density lipoproteins from renal transplant recipients, Clin. Nephrol, 52, 30, 1999. 

Tomato was reported to exert antioxidant activity in some studies (Vinson and others 1998 Kahkonen and others 1999), whereas it showed no antioxidant activity or even acted as a pro-oxidant in others (Gazzani and others 1998). The antioxidant effect of tomato is most probably due to synergism between several compounds and not due to lycopene content alone, as pure lycopene and several other carotenoids act as pro-oxidants in a lipid environment (Al-Saikhan and others 1995 Haila and others 1996). 

FIG. 12 Effect of dietary lycopene supplements on serum LDL oxidation (SS, spaghetti sauce TJ, tomato juice TO, tomato oleoresin). Bars with different letters are statistically different (p < 0.05). (Tomato lycopene and low density lipoprotein oxidation A human dietary intervention study. Reprinted from Lipids. 1988 33, pp. 981-984 by permission of AOCS Press.)... 

The majority of heterocyclic compounds are formed through thermal interactions of reducing sugars and amino acids, known as the Halliard reaction. Other thermal reactions such as hydrolytic and pyrolytic degradation of food components (e.g. sugars, amino acids, vitamins) and the oxidation of lipids also contribute to the formation of heterocyclic compounds responsible for the complex flavor of many foodstuffs. Heterocyclic compounds may also be formed enzymatically in vegetables (tomatoes, bell peppers, aspara-... 

The carotenoid activity during oxidation is strongly influenced by the oxygen pressure (PO2) of the experimental conditions. Kiokias and Oreopoulou have shown that certain natural carotenoid mixtures (paprika, bixin and tomato, and palm-oil preparations) inhibited the azo-initiated oxidation of sunflower oil-in-water emulsions (operated rapidly under low pOj) in terms of both primary and secondary oxidation products. However, other studies " concluded that carotenoids not only did not inhibit aerial lipid autoxidation (high PO2) but even exerted a prooxidant character, a phenomenon also observed at high carotenoid concentrations that could be due mainly to a more increased formation of carotene-peroxyl radicals, promoting the propagation of autoxidation. 

---