Effect of high hydrostatic pressure on the volatile components of a glucose-lysine model system

An aqueous glucose-lysine model system (initial pH 10.1) was incubated at 60 degrees C and atmospheric pressure (system A) or 600 MPa (system B) to the same absorbance value at 420 nm. Volatile reaction products were isolated by solvent extraction and analyzed by gas chromatography/mass spectrometry. Thirty-two compounds were identified; most contained nitrogen, and pyrazines predominated. Yields of all compounds were suppressed at 600 MPa. Further incubation, at either atmospheric pressure (system C) or 600 MPa (system D), of system A, resulted in lower yields of many compounds at 600 MPa, compared to prolonged incubation at atmospheric pressure. Many of the compounds reported may be formed by, or subsequently react via, aldol condensation. The observed differences among the systems in the profiles and yields of volatile compounds suggest that aldol condensations increase in rate in the systems under pressure.