Amino acid-glucose mixtures

In fluorine-18 chemistry some enzymatic transformations of compounds already labelled with fluorine-18 have been reported the synthesis of 6-[ F] fluoro-L-DOPA from 4-[ F]catechol by jS-tyrosinase [241], the separation of racemic mixtures of p F]fluoroaromatic amino acids by L-amino acylase [242] and the preparation of the coenzyme uridine diphospho-2-deoxy-2-p F]fluoro-a-o-glucose from [ F]FDG-1-phosphate by UDP-glucose pyrophosphorylase [243]. In living nature compounds exhibiting a carbon-fluorine bond are very rare. 

The photoelectrochemical synthesis of amino acids from simple molecules has also been reported. Low efficiencies were observed in the conversion of mixtures of methane, ammonia and water to several amino acids on platinized TiOz Amino acids and peptides were reported when glucose replaced methane as the carbon source in a parallel experiment Higher quantum efficiencies (20-40%) were observed in the conversion of alpha-keto acids or alpha-hydroxy acids to the corresponding alpha-amino acids Moderate levels of enantiomeric selectivity (optical yields of about 50%) were reported when chiral starting materials were employed. Photoinduced Michael-like reactions were observed when alpha, beta unsaturated acids were used as substrates for the amino acid synthesis... 

Two-component systems (a) Glucose-amino acid systems Finely ground, equimolar mixture (0.3 g) was placed into a small test tube, a glass spacer added to hold down the solid in case of frothing and also to increase the contact of the mixture with the outside wall (see Figure 1), and the tube closed with an aluminum cap (Oxoid Ltd) to lessen the escape of volatiles. 

EXAMPLE PE AROMA ASSESSMENT OF 1 1 GLUCOSE AMINO ACID MIXTURE AT 180°... 

The results of this survey of the aromas produced over time by heating glucose—amino acid mixtures at a series of temperatures in the range 100-220° proved of great interest. Many mixtures were heated in the "dry" statB for the first time. Some produced the expected result, for example, methionine and phenylalanine led to potato and to floral aromas, respectively. Others were unexpected, for example, the large number of amino acids that was capable of producing chocolate aroma under one or other set of conditions. 

The KANOLD AB Company has developed a series of new materials, produced from mixtures of skimmed milk, glucose, and lysine (or other basic amino acids) by drying on a roller at a temperature of 125°C (1 ). Instead of skimmed milk, soya flour can be used as basic material. The new products, named milk-and soya-crumbs respectively, have a very pleasant odor... 

Table III. Mutagenic activity expressed as revertants per plate (TA98+S9) of model reaction systems (creatinine, glucose, amino acid in diethylene glycol-water 6 1, v/v). Samples in triplicates were directly withdrawn from the mixtures after 1, 2 and 4 h of reflux. 50 pi were used per plate. Comparison of mutagenic activity after corrections for spontaneous revertants between model mixtures containing alanine or glycine.

Table IV. Effect of Maillard reaction products (2-methylpyridine or 2,5-dimethylpyrazine) on the mutagenic activity of different model reaction mixtures (creatinine, D-glucose, amino acid in diethylene glycol-water 6 1, v/v) after 4 h of refluxing, 10-yl samples being directly withdrawn from the reaction mixtures and assayed with TA98 after S9 activation.

Figure 3. Browning intensity and mutagenicity of the glucose-amino acid mixtures on TA 100 as a function of time.

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