Eighteen odorants were identified by applying aroma extract dilution analysis in the liquid fermentation broth of the edible mushroom Ischnoderma resinosum (P. Karst). Eight compounds with flavor dilution factors ≥16 were quantitated in a 16-day sample using stable isotope dilution assays. Odor activity values (OAV) revealed anise-smelling 4-methoxybenzaldehyde (OAV; 1639), vanilla-smelling 3,4-dimethoxybenzaldehyde (OAV; 51), and cherry-smelling benzaldehyde (OAV; 14) as key contributors to the pleasant “candy-like” odor of the fermentation broth. Odor simulation experiments revealed a mixture of five compounds in their natural concentrations mimicked the odor of a 16-day-old fermentation broth. A 30-day time course study was conducted to monitor the production of three odorants in the fungal fermentation broth, where it was revealed that both 3,4-dimethoxybenzaldehyde (10.7 ± 1.0 mg/kg) and benzaldehyde (4.5 ± 0.1 mg/kg) peaked on day 16, whereas 4-methoxybenzaldehyde peaked on day 24 (104.9 ± 4.9 mg/kg).

Employing isotope incubation studies, the biosynthetic pathway leading to a series of benzylic derivatives was elucidated in the fermentation broth of the edible mushroom Ischnoderma resinosum (P. Karst). Twenty-six hydroxy- and methoxy- benzylic derivatives were screened by gas chromatography–mass spectrometry (GC–MS) of which 13 were detected in the culture media. Results from the isotope incubation studies showed the transformation of both benzyl alcohol and benzoic acid into benzaldehyde. Benzaldehyde was then converted into 4-methoxybenzaldehyde via hydroxylation and subsequent methylation of the 4-C position. The resulting 4-methoxybenzaldehyde was then hydroxylated in the 3-C position followed by methylation into 3,4-dimethoxybenzaldehyde. Based on these findings, a novel metabolic scheme for the biosynthesis of benzylic derivatives in I. resinosum was proposed. The knowledge of the biosynthetic pathway was utilized to produce 4-hydroxy-3-methoxybenzaldehyde (vanillin) from 4-hydroxy-3-methoxybenzoic acid (vanillic acid). This is the first report to elucidate the biosynthetic pathway of benzyl derivatives and production of vanillin from I. resinosum.

Thirty-five odorants from Meehan's mint, Meehania cordata, were identified using solvent-assisted flavor evaporation (SAFE) and aroma extract dilution analysis (AEDA). Twelve compounds with flavor dilution factors ≥16 were quantitated using stable isotope dilution assays (SIDA). Odor activity values (OAVs) and sensory experiments revealed (−)-(E)-pinocarvyl acetate as a key impact odorant contributing to the plant's unique woody and minty odor. Odor simulation experiments revealed a mixture of 10 compounds, including (2E,6Z)-nona-2,6-dienal (OAV 48000), β-ionone (OAV 33000), (E)-pinocarvyl acetate (OAV 8600), 1-octen-3-one (OAV 2800), and linalool (OAV 990), successfully mimicked the plant odor when combined in their natural concentrations. Three stereoisomers of pinocarvyl acetate were identified including (−)-(E)-, (+)-(E)-, and (−)-(Z)-isomers. The (E) to (Z)-ratio was determined as 95.5% (E) and 0.5% (Z). The enantiomeric ratio of (−)-(E)-to (+)-(E)-was determined as 96% (−)-(E)-and 4% (+)-(E)-pinocarvyl acetate. This study established the basis for future investigations aimed at determining the odorant variability of individual genotypes from natural populations of M. cordata and other members of the Meehenia genus.

The fragrant bolete, Suillus punctipes (Peck) Singer, is an edible mushroom with a unique aroma reminiscent of mushroom and citrus peel with an undertone of apricot. Thirty-five odorants were identified using solvent-assisted flavor evaporation (SAFE) and aroma extract dilution analysis (AEDA). Fourteen odorants including those with flavor dilution (FD) factors ≥64 were quantitated using stable isotope dilution assays (SIDA). Some odorants with high OAVs included 1-octen-3-one (OAV 164368), 1octen-3-ol (OAV 3421), linalool (OAV 812), and nonanal (OAV 487). An odor simulation model was prepared closely matching the aroma of the mushroom. Omissions experiments revealed that 1-octen-3-one, 1-octen-3-ol, (2E)-oct-2-enal, linalool, δdodecalactone, and a mixture of three aldehydes, octanal, nonanal, and decanal, were essential odorants for the aroma profile. Enantiomeric ratios were determined for several odorants employing chiral chromatography. The results from this study lay the groundwork for future studies in the aroma chemistry of S. punctipes and other mushrooms from the Suillus genus.

No abstract

Fermentation dynamics and benzylic derivative production were evaluated in the fermentation broth of six different Ischnoderma resinosum (P. Karst) isolates over a period of 30 days to understand their potential applications in bioreactor optimization for natural flavor compound production. d -Glucose and d -fructose levels decreased from 20.4 ± 0.4 to 7.1 ± 1.4 g/L and 1.0 ± 0.1 to <0.1 g/L, respectively, in all fermentations. Isolate I 2 produced the highest concentration of ethanol (546. 4 ± 0.4 mg/L). l -Lactic acid production varied between 4.3 ± 0.6 and 3.7 ± 0.2 mg/L, whereas acetic acid concentrations decreased from 81.0 ± 3.3 to <40.0 mg/L. pH decreased from 4.9 ± 0.0 to 3.6 ± 0.4 at the end of 30 days in all fermentations. Isolate I 3 was the highest producer of benzaldehyde (BA) (12.0 ± 0.2 mg/kg) and 4-methoxybenzaldehyde (4-MBA) (239.6 ± 3.9 mg/kg), while isolate I 4 was the highest producer of 3,4-dimethoxybenzaldehyde (3,4-DMBA) (27.8 ± 0.2 mg/18 kg). Identification of isolate I 3 as a high BA and 4-MBA producer and isolate I 4 as a high 3,4-DMBA producer suggested differential benzylic derivative production among I. resinosum isolates. This study lays the foundation for future investigations evaluating additional I. resinosum isolates for benzylic derivative production as well as studies aimed at bioreactor optimization with potential commercial application.

An investigation to identify odorants responsible for a pleasant woody perfumelike aroma produced in the fermentation broth of the fungus Daldinia childiae (JD Rogers & YM Ju) was conducted. Thirty odorants were identified from 30-day-old fermentations employing solvent-assisted flavour evaporation (SAFE) and aroma extract dilution analysis (AEDA). Eleven odorants with flavour dilution (FD) factors ≥16 were quantitated using stable isotope dilution assays (SIDA), and odour activity values (OAV) determined. Odorants with the highest OAVs included guai-11-en-10-ol (woody, OAV 102689), 1-octen-3-one (mushroom, OAV 9025), sotolon (maple, OAV 458), and (2E)-non-2-enal (fatty, OAV 70). An odour simulation model formulated using odorants with OAV ≥ 1 closely matched the sensory attributes of natural D childiae fermentations. Guai-11-en-10-ol, a component of patchouli essential oil used widely in perfumery and cosmetics, was identified as the key impact odorant driving the pleasant woody perfume-like aroma in D childiae fermentations. The findings from this investigation lay the groundwork for future studies on D childiae as a source for the sustainable biotechnological production of guai-11-en-10-ol with potential applications in the flavour and fragrance industry.