Maillard processing

K. M. Biemel, O. Reihl, J. Conrad, and M. O. Lederer, Formation pathways for lysine-arginine cross-links derived from hexoses and pentoses by Maillard processes, in G, 2002, 255-261. 

M. O. Lederer and R. G. Klaiber, Cross-linking of proteins by Maillard processes Characterization and detection of lysine-arginine cross-links derived from glyoxal and methylglyoxal, Bioorg. Med. Chem., 1999, 7, 2499-2507. 

F. Gerum, M. O. Lederer, and T. Severin, Cross-linking of proteins by Maillard processes Model reaction of an Amadori compound with W -acctyl-l -arginine, in F. 1998, 409. 

W. Baltes, in P. A. Pinot, H. V. Aeschbacher, R. F. HurreU, and R. Liardon, eds.. The Maillard Reaction in Food Processing, Human Nutrition and Physiology, Birkh Auser Vedag, Boston, Mass., 1990. 

The corrosive effects to be considered (mainly simple corrosion of metals) are, as would be expected from the edible nature of foodstuffs which are not excessively either acidic or basic but which may contain sulphur, less severe than those often encountered with inedible materials containing reactive substances. The importance of corrosive efiects where foodstuffs are concerned lies not so much in the action of the foodstuffs on the metal involved as in the resultant metal contamination of the foodstuff itself, which may give rise to off-flavours, in the acceleration of other undesirable changes (by the Maillard reaction for example), and in the possible formation of toxic metallic salts. Metal ions generally have threshold values of content for incipient taste effect in different liquid foodstuffs. Except in the case of the manufacture of fruit juices and pickles, process plant failure through corrosion must be rare. Nevertheless all foodstuffs, particularly liquid ones, should be regarded as potentially corrosive and capable of metal pick-up which may be undesirable. 

When the Maillard reaction was evaluated using 10 g/1 glucose for 30 minutes at 90 °C and 20 1 liquor ratio the fibre diameter increased by 3.5% xylose gave an increase almost twice as much but showed some yellowing. In this process accessibility of the fibre for dye molecules is increased, since the glucose molecules penetrate between the peptide chains. The reaction also introduces primary alcoholic groups, making the wool more dyeable with... 

Amino Acid Content. Amino acid content of field pea products is related to protein level, method of processing, and fraction (starch or protein). The protein fraction contains fewer acidic (glu, asp) amino acids than the starch fraction and more basic (lys, his, arg) amino acids than the starch fraction. Also, there are more aromatic (tyr, phe) amino acids, leu, iso, ser, val, and pro in the protein fraction than in the starch fraction (5). An amino acid profile of pea protein concentrate shows relatively high lysine content (7.77 g aa/16 g N) but low sulfur amino acids (methionine and cystine) (1.08-2.4 g aa/16 g N). Therefore, it is recommended that air classification or ultrafiltration be used because acid precipitation results in a whey fraction which contains high levels of sulfur amino acids (12,23). Also, drum drying sodium proteinates decreases lysine content due to the Maillard reaction (33). 

Brown proposed a mechanism where the enolate radical resulting from the radical addition reacts with the trialkylborane to give a boron enolate and a new alkyl radical that can propagate the chain (Scheme 24) [61]. The formation of the intermediate boron enolate was confirmed by H NMR spectroscopy [66,67]. The role of water present in the system is to hydrolyze the boron enolate and to prevent its degradation by undesired free-radical processes. This hydrolysis step is essential when alkynones [68] and acrylonitrile [58] are used as radical traps since the resulting allenes or keteneimines respectively, react readily with radical species. Maillard and Walton have shown by nB NMR, ll NMR und IR spectroscopy, that tri-ethylborane does complex methyl vinyl ketone, acrolein and 3-methylbut-3-en-2-one. They proposed that the reaction of triethylborane with these traps involves complexation of the trap by the Lewis acidic borane prior to conjugate addition [69]. 

The results obtained with this procedure are similar to those previously reported in the literature by Hangartner, Hagenguth et al and Zeman et al (4, 2, 5, 6). The major exception, being the complete lack of alkylated pyrazines and alkylated thiophenes. These odour-intensive compounds arise from the thermal decomposition of proteins and sulphur containing amino acids. They also develop in the thermally induced reaction of proteins with carbohydrates (Maillard reaction). The authors indicated above have demonstrated that these compounds are invariably produced during the thermal treatment of sludge, a process which is not used in this Authority. 

Maillard products are not only formed during cooking and other heat processing of foods, but also accumulate in some products that are rich in proteins and reducing sugars, e.g. condensed milk during months of storage at... 

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. 

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