Evaluation of non-degrading physical approaches for sustainable odour reduction in flax fibres

Flax ( Linum usitatissimum L. ) fibres are increasingly used in textiles, composites and eco-designed products due to their renewable nature, mechanical strength, and environmental compatibility. Nevertheless, their widespread use is hampered by the emission of unpleasant odours and volatile organic compounds (VOCs), which compromise consumer acceptance in applications such as automotive interiors and indoor materials. This study investigated two solvent-free deodorization techniques: hydrodistillation (HD) and steam distillation (SD), applied to dew-retted and scutched flax fibres. Odour intensity was evaluated by a sensory panel, while VOC emissions were quantified by headspace solid-phase microextraction followed by gas chromatography–mass spectrometry analysis (HS-SPME-GC-MS). Both treatments significantly decreased odour intensity (p < 0.05), with HD providing a stronger reduction and yielding more homogeneous results. Chemical analysis confirmed marked decreases in aliphatic aldehydes (hexanal, heptanal, octanal, nonanal, and decanal) and furans, known to be key contributors to unpleasant sensory notes. These findings demonstrate that HD and SD are efficient, non-degrading, and solvent-free processes that improve the olfactory acceptability of flax fibres while remaining compatible with sustainable and industrial practices. By mitigating odour without compromising fibre integrity, these methods support the broader adoption of flax fibres in odour-sensitive markets and align with the principles of green chemistry. • Comparison of two extraction methods to achieve odour intensity reduction • Sensory and physicochemical analyses of fibres before and after extraction • Hydrodistillation and steam distillation made possible to reduce odour emission