Reaction B Amadori Rearrangement

IV-substituted cation of enol form keto form 

Fresh garlic contains no iV -fructosylarginine however, in the manufacture of aged garlic extract (over 10 months or so), it increases progressively,24 providing potent 

More recently, acid hydrolysates have been analysed by HPLC.27 Furosine (see below) was the main product observed for dried figs and apricots, whereas furosine and the y-aminobutyric acid derivative, in about equal amounts, were the main products for prunes and dates. 2-Furoylmethyl-y-aminobutyric acid and -arginine were the most abundant products observed for commercial raisins, ranging from about 10 to 75 mg per 100 g of sample each. Most of the Amadori compounds present in raisins seem to have been formed during storage rather than processing. 

Using their method, Blank el al.21 examined the stability of fructosylglycine in solutions at different pH values. At 100 mM, 90 °C, 7 h, in water at pH 5, 6, 7, and 8, about 70, 31, 3, and 0% remained undegraded, whereas in 0.1 M phosphate the corresponding values were about 35, 0, 0, and 0%. After 1 h, the values had been about 98, 90, 60, and 34% and 95, 63, 30, and 24%, respectively. The degradation was clearly favoured both by higher pH and by the presence of phosphate. 

Compared with the /V-substituted glycosylamines, the l-amino-l-deoxy-2-ketoses are more stable to moist acid atmospheres, but are still heat-labile and decompose rapidly in mild alkali. They exert greater reducing power, although less than reduc-tones. They brown more easily with amino acids. Acid hydrolysis gives much compared with little HMF, but no hexose is recovered, in keeping with the reaction s being irreversible (however, see below). 

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Reaction A Sugar-amine condensation Reaction B Amadori rearrangement... 

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