Detection of adulteration of cold-pressed lemon oil

✍ Scribed by D. McHale; J. B. Sheridan

• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 417 KB
• Volume: 3
• Category: Article
• ISSN: 0882-5734
• DOI: 10.1002/ffj.2730030308

✦ Synopsis

Adulteration of cold-pressed oil of the lemon Citrus limon with the lower quality steam-stripped oil still occurs on a major scale. It has been known for many years that substances with ultraviolet absorption characteristics similar to those of the coumarins and psoralens present naturally in cold-pressed lemon oil are added to the oil mixture to mask the adulteration. The present work has confirmed that substances such as ethyl p-dimethylaminobenzoate and 7-geranyloxycoumarin (auraptene) are still used to conceal the adulteration of cold-pressed lemon oil. 7-Methoxycoumarin (herniarin) and 5,7-dipropyloxy-4-methylcoumarin were also identified in certain commercial lemon oil samples. These compounds are not natural components of lemon oil and have not been associated previously with its adulteration.

A novel 5,8-disubstituted psoralen was detected in authentic cold-pressed lemon oil and identified as 5-isopent-2'-enyloxy-8-(2',3'-epoxyisopentyloxy)psoralen(l). The concentrations of the natural coumarins and psoralens in lemon oil have been determined. KEY WORDS Adulteration Citrus limon Lemon Lemon oil Coumann Psoralen 5-Isopent-2'-enyloxy-& (2' ,3'-epoxyisopentyloxy)psoralen Ethyl p-dimethylaminobenzoate 7-Geranyloxycoumarin Auraptene 7-Methoxycoumarin Herniarin 5,7-Dipropyloxy4methylcournarin Paper originally presented at the 17th Workshop of Essential Oils, Bad Bevensen, FRG, 28 September -1 October 1986.