Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Maillard furosine

The extent of heat-induced changes in protein-rich foods can be measured by determining some early Maillard reaction products (O Brien and Morrissey, 1989). Acid treatment of protein-bound or free A -fructoselysine liberates lysine, with a yield of 50%, and two other amino acids, furosine (20%) and pyridosine (10%) (Figure 13.1). The three products that result from hydrolysis of A -lactuloselysine are formed in the proportions of approximately 5 3 to 4 1 to 2, however the yield of different derivatives is variable. Therefore, in order to use these unique amino acids as indicators of changes in lysine content, the hydrolysis should be carried out in strictly-defined conditions. Furosine is present in various food products in a very wide range of concentrations (Table 13.2). [Pg.289]

Guerra-Hernandez, E., Corzo, N. and Garcia-Villanova, B. (1999). Maillard reaction evaluation by furosine determination during infant cereal processing, J. Cereal ScL, 29, 171-176. [Pg.311]

Several markers for the Maillard reaction have been described in the literature. For example, the product initially formed between glucose and lysine is partly transformed into furosine (Heyns et ah, 1968) on acid hydrolysis. Conversely, the fluorescent amino acid pentosidine (Sell and Monnier, 1989) is an advanced glycation endproduct (AGE) and may form covalent bonds between proteins (cross-linking). Furthermore, the Maillard reaction leads to an increase in characteristic fluorescence (excitation 370 nm, emission 440 nm) (Monnier et ah, 1984 Pongor et ah, 1984). [Pg.44]

HPLC. Furosine and pentosidine, indicators of the initial and advanced stages of fhe Maillard reaction, respectively, increased in glucose-exposed slices (figs. 3,4 fable 3). Hydroxylysylpyridinoline apparenfly did nof form in fhe demineralized dentin at 37°C, as it did not increase in dentin exposed at 37°C (table 3). [Pg.50]

Figure 9.8 Initial steps of the Maillard reaction with the formation of furosine (after hydrolysis with 7.8 M HCi) as well as of. Y-s-carboxymethyl lysine and erythronic acid (from Erbersdobler... Figure 9.8 Initial steps of the Maillard reaction with the formation of furosine (after hydrolysis with 7.8 M HCi) as well as of. Y-s-carboxymethyl lysine and erythronic acid (from Erbersdobler...
Thiazolium salt XTT has been used to evaluate the extent of the Maillard reaction in UHT (ultra-high-temperature)-treated milk, where it proved more rapid and convenient than determination of lactulose, HMF, or furosine.451 To establish the nature of the Maillard reaction products (MRP) involved, the interaction of the aminoreductone from lactose and n-butylamine (Amax = 319.5 nm) with MRP was studied. Excellent correlation (r = 0.967, n = 19) was found between the increased absorbance at 319.5 nm and XTT reducibility, as measured at 492 nm, near Alliax for the formazan, the reduction product of XTT. [Pg.127]

M. Rada-Mendoza, A. Olano, and M. Villamiel, Furosine as indicator of Maillard reaction in jams and fruit-based infant foods, J. Agric. Food Chem., 2002, 50, 4141 —4145. [Pg.174]

J. A. Rufian-Henares, Guerra-Hemandez, and B. Garcia-Villanova, Maillard reaction in enteral formula processing furosine, loss of o-phthalaldehyde reactivity, and fluorescence, Food Res. Int., 2002, 35, 527-533. [Pg.174]

This leads to a decrease in the biological value of the protein. Milk is a good model to study the nutritional effects of the Maillard reaction because of its high levels of lysine and lactose. In processed milks, unavailable lysine is present only as e-deoxylactulosyllysine (9,24) its level which depends on the type of treatment can be measured by the furosine method (24,31). [Pg.97]

Furosine, a marker of the Maillard reaction product, is a valuable indicator of food protein quality. It is a marker for thermal treatment in foodstuffs and is directly related to the loss of lysine availability. IPC was employed to determine furosine content in beverages based on soy milk and cow milk supplemented with soy isoflavones [39]. Furosine was also analyzed in 60 commercial breakfast cereals to assess their protein nutritional values. The higher the protein content in the formulation, the higher the furosine levels [40]. A simple IPC technique that uses 1-octanesulfonic acid as the IPR allowed the selective determination of histamine levels in fermented food [41]. [Pg.163]

In heat treated or stored food products several amino acids are not fully available because of derivatization or crosslinking reactions. Since 30 years furosine is known as a useful indicator of early Maillard reaction which is applied in food science, nutrition and medical biochemistry. Recently more sensitive analytical methods for furosine determination are available which have again increased the attractivity of this important indicator. Lately, N -carboxymethyllysine (CML) became available as another marker of special interest, because CML is a more useful indicator of the advanced heat damage by Maillard reaction than furosine. In addition, CML has the advantage to indicate reactions of lysine with ascorbic acid or ketoses such as fructose. Indicators for protein oxidation of sulfur amino acids are methionine sulfoxide and cysteic acid. An established marker for cross-linking reactions is lysinoalanine, which also indicates protein damages due to processing under alkaline conditions. Other markers formed as a consequence of alkaline treatment are D-amino acids. [Pg.45]

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). [Pg.46]

Furosine and Other Markers for the Initial Stage of the Maillard Reaction... [Pg.46]

On the other hand, furosine has the big advantage that it is a direct marker for a real existing reaction product of lysine, which has nutritional relevance. It represents the main reaction product of the initial stage of Maillard condensation and in this way a sector of heat damage, which is most interesting for heated milk and milk products. [Pg.47]

In dairy products also hydroxymethylfurfural (HMF) and lactulose are common markers. For the determination of HMF, which also results from the Maillard condensation (18), precursors of browning products in milk are transformed to HMF after addition of oxalic acid and following heating (79). Principally, the HMF value of a milk can be used as an indicator for the heating process, but data from literature offer a wide range for this value which suspect that the HMF determination is insufficiently reproducible between laboratories. In particular, the level of HMF in untreated material, measured during the determination of "total HMF" and subtracted from the levels in treated milks, is a source of variation (20). However a comparison between the furosine and the HMF-method demonstrated the usefulness of the HMF-method as a rapid and simple measure of heat damage caused by the UHT process (77). [Pg.47]

In the advanced and late "Maillard reaction" the furosine method is not valuable since the Amadori products lead to further compounds. Therefore the amount of available lysine in severely damaged foods is underestimated. In the case of fructose rich food (e.g. special diets for diabetics or products which are sweetened with honey or concentrated fruit juice) similar false conclusions are possible since glucoselysine which is formed from fructose during the "Maillard reaction" is not a precursor for furosine. [Pg.48]

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). [Pg.209]

The determination oj furosine (LySfu )- This method is based on the fact that lysine blocked in an early Maillard reaction in the form of e-N-deoxyketosyl-lysine yields upon acid hydrolysis a constant proportion of furosine (Fig. 2) (e-N-2-furoylmethyl-L-lysine). The blocked lysine corresponds, then, to 3-1 times furosine. The available lysine value can then be calculated by subtracting the blocked lysine value from the theoretical lysine value (ThL = lysine present in the unheated milk sample). [Pg.394]

Obviously, available lysine can then be calculated from blocked lysine, taking the theoretical lysine value as 100. In this case, (Fig. 7), the correlation equation with ALV n has no special meaning, since this regression was used to validate the furosine method. In our experience, the furosine method has been very useful for routine control of lysine blockage in industrial milk samples. It should be borne in mind, however, that the method as described can only be used to determine early Maillard damage to lysine (deoxyketosyl form). [Pg.400]


See other pages where Maillard furosine is mentioned: [Pg.233]    [Pg.43]    [Pg.52]    [Pg.57]    [Pg.58]    [Pg.67]    [Pg.97]    [Pg.100]    [Pg.100]    [Pg.567]    [Pg.276]    [Pg.419]    [Pg.424]    [Pg.11]    [Pg.12]    [Pg.95]    [Pg.104]    [Pg.357]    [Pg.334]    [Pg.895]    [Pg.3949]    [Pg.334]    [Pg.30]    [Pg.343]    [Pg.47]    [Pg.147]    [Pg.392]    [Pg.705]    [Pg.705]   
See also in sourсe #XX -- [ Pg.280 , Pg.280 , Pg.285 , Pg.285 ]




SEARCH



Furosine

Maillard

© 2024 chempedia.info