Development and evaluation of an automated solvent-assisted flavour evaporation (aSAFE)

Artefact-avoiding isolation of the volatiles from foods is a crucial step before analysis of odour-active compounds by gas chromatography (GC). In the past 20 years, solvent extraction followed by solvent-assisted flavour evaporation (SAFE) has become the standard approach, particularly prior to GC–olfactometry. The manual valve of the SAFE equipment, however, leads to suboptimal yields and the risk of a contamination of the volatile isolate with non-volatiles. We thus developed an automated SAFE (aSAFE) approach by replacing the manual valve with an electronically controlled pneumatic valve. The aSAFE provides clearly higher yields than the manual SAFE (mSAFE), notably from extracts high in lipids and for odorants with comparably high boiling points. Additionally, aSAFE substantially reduces the risk of non-volatiles being transferred to the volatile isolate. Full automatisation is possible by combining the aSAFE approach with an automated liquid nitrogen refill system as well as an endpoint recognition and shut-off system.