| Rapeseed oil could form heavy roasting flavor during microwave pretreatment. The key components of roasting flavor of rapeseed oil were identified by the combination of headspace solid phase microextraction-GC-MS and aroma factor dilution analysis. The changes of free sugars, free amino acids, temperature and rapeseed water content were investigated in the microwave process of rapeseed. The results showed that a total of 13 volatile components of the roasting flavor were identified in microwave pressed rapeseed oil, including nine kinds of pyrazines, one alcohol, one aldehydes, one furan, and one thiazole. Six substances had the greatest contribution to the roasting flavor of rapeseed oil, including 2,5-dimethylpyrazine, 2,6-dimethylpyrazine, 5-methyl furfural, 2-ethyl-6-methylpyrazine, 2-ethyl-5-methylpyrazine and 3-ethyl-2,5-dimethylpyrazine, because their factor dilutions were greater than 32. During the process of microwave 0-8 min, free sugars (fructose, glucose) and free amino acids showed a decreasing trend except saccharose. According to the content variation and correlation analysis, the precursor substances involved in the Maillard reaction might be glucose, fructose, aspartic acid, leucine and lysine. |
