Unlocking key odor-active compounds in cold-pressed, roasted, microwaved and steam-exploded flaxseed oils using a sensomics approach

Currently, roasting and microwaving are the main methods used for fragrant flaxseed oils; however, the effect of steam explosion on the odorants in flaxseed oils remains unclear. Herein, 99 odorants were identified in cold-pressed flaxseed oil (CPFO), roasted flaxseed oil (RFO), microwaved flaxseed oil (MFO) and steam-exploded flaxseed oil (SEFO). Total 58 odor compounds were detected with flavor dilution (FD) factors ranged from 1 to 729. Compared with CPFO, abundant heterocyclic compounds were formed in RFO, MFO and SEFO. Heterocyclic compounds are more concentrated in SEFO-1.2 MPa than in SEFO-0.8 MPa. CPFO demonstrated distinct grassy and slightly nutty and pungency smell. RFO and MFO exhibited distinct roasted and slightly fishy and pungent odor. SEFO-0.8 MPa exhibited an excellent roasted odor, while SEFO-1.2 MPa presented strong roasted odor and burned odor. Thus, this study offers novel insights into the feasibility of steam explosion as an alternative in the processing of fragrant flaxseed oils. • aldehydes, ketones, alcohols, acids were main odorants in cold-pressed flaxseed oil • Roasted, microwave, steam explosion can lead to pyrazines formation in flaxseed oils • GC-IMS-fingerprint can distinguish flaxseed oils from different preheat treatments • Steam explosion treated flaxseed oil at 0.8 MPa with excellent roasted odor