Abstract: Abstract：In this study, volatile compounds from cold-pressed and hot-pressed flaxseed oils produced from flaxseeds grown in Zhangjiakou, Hebei province were separated by headspace solid-phase micro-extraction (HS-SPME) and were analyzed by means of gas chromatography-mass spectrometry (GC-MS). The key aroma components of the flaxseed oils were identified by gas chromatography-olfactometry (GC-O). A total of 16 characteristic aroma components of hot-pressed flaxseed oil were detected, including 7 aldehydes, 4 heterocyclic compounds, 3 alcohols, one acid and one ester. A total of 14 characteristic aroma components were identified from cold-pressed flaxseed oil, including 6 aldehydes, 4 alcohols, 3 acids and 1 ester. Seven aroma components were found to be present in both the cold-pressed and hot-pressed oils. 2,5-Dimethylpyrazine, 2,3,5-trimethylpyrazine and (E)-2-hexenoaldehyde were the unique aroma components of hot-pressed flaxseed oil as important contributors to the roasted and greasy aroma. Acetic acid was the unique aroma component of cold pressed flaxseed oil.

Key words: flaxseed oil, headspace solid-phase micro-extraction, hot-pressed oil, cold-pressed oil, aroma components, gas chromatography-mass spectrometry-olfactometry