| Headspace solid phase microextraction-gas chromatography-mass spectrometry was used to determine the volatile odor substances in different grades of rapeseed oils. The headspace solid phase microextraction conditions (extraction head, extraction temperature, adsorption time, and desorption time)were optimized by single factor experiment using total peak area and number of peaks as indicators. Under the optimal conditions, the volatile odor substances in the first, third and fourth grade rapeseed oils were identified.The results showed that the optimal headspace solid phase microextraction conditions were obtained as follows: with 50/30 μm CAR/DVB/PDMS as extraction head, adsorption time 30 min, extraction temperature 75 ℃, and desorption time 2 min. Under the optimal extraction conditions, the most volatile odor substances of rapeseed oil were detected by GC-MS with the largest total peak area, and 11,17 and 25 volatile flavor components were measured in the first, third and fourth grade rapeseed oils, respectively. The main volatile odor substances of the first grade rapeseed oil were aldehydes, accounting for 5794%; the main volatile odor substances of the third and fourth grade rapeseed oils were thioside degradation products and heterocyclic substances, accounting for 37.33%, 50.52% and 17.50%, 25.90%,respectively. |
