Antioxidant browning reaction products

Yamaguchi, N. Koyama, Y. Fujimaki, M. Fractionation of antioxidative activity of browning reaction products between D-xylose and glycine. Prog. Food Nutr. Sci. 1981, 5, 429-39. 

K.-G. Lee and T. Shibamoto, Toxicology and antioxidant activities of non-enzymic browning reaction products Review, Food Rev. Int., 2002, 18, 151-175. 

Carbonyl-amine reactions, such as those between lactose and milk proteins, have been reported to produce potent antioxidants (Dugan, 1980 Eichner, 1980 Ericksson, 1982). Browning reaction products can stabilize milk fat considerably (Wyatt and Day, 1965). However, it is important to note that browning reaction products may exert adverse nutritional and toxicological effects (O Brien and Morrissey, 1989). 

Many studies of the effect of thermal processing used such a wide variety of non-specific methods to evaluate antioxidant activity that the results can be confusing and difficult to interpret (Tables 11.6 and 11.7). Because most natural antioxidants and those derived from browning reaction products are multifunctional, a reliable antioxidant protocol requires the measurement of... 

Table 11.7. Antioxidant activity of browning reaction products in foods and beverages...

More recent studies determined hexanal and other volatile compounds by headspace gas chromatography (HS-GC) to measure lipid oxidation in meat. Although hexanal data may sometimes be in agreement with the results of the non-specific TEA method, the sensitive HS-GC method is more desirable because it determines specific decomposition products of lipid hydroperoxides. The same factors that influence lipid oxidation in meat such as pH, metal catalysts and antioxidants also affect and confound the interpretation of the results of the colorimetric TEA method. The TEA method is, therefore, not recommended to determine oxidation of meat and other complex foods because the degree to which non-lipid oxidation and degradation products, including browning reaction products, contribute to the TEA color remains unclear. 

Kim, N.K. and Harris, N.D. Antioxidant effect of non-enzymatic browning reaction products on linoleic acid, in Trends in Food Science, pp. 19-23 (1989) (edited by A.H. Ghee), Singapore Institute of Food Science and Technology, Singapore. 

Kirigaya, N. Kato, H. Fujimaki, M. Studies on antioxidant activity of nonenzymic browning reaction products. Agric. Biol. Chem. 1968, 32, 287-290. 

Yamaguchi, N. Fujimaki, M. Studies on browning reaction products from reducing sugars and amino acids. Antioxidative activity of purified melanoidins and their comparison with those of legal antioxidants. Nippon Shokuhin Kogyo Gakkaishi 1974, 21, 6-12. 

The synergism exhibited by the ternary mixture of a-tocopherol, ascorbic acid and phospholipids has been shown to be due to the stabilization of a-tocopherol, on the basis of ESR studies with methyl linolenate oxidized at 90°C to detect the free radicals of a-tocopherol and ascorbic acid. Evidence was obtained by this technique for the formation of nitroxide radicals (R-N-0 ) in the presence of phosphatidylserine or phosphatidylethanolamine or soybean lecithin and oxidized methyl linolenate. However, as pointed out earlier (Section C), the synergistic activity of this ternary mixture may be derived from antioxidant products formed from the phospholipids at elevated temperatures by the Maillard browning reaction (Chapter 11). 

Maillard reaction is known to occur in foods and biological systems (Eriksson, 1981 Waller and Feather, 1983 Fujimaki et aL, 1986 Baynes et al, 1989 Finot, 1990 Finot et al, 1990 Labuza et aL, 1994 Lee and Kim, 1996 Ikan, 1996). Recently, food browning and its prevention (Friedman, 1996) and the thermal generation of Maillard aromas (Ho, 1996) have been reviewed. Therefore, this overview, will concentrate on application aspects of the Maillard reaction relating to the generation of flavor, antioxidant properties, desmutagenic effects, protein-polysaccharide conjugates and other major reaction products. 

Saccharides are highly reactive substances that are transformed into many different products, even without the participation of other reaction partners, during food storage and processing. The most common and important reactions of carbohydrates are their reactions with amino compounds that are known as non-enzymatic browning reactions, which also involve reactions of carbohydrates in the absence of amino compounds. Reactions of carbohydrates with amino compounds (proteins, amino acids) are the MaiUard reactions. The products of these reactions are important flavour-active compounds and are yellow, brown or black pigments in many foods and compounds with beneficial properties (e.g. antioxidants), but can also be substances with antinutritional or even toxic effects. 

---