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


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 alpha-muurolene.


CONCLUSIONS
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.
Jeleń
H H
HH
Institute of Food Technology, The August Cieszkowski Agricultural University of Poznan, Poznan, Poland. henrykj@au.poznan.pl
Krawczyk
J
J
Larsen
T O
TO
Jarosz
A
A
Gołebniak
B
B
D000447:Aldehydes / Q000302:isolation & purification; D001592:Benzyl Alcohols / Q000302:isolation & purification; D000081008:Bicyclic Monoterpenes; D002849:Chromatography, Gas; D031985:Fragaria / Q000737:chemistry / Q000382:microbiology*; D006139:Guaiacol / Q000031:analogs & derivatives* / Q000032:analysis / Q000302:isolation & purification*; D007659:Ketones / Q000302:isolation & purification; D000442:Octanols / Q000302:isolation & purification; D009812:Odorants; D010636:Phenols / Q000032:analysis / Q000302:isolation & purification*; D010626:Phenylethyl Alcohol / Q000302:isolation & purification; D010838:Phytophthora / Q000254:growth & development* / Q000378:metabolism*; D013729:Terpenes / Q000302:isolation & purification
D000447:Aldehydes; D001592:Benzyl Alcohols; D000081008:Bicyclic Monoterpenes; D007659:Ketones; D000442:Octanols; D010636:Phenols; D013729:Terpenes; C008664:nonanal; D006139:Guaiacol; C017582:3-octanone; C042291:4-ethylphenol; C084991:4-ethylguaiacol; C019286:camphene; D010626:Phenylethyl Alcohol; C038844:1-octen-3-ol