Formation of Diastereomeric Dihydromenthofurolactones by Cystostereum murrayi and Aroma Dilution Analysis Based on Dynamic Headspace Extraction

Abstract

Submerged cultures of the basidiomycota Cystostereum murrayi emit an intensive coconut-like, sweetish, and buttery smell. For identification of the key aroma compounds, an aroma dilution analysis using dynamic headspace was performed by adjusting the split ratio of the GC inlet system. Flavor dilution (FD) factors varied from 22 up to ≥218, whereby the largest class of compounds represented terpenoids, including two rare stereoisomers of 3,6-dimethyl-2,3,3a,4,5,7a-hexahydrobenzofuran (dill ether, ee ≥ 99.9). By means of nuclear magnetic resonance spectroscopy, the substances with the highest FD factors (29, 212, and 218) were identified as diastereomers of 3,6-dimethyl-3a,4,5,6,7,7a-hexayhydro-3H-1-benzofuran-2-one (dihydromenthofurolactone) and as its corresponding C3-unsaturated lactone. The latter two compounds have not been described for Cystostereum murrayi or for any other basidiomycota previously. Supplementation studies using 2-13C-d-glucose indicated that these lactones as well as the two stereoisomers of dill ether and other terpenoids were formed de novo by the fungus.

Production of an Anise- and Woodruff-like Aroma by Monokaryotic Strains of Pleurotus sapidus Grown on Citrus Side Streams

“…The biosynthesis of these monoterpene ethers as well as of wine lactone (39, FD 2048) by PSA has been reported by Trapp et al, who have shown that these benzofuranoid compounds were formed de novo by the fungus from D-glucose [14]. The biosynthesis of dill ether has also been reported for the fungus Cystostereum murrayi recently [31].…”

Wild Strawberry-like Flavor Produced by the Fungus Wolfiporia cocos─Identification of Character Impact Compounds by Aroma Dilution Analysis after Dynamic Headspace Extraction

“…As the investigated sample was solid, the DHS ADA technique, developed by Brescia et al for liquid samples, was first validated using a model system. 22 The split vents of TDU and CIS were sequentially combined to dilute the sample without the use of solvents. Linear correlations of the SR with the peak area of the EIC were shown for linalool, methyl anthranilate, and thymol (Figure 5A) as well as for (E)-, (Z)-linalool oxide, benzaldehyde, and geraniol (Supporting Information Figure S1A).…”

“…Apart from this, it is an easy, quick, solvent-free, and targeted tool for flavor analysis. 22 It allows for the simultaneous extraction of terpenes and aromatic compounds, for example, 2-aminobenzaldehyde.…”

“…Extracts were measured using a 7890B GC equipped with a 5977B MSD (Agilent Technologies) and a split/splitless liner with the same parameters as described for ADA. The following fragments were used as quantifiers: linalool (m/z 93), Enantiomeric excess of linalool was determined according to Brescia et al 22 Extraction was performed according to SIDA without addition of a deuterated standard using 85 g of the sample material, 100 mL of sat. NaCl solution, 100 mL of methanol, and 50 mL of pentane/diethyl ether (three times).…”

“…19−22 The present study elucidates a biotechnological process for the production of wild strawberry-like flavor by W. cocos from black currant pomace and its analysis using the recently developed ADA by DHS. 22 Further, stable isotope dilution analysis (SIDA) and standard addition were used to quantify the key aroma compounds and to finally recombine the produced aroma. Liquid−liquid extraction was performed using the following chemicals: methanol (UHPLC-grade) from J. T. Baker (Schwerte, Germany), NaCl and Na 2 SO 4 (≥99%) from Carl Roth GmbH & Co. KG, diethyl ether (99.9%) from Prolabo Chemikalien (Sion, Swiss), and pentane (99.9%) from Julius Hoesch GmbH & Co. KG (Duren, Germany).…”