Food analysis Maillard reaction

Human perception of flavor occurs from the combined sensory responses elicited by the proteins, lipids, carbohydrates, and Maillard reaction products in the food. Proteins Chapters 6, 10, 11, 12) and their constituents and sugars Chapter 12) are the primary effects of taste, whereas the lipids Chapters 5, 9) and Maillard products Chapter 4) effect primarily the sense of smell (olfaction). Therefore, when studying a particular food or when designing a new food, it is important to understand the structure-activity relationship of all the variables in the food. To this end, several powerful multivariate statistical techniques have been developed such as factor analysis Chapter 6) and partial least squares regression analysis Chapter 7), to relate a set of independent or "causative" variables to a set of dependent or "effect" variables. Statistical results obtained via these methods are valuable, since they will permit the food... 

It is well known that the Maillard reaction in foods is initiated by the formation of colorless and tasteless intermediates, which preferentially are formed in low-moisture systems ( ,5.). In this way by reaction of glucose with amino acids fructose-amino acids are formed via Amadori rearrangement of the primary glucosyl-ami-no acids (1 ). Fructose-amino acids e.g. have been isolated from freeze-dried apricots and peaches ( 6,7,8j. Amadori compounds arising from aldoses and amino acids are formed during drying of foods of plant origin and can be easily detected by amino acid analysis (j>). 

F. Bressa, N. Tesson, M. D. Rosa, A. Sensidoni, and F. Tubaro, Antioxidant effect of Maillard reaction products Application to a butter cookie of a competition kinetics analysis, J. Agric. Food Chem., 1996, 44, 692-695. 

Hodge stimulated research on these l-amino-l-deoxy-n-fructoses, not only by his fundamental contributions, but even more by his review, which mentioned the problems encountered during crystallization, and formulated questions about possible intermediates. Their basic role in the nonenzymic browning of foods (Maillard reaction) is another aspect of the biochemical importance of these products in Natiu-e, which has been proved by later work on the stimulation of protein synthesis and the analysis of liver tissues. ... 

AMES, J. M., ARNOLDi, A., BATES, L. and NEGRONI, M. (1997). Analysis of the methanol-extractable non-volatile Maillard reaction products of a model extmsion-cooked cereal product. J. Agric. Food Chem. 45, 1256-1263. 

Schwab W. (1998) Application of stable isotope ratio analysis explaining the bioformation of 2,5-dimethyl-4-hydroxy-3(2//)-furanone in plants by a biological Maillard reaction. (Furaneol). J. Agric. Food Chem. 46, 2266-9. 

A hundred thousand years ago, Man had begun to prepare food with the aid of fire, and started chemistry while cooking. With help from the Maillard reaction, the taste of his food became more sophisticated and pleasant. The typical smell of warm, crusty bread, the marvellous taste of a roast, the fine odour of roasted coffee, the spicy aroma and the colour of beer, result all from this little-known named reaction. Precise analysis of food ingredients and the development of highly specialised processing technologies allow for the industrial-scale preparation of tasty, appealing and readily available meals and snacks, which are... 

Marsili, R.T. Shelf-life prediction of processed mUk by solid-phase microextraction, mass spectrometry, and multivariate analysis. J. Agric. Food Chem. 48, 3470-3475 (2000). Mastrocola, D. and Munari, M. Progress of the Maillard reaction and antioxidant action of Maillard reaction products in preheated model systems during storage. J. Agric. Food Chem. 48, 3555-3559 (2000). 

The book starts with an introductory overview, which is intended to refresh the reader s memory on key aspects of free radicals and reactions thereof. Subsequent sections cover free radicals and food chemistry, natural antioxidants, and nutritional biochemistry and health. In the food chemistry section, topics range from analysis of free radicals within food matrices to Maillard reactions, emulsions, dairy, and meat products. In the antioxidant section, results are presented on the efficacy of antioxidants from tea, seeds, and selected naturally occurring compounds. Finally, in the nutritional biochemistry and health section, free radical inhibition is discussed in relationship to biochemical paths and cancerous cell cultures. 

The first main intermediates formed during the Maillard reaction in the most common food items are the Amadori compounds with the fructoselysine moiety (fructoselysine, lactuloselysine or maltuloselysine) which are degraded during the acid hydrolysis of the protein, necessaiy for amino acid analysis. However they can be estimated by analyzing for furosine which is formed during hydrolysis with strong HCL (Fig. 1). 

Several methods have been developed for assaying non-enzymatic glycosylation. As far as biological systems are concerned, these have been extensively reviewed by A. J. Furth in 1988 (5). They include both assays on intact proteins after chemical degradation and selective detection of e.g. 5-hydroxymethylfurfural (HMF) and formaldehyde using the thiobarbituric assay (TEA), and assays on protein hydrolysates with or without previous reduction of the protein-bound Amadori compound. In this last case, the analysis is based on the determination of furosine which is specifically formed from lysine Amadori compounds with a yield of approximately 30% (6). The furosine method, originally developed for milk (7), has been the subject of several analytical improvements both for food products (8) and biological materials (9). More recently, another method has been proposed to evaluate the extent of early Maillard reaction in milk products. This method is based on direct measurement of the Amadori product lactuloselysine which is released after complete enzymatic hydrolysis (10). 

Modification of food proteins with reducing sugars through Maillard reaction has been evaluated by various analytical methods determination of free amino groups, amino acid analysis after acid hydrolysis, detection of brownish pigments and fluorescent compounds. Some Maillard products have also been analyzed immunochemically using specific antibodies. 

Extensive reports of the Maillard reaction can be found in the scientific literature, most focus on aqueous systems, and few monitor the reaction with time. An interesting system for processing liquid streams of reactants under precise time-temperature conditions was described by Stahl and Parliment [1]. Analysis of the data resulted in a plot of flavor and color generation with time from which the kinetics of the reactions could be easily calculated. Gaining the same sort of data from food matrices that dehydrate on heating is more difficult, and there are few published reports. 

Intake of diets rich in MRPs exerts negative health effects (reviewed in 9). Compared to mother milk, infant formulas contain by 1 to 2 orders of magnitude higher amounts of CML (35- to 100-fold in mean)" . Here not CML, but a mixture of essentially unknown fluorescent Maillard compounds was measured, yielding a 23-fold difference between mother milk and formulas. Considering that hydrolyzed formulas have twice higher levels of CML and Maillard products the results obtained with fluorescence and CML analysis fit well. This observation confirms that fluorescent Maillard products are good indicators of the reaction development in food. 

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