styrene

Technical specification

Assessment

The best way to detect the presence of styrene in soft drinks is as follows. Cover the sample with your hand and swirl the glass to release the aroma. Remove your hand and take a single long sniff. Repeat as necessary.

Amount of flavour per capsule

338 µg per capsule

Threshold

The flavour threshold of styrene in soft drinks is 110 µg / l.

Origins

Styrene can contaminate plastic bottles and, in turn, impart a taint to the soft drinks or juices packaged into these bottles. It can also arise from the action of contaminant yeasts and moulds. Use of defective carbon dioxide is occasionally to blame for styrene contamination incidents.

Importance

Styrene is often described by consumers as ‘chemical’, ‘plasticy’ (like polystyrene) or ‘contaminated’. When formed by yeasts or moulds, additional compounds such as 4-vinyl guaiacol and 1,3-pentadiene may be present which can modify the flavour making the drink more 'medicinal', 'smoky' in the case of guaiaco, or like kerosine in the case of pentadiene.

CAS registry number

100-42-5

Other names

• ethenylbenzene
• phenyl ethene
• phenyl ethylene
• styrol
• styrolene
• vinyl benzene
• vinyl benzol

Remarks

Other compounds can impart plastic-like notes to soft drinks. Samples containing this standard are best tasted in glass, rather than in plastic, to avoid loss of odour.

Threshold distribution

Capsules per pot

10