Participation in Maillard reaction

Saccharides participate in Maillard reactions. Polysaccharides form a compact film on the snrface in the beginning of frying and produce a crispy crust. The level of dietary fiber and resistant starch may change, but not significantly. 

Strecker aldehydes are quantitatively the major products of the Maillard reaction. In addition to their intrinsic flavor, they are very reactive and participate in numerous reactions that make additional contributions to flavor development in foods. There is a lack of information on the reaction kinetics of these Strecker aldehydes as well as other flavor compounds. Thus a kinetic study on the formation of methional and two secondary products (dimethyl disulfide and 2-acetylthiophene) from the reaction of amino acids (0.075 mole) and glucose (0.5 mole) in aqueous model systems was conducted. Systems were heated at temperatures from 75 to 115°C at times from 5 min. to 7.5 h and pH s of 6, 7, and 8. Kinetic data are presented and discussed. 

Milk powder contains several useful components, namely protein and lactose. Lactose is a reducing sugar that undergoes the Maillard reaction to produce flavour and colour. The proteins as well as participating in the Maillard reaction have useful emulsifying abilities. These benefits are only obtained if the lactose is dissolved and the proteins dissolved or dispersed. 

The health impairing and toxic elfects of oxidation of lipids are due to loss of vitamins, polyenoic fatty acids, and other nutritionally essential components formation of radicals, hydroperoxides, aldehydes, epoxides, dimers, and polymers and participation of the secondary products in initiation of oxidation of proteins and in the Maillard reaction. Dilferent oxysterols have been shown in vitro and in vivo to have atherogenic, mutagenic, carcinogenic, angiotoxic, and cytotoxic properties, as well as the ability to inhibit cholesterol synthesis (Tai et ah, 1999 Wpsowicz, 2002). 

In summary, there are at least four ways in which residual moisture in the amorphous state can impact on chemical reactivity. First, as a direct interaction with the drug, for example, in various hydrolytic reactions. Second, water can influence reactivity as a by-product of the reaction, by inhibiting the rate of the forward reaction, for example, in various condensation reactions, such as the Maillard reaction. Third, water acting locally as a solvent or medium facilitating a reaction, without direct participation. Finally, by virtue of its high free volume and low Tg, water can act as a plasticiser, reducing viscosity and enhancing diffusivity [28]. 

This book is a result of the first symposium on the Maillard reaction held in this country (the second in the world2). Panel discussions with audience participation were held on the subjects of food and nutritional benefits of Maillard reaction products and the toxicology of Maillard reaction products but are not reported here. Interaction between participants during this meeting helped cement relations for continued help and perhaps will promote some new areas for cooperative research between American and foreign scientists. This symposium was also an important element in the training of graduate students it provided them with increased awareness of the breadth of the scientific field. We hope that it is true of each of you ... 

Lipids play an important part in the development of aroma in cooked foods, such as meat, by providing a source of reactive intermediates which participate in the Maillard reaction. Phospholipids appear to be more important than triglycerides. The addition of phospholipid to aqueous amino acid + ribose mixtures leads to reductions in the concentrations of heterocyclic compounds formed in the Maillard reaction. This effect could be due to lipid oxidation products reacting with simple Maillard intermediates, such as hydrogen sulfide and ammonia, to give compounds not normally found in the Maillard reaction. The precise nature of the odoriferous products obtained from lipid - Maillard interactions is dictated by the lipid structure and may depend on the fatty acid composition and the nature of any polar group attached to the lipid. 

During extrusion, general browning typified by carameli-zation, Maillard, and oxidative decomposition reactions are paramount in flavor compound formation. Temperature and shear conditions occurring during extrusion can provide the chemical and physical means whereby complex starch and protein can be partially degraded to provide reactants that can then participate in browning. 

Knowledge of the Maillard reaction is being extended very actively in many different ways. The participation of free radicals has already been dealt with in Chapter 2 and work on colour and flavour aspects is being deferred to Chapters 4 and 5, respectively. This chapter deals with a number of relatively disparate topics, namely, the effects of pH, high pressure, 7g, and the use as reactants of amines other than amino acids, of lipids, and of oligo- and polysaccharides, as well as the determination of a-dicarbonyl intermediates, control of aldol/retroaldol reactions, fluorescence, kinetic aspects, and sites of protein glycation. 

Of the different types of lipids in foods, the phospholipids, being more unsaturated, are particularly important in relation to aroma formation in meat.151 The aroma of cooked meat was not affected by the prior extraction of triglycerides with hexane, but the use of a more polar solvent (chloroform-methanol), which extracts all lipids, including phospholipids, resulted, after cooking, in the replacement of the meaty aroma by a roast or biscuit-like one. This was reflected in the volatiles, the dominant aliphatic aldehydes and alcohols being replaced by alkylpyrazines. This implies that the participation of the lipids in the Maillard reactions inhibited the formation of heterocyclic compounds. 

All amino acids, peptides, and proteins can participate in the Maillard reaction. Reactivity of essential and nonessential amino acids is of importance in relation to, for example, intravenous (parenteral) feeding, but, in general, by far the greatest attention is paid to lysine, because it is not only an essential amino acid, which may be limiting in the diet, but also because its e-amino group remains reactive, even in peptides and proteins. 

Biologically, proteins have had most of the attention with regard to glycation, but, in principle, it has always been realised that any amino compound bearing at least one hydrogen atom on its nitrogen is able to participate in the Maillard reaction. 

Trehalose, a disaccharide sweetener, 45-50 percent as sweet as sucrose, was given GRAS status in 2000. It is naturally found in mushrooms, honey, lobster, shrimp, and foods made with yeast. It has been used in Japan for decades, and is commercially produced from starch by bacterial enzymes.98 Besides its mild sweetening power, it maintains cell structure during freezing and dehydration of foods. It is a nonreducing sugar, so it does not participate in the Maillard reaction (will not brown) and helps to protect the color of processed foods.99... 

Hydrolyzed vegetable protein (HVP) is one of the earliest known forms of thermal reaction or process flavors (7,2). HVPs can been produced by acid (HCl) or enzyme (proteolytic) hydrolysis of a protein source (usually of plant origin) to form principally amino acids (7,5-5), which, themselves, can impart taste (e.g. monosodium glutamate) or participate in subsequent thermal reactions, e.g. Maillard reaction, to form aroma compounds (6,7). Among the numerous process parameters involved in the production of HVP, the substrate or protein source material may have a great in5)act on the resulting amino acid profile and flavor characteristics of the final product (7,5). 

---