Stability browning reactions

J. J. Sheu and R. G. Bland. Drilling fluid with stabilized browning reaction anionic carbohydrate. Patent US 5110484,1992. 

Selected clay stabilizers are shown in Table 1-10. Thermal-treated carbohydrates are suitable as shale stabilizers [1609-1611]. They may be formed by heating an alkaline solution of the carbohydrate, and the browning reaction product may be reacted with a cationic base. The inversion of nonreducing sugars may be first effected on selected carbohydrates, with the inversion catalyzing the browning reaction. 

Microbial growth, enzymatic reactions, non-enzymatic browning (reaction between carbonyl and amino compounds), and lipid oxidation are the major deterioration mechanisms that limit the stability of low moisture (o intermediate moisture foods (o.6o < <0.85) and biological materials. 

Griffith, T. Johnson, J. A. Relation of the browning reaction to storage stability of sugar cookies. Cereal Chem. 1957, 34, 159-69 through ref. 90. 

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). 

The nature of the sugars in a nonenzymic browning reaction determines their reactivity. Reactivity is related to their conformational stability or to the amount of open-chain structure present in solution. Pentoses are more reactive than hexoses, and hexoses more than reducing disaccharides. Nonreducing disaccharides only react after hydrolysis has taken place. The order of reactivity of some of the aldohexoses is mannose is more reactive than galactose, which is more reactive than glucose. 

Maltitol has good thermal and chemical stability. When it is heated at temperatures above 200°C, decomposition begins (depending on time, temperature, and other prevailing conditions). Maltitol does not undergo browning reactions with amino acids, and absorbs atmospheric moistme only at relative humidities of 89% and above, at 20°C. 

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). 

A mixture of emulsifiers can improve the stability of colloid food systems by strengthening the film membrane and by interaction between emulsifiers at the interface. Combinations of oil-soluble and water-soluble surfactants (Spans and Tweens) are often used in food formulations to produce more stable oil-inwater emulsions. Mixtures of phospholipids and proteins in foods undergo complex interactions during various thermal processing that can either promote or retard oxidation. At elevated temperatures phospholipids can produce antioxidant substances by the browning reaction, and proteins can denature to release reducing sulfhydryl groups that increase the oxidative stability of heated foods (e.g. evaporated milk). 

Cyclodextrins (a-, p-, y-) are widely used in the food industry as food additives, for stabilization of flavors, for elimination of undesired tastes or other undesired compounds such as cholesterol, and to avoid microbiological contamination and browning reactions. The characteristics of the cyclodextrins at the industrial level and their main properties from a technological point of view, such as solubility and their capabihty to form inclusion complexes, are important in the use of these compounds in the food industry [104],... 

However, contrasting results have been reported for the pressed canola oil obtained from heat treated seeds (Prior et al, 1991a). As the temperature of heat treatment of seed prior to pressing increased the content of non-acylglycerol components (from browning reactions and polymerization), phosphorus and chlorophyll increased. The oxidative stability of the oil so obtained increased with increasing temperature of heating and also... 

Yamaguchi, N. Yokoo, Y Koyama, Y. Studies on the browning reaction products on the stability of fats contained in biscuit and cookies. Nippon Shokuhin Kogyo Gakkaishi 1964, 11, 184—189. 

Yamaguchi, N. Effect of 3-deoxy-xylosone and its browning reaction product on the stabilities of fat and oil. Nippon Shokuhin Kogyo Gakkaishi 1969, 16, 94—96. 

This chapter wiU describe in detail their occurrence in the individual food commodities, their properties, stability and important reactions, their importance in human nutrition and physiology and their use as food colourings in food technology. A section of the chapter is devoted to the so-called enzymatic browning reactions that proceed as desirable, but also as adverse reactions in many foods of plant origin. Substances used as colour additives are described in Chapter 11, which focuses on food additives. Reaction pigments are mentioned in chapters dealing with the individual nutrients. 

The more extensive problem of correlating substituent effects in electrophilic substitution by a two-parameter equation has been examined by Brown and his co-workers. In order to define a new set of substituent constants. Brown chose as a model reaction the solvolysis of substituted dimethylphenylcarbinyl chlorides in 90% aq. acetone. In the case ofp-substituted compounds, the transition state, represented by the following resonance structures, is stabilized by direct resonance interaction between the substituent and the site of reaction. 

The suitability of the model reaction chosen by Brown has been criticised. There are many side-chain reactions in which, during reaction, electron deficiencies arise at the site of reaction. The values of the substituent constants obtainable from these reactions would not agree with the values chosen for cr+. At worst, if the solvolysis of substituted benzyl chlorides in 50% aq. acetone had been chosen as the model reaction, crJ-Me would have been —0-82 instead of the adopted value of —0-28. It is difficult to see how the choice of reaction was defended, save by pointing out that the variation in the values of the substituent constants, derivable from different reactions, were not systematically related to the values of the reaction constants such a relationship would have been expected if the importance of the stabilization of the transition-state by direct resonance increased with increasing values of the reaction constant. 

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