Abstract: In order to gain an in-depth understanding of the mechanism for the changes in the major ingredients and volatile compounds of cream during heating treatment, nuclear magnetic resonance (NMR) spectroscopy was used to analyze quantitatively the polar and apolar components of cream, and gas chromatography-mass spectrometry (GC-MS) was used to identify the volatile compounds of cream before and after heating treatment. NMR analysis revealed lactose as a major polar component, as well as lesser amounts of free amino acids, free fatty acids and organic acids; and triglycerides as major apolar components, as well as lesser amounts of diglycerides and monoglycerides. After heating treatment, the content of polar components, mainly including lactose and free amino acids, was reduced greatly, while the content of apolar components was reduced less. GC-MS analysis showed that the contents of short-chain fatty acids and aldehydes were increased less, whereas the contents of methyl ketones, lactones and Maillard reaction products were increased significantly, among which methional, maltol and furaneol were only detected in heated cream. The results showed that the formation of the Maillard reaction products and the growth of lipid-derived compounds during thermal treatment resulted in a reduction of polar components and fatty acids in cream, respectively, which provides a new idea for further research on cream flavor and products.

Key words: cream; aroma; nuclear magnetic resonance; gas chromatography-mass spectrometry