Main compounds responsible for off-odour of strawberries infected by Phytophthora cactorum

• Published in: Letters in applied microbiology Vol. 40; no. 4; pp. 255 - 259
• Main Authors: Jelen, H.H, Krawczyk, J, Larsen, T.O, Jarosz, A, Golebniak, B
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.01.2005; Blackwell Science
• Subjects: 4-ethyl guaiacol; 4-ethyl phenol; Aldehydes; Aldehydes - isolation & purification; analogs & derivatives; analysis; Benzyl Alcohols; Benzyl Alcohols - isolation & purification; Biological and medical sciences; chemistry; Chromatography, Gas; Fragaria; Fragaria - chemistry; Fragaria - microbiology; Fundamental and applied biological sciences. Psychology; GC‐O; growth & development; Guaiacol; Guaiacol - analogs & derivatives; Guaiacol - analysis; Guaiacol - isolation & purification; isolation & purification; Ketones; Ketones - isolation & purification; metabolism; Microbiology; Octanols; Octanols - isolation & purification; Odorants; off odors; phenols; Phenols - analysis; Phenols - isolation & purification; Phenylethyl Alcohol; Phenylethyl Alcohol - isolation & purification; Phytophthora; Phytophthora - growth & development; Phytophthora - metabolism; Phytophthora cactorum; postharvest diseases; strawberries; Terpenes; Terpenes - isolation & purification; volatile compounds; volatile organic compounds; Fungi; Fragaria; Applied microbiology; Dicotyledones; Angiospermae; Phycomycetes; Rosaceae; Spermatophyta; Thallophyta; Phytophthora cactorum
• ISSN: 0266-8254; 1472-765X; 1365-2673
• DOI: 10.1111/j.1472-765X.2005.01668.x

Aims:  Volatile compounds present in strawberries infected with Phytophthora cactorum, especially those responsible for the characteristic off‐odour of such fruits were the subject of this study. Methods and Results:  Six strawberry varieties (Redgauntlet, Selva, Korona, Tenira, Real, Pegasus) inoculated with P. cactorum strain (PC‐5), isolated from naturally infected fruit and one variety inoculated with 15 strains of P. cactorum in the laboratory were analysed. All the samples had a distinct, to a various degree, off‐odour reminiscent of watercolour paint with phenolic notes. Volatile compounds were isolated by solid phase microextraction and simultaneous distillation extraction methods. To detect compounds responsible for the characteristic off‐odour, gas chromatography–olfactometry was used. Two compounds were found to be responsible for the characteristic off‐odour of strawberries infected by P. cactorum: 4‐ethyl phenol and 4‐ethyl‐2‐metoxy phenol (4‐ethyl guaiacol). The content of these compounds in infected varieties ranged from 1·12 to 22·56 mg kg−1 and 0·14–1·05 mg kg−1 respectively. Other volatile compounds, not detected in noninoculated sound strawberries, were also identified: camphene, 1‐octene‐3‐ol, 3‐octanone, o‐cymene, phenyl methanol, cis‐linaloloxide, nonanal, phenyl ethyl alcohol, 2‐undecanone and α‐muurolene. Significance and Impact of the Study:  Volatile compounds responsible for the characteristic off‐odour of strawberries infected with P. cactorum were identified. Also compounds produced as a result of P. cactorum growth on strawberry fruit were characterized.