VOLATILE COMPOUNDS FROM THE REACTION OF CYSTEINE, RIBOSE, AND PHOSPHOLIPID IN LOW-MOISTURE SYSTEMS

The headspace volatiles from Maillard reaction mixtures of cysteine and ribose heated at 185 degrees C with or without the addition of phosphatidylcholine, either dry or in the presence of a small quantity of water, were analyzed by GC-MS. The major products of the reaction were 3,5-dimethyl-1,2,4-trithiolane, 3-methyl-1,2,4-trithiane, 3,6-dimethyl-1,2,4,5-tetrathiane, and thieno[2,3-b]thiophene. Other products included a number of thiazoles and small amounts of some furanthiols and disulfides. Water had a significant effect on the relative amounts of volatiles produced; in particular, 1-(2-furanylmethyl)- 1H-pyrrole, two other 1-(2-furanylmethyl)alkyl-1H-pyrroles, and two bis(furan) compounds were only produced to any extent in systems without water. The addition of lipid had only a small effect on the volatile profile, with small amounts of lipid degradation products and lipid/Maillard interaction products formed. These results differ greatly from previous studies on the volatiles formed in reaction systems carried out in the presence of large quantities of water.