TY - JOUR

T1 - (5 E/ Z,7 E,9)-Decatrien-2-ones, Pineapple-like Flavors from Fomitopsis betulina - Structure Elucidation and Sensorial Properties

AU - Grosse, Miriam

AU - Pendzialeck, Tim

AU - Fohrer, Jörg

AU - Berger, Ralf G.

AU - Krings, Ulrich

N1 - Funding information: It remains a matter of speculation why a higher fungus should synthesize these compounds. However, in their natural habitats, wood-destructing fungi are exposed to many microbial and animal enemies as well as organisms spreading their spores. Thus, it is not surprising that they interact with their highly populated environment through volatile chemical signals. (20) Like the pineapple constituents (1,3 E ,5 Z )-undecatriene and (1,3 E ,5 Z ,8 Z )-undecatetraene, which are known to act as algal pheromones, (5 E / Z ,7 E ,9)-decatrien-2-ones, with their highly similar three-dimensional structure, may serve as signaling compounds in fungi. (21) The biogenesis of the decatrienones is obscure. Although first detected in cell cultures supplemented with cabbage cuttings in concentrations of 1.1 mg/L, a particular precursor role of this nutrient is doubtful. Fatty acids may serve as a precursor molecule for the formation of methyl ketones along the ?-oxidation. (22) Fruity constituents of high structural similarity, such as undecatrien-3-one in yuzu ( C. junos ), may be formed along this pathway. An analogous origin of the decatrienones of F. betulina would require an odd-numbered unsaturated fatty acid, as they in fact occur in basidiomycetes. Supplementing labeled precursors will clarify this question. Another aim of future research could investigate in detail the interaction of decatrienones with human odorant receptor proteins. The authors are grateful to the Lower Saxony Ministry of Science and Arts for support through the research cluster “Bioeconomy 2.0: Innovation Potentials of Side-Streams of Food Processing”. The authors declare no competing financial interest.

PY - 2020/9/23

Y1 - 2020/9/23

N2 - During the cultivation of the edible mushroom Fomitopsis betulina on agro-industrial side streams, a pleasant flavor strongly reminiscent of pineapple was perceived. Aroma extract dilution analyses identified two flavor components with a distinct pineapple odor. On the basis of mass spectrometric data, a Wittig reaction of (E)-penta-2,4-dien-1-yltriphosphonium bromide with ethyl levulinate was conducted. The resulting (5E/Z,7E,9)-decatrien-2-ones were identical to the compounds isolated from the fungal culture. Some structurally related methyl ketones were synthesized, confirmed by nuclear magnetic resonance and mass spectrometry, and their odor was characterized. The lowest odor threshold and most characteristic pineapple-like odor was found for (5Z,7E,9)-decatrien-2-one. Global minimum energy calculation of the methyl ketones and the comparison to (1,3E,5Z)-undecatriene, a character impact compound of fresh pineapple, showed that a chain length of at least 10 carbon atoms and a terminal double bond embedded in a "L"-shaped conformation were common to compounds imparting an intense pineapple-like odor. Both (5E/Z,7E,9)-decatrien-2-ones have not been described as natural flavor compounds.

AB - During the cultivation of the edible mushroom Fomitopsis betulina on agro-industrial side streams, a pleasant flavor strongly reminiscent of pineapple was perceived. Aroma extract dilution analyses identified two flavor components with a distinct pineapple odor. On the basis of mass spectrometric data, a Wittig reaction of (E)-penta-2,4-dien-1-yltriphosphonium bromide with ethyl levulinate was conducted. The resulting (5E/Z,7E,9)-decatrien-2-ones were identical to the compounds isolated from the fungal culture. Some structurally related methyl ketones were synthesized, confirmed by nuclear magnetic resonance and mass spectrometry, and their odor was characterized. The lowest odor threshold and most characteristic pineapple-like odor was found for (5Z,7E,9)-decatrien-2-one. Global minimum energy calculation of the methyl ketones and the comparison to (1,3E,5Z)-undecatriene, a character impact compound of fresh pineapple, showed that a chain length of at least 10 carbon atoms and a terminal double bond embedded in a "L"-shaped conformation were common to compounds imparting an intense pineapple-like odor. Both (5E/Z,7E,9)-decatrien-2-ones have not been described as natural flavor compounds.

KW - (5 E/ Z,7 E,9)-decatrien-2-ones

KW - pineapple flavor

KW - structure-activity relationship

UR - http://www.scopus.com/inward/record.url?scp=85076915023&partnerID=8YFLogxK

U2 - 10.1021/acs.jafc.9b06105

DO - 10.1021/acs.jafc.9b06105

M3 - Article

AN - SCOPUS:85076915023

VL - 68

SP - 10329

EP - 10335

JO - Journal of Agricultural and Food Chemistry

JF - Journal of Agricultural and Food Chemistry

SN - 0021-8561

IS - 38

ER -