Glucose thermal degradation products

The thermal degradation products of glucose and fructose have been extensively investigated (9-191. It can generally be concluded that both produce varying quantities of similar compounds. 

Under the conditions corresponding to the roasting of coffee, serine, threonine, and sucrose yield various substituted pyridines (51), furans, and furanones (52). Thirty-three pyridine derivatives were identified by Baltes and co-workers (51), Recently, 3-methylthiomethylpyridine was identified as one of the products of thermal degradation of the glucose-methionine Amadori intermediates (53). 

The products of caramelization are distributed between volatile and nonvolatile fractions. The composition of the volatile firaction is pretty well characterized, contrary to that of the nonvolatile fraction. Thus, neither is the structure of all compounds formed precisely known, nor are the processes which occur understood in detail (see, for instance, a review by Orsi ). The composition of the volatile fraction from the thermolysis of sucrose is the best recognized. The profound decomposition products from the decomposition in vacuo of sucrose arc water, carbon monoxide, carbon dioxide, formaldehyde, acetaldehyde, methanol, and ethanol. The detailed rates and temperature relationships suggest that, with the possible exception of ethanol, the other products result from secondary reactions of dehydration products. The low-molecular-weight portion of the nonvolatile fraction of the thermal degradation of sucrose contains D-fhictose, D-glucose,... 

Heyns et al. (1966a) identified it in the products formed when heating glucose. 2,3-Pentanedione is the main volatile compound formed by thermal degradation of Furaneol (1.100) after ih at 160°C in water at pH 5.1, it represents nearly half of the volatiles (GC). It is one of the aliphatic compounds identified in the thermal interaction of glucose and cysteine (Zhang and Ho, 1991). 

It was identified in the products of thermal degradation of glucose (Heyns et al., 1966a Walter and Fagerson, 1968), in the model reaction cysteine xylose (Ledl and Severin, 1973), and in model reactions of serine and threonine with sucrose (as well as in coffee) by Baltes and Bochmann... 

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