Odour-active compounds of an Eisenia foetida protein powder. Identification and effect of delipidation on the odour profile

The odour-active compounds (OAC) of an Eisenia foetida (Ef) protein powder were determined using a detection frequency gas chromatography–olfactometry method. They were isolated by a Solvent-Assisted Flavour Evaporation Extraction (SAFE) method. Sixty-eight compounds were designated as OAC, 41 of which were identified. Fifty-one percent of the identified compounds came from lipid oxidation. A Soxhlet delipidation method, with hexane, and an ultrasound extraction method, with a chloroform/methanol mixture, were used in order to dearomatize the Ef protein powder. The effect of delipidation on the OAC was studied. The Soxhlet and the ultrasound methods eliminated 70.5% and 97.7% of the OAC, respectively. The Ef protein powder was characterised by animal, chemical, earthy, floral, fruity and vegetable attributes. Soxhlet extraction reduced the vegetable and the herbaceous attributes, whereas ultrasound extraction reduced the chemical, earthy, floral, fruity and Maillard attributes.