| 1. |
- Niimi, Jun, et al.
(author)
-
Aroma and bacterial communities dramatically change with storage of fresh white truffle Tuber magnatum
- 2021
-
In: Lebensmittel-Wissenschaft + Technologie. - : Academic Press. - 0023-6438 .- 1096-1127. ; 151
-
Journal article (peer-reviewed)abstract
- White truffles are highly valuable, but the aroma is susceptible to change with storage. How volatile composition and microbiome of Tuber magnatum evolve by storage time is poorly understood. Changes in bacterial community and volatile compounds of T. magnatum fruiting bodies with storage time at 23 °C were investigated. Truffles (21 fruiting bodies) were collected from different sites in Italy, Hungary, and Croatia. Single fruiting bodies were subsampled at four time points (day (D)0, 3, 6, and 9). Gas chromatography-mass spectrometry and microbiome composition using PCR-high throughput sequencing were used to analyse the volatiles and bacterial communities, respectively. Spoilage compounds atypical of truffles increased with storage time. Likewise, bacterial communities changed with storage time; families belonging to Xanthobacteraceae dominated at D0 and gradually evolved to more Rhizobiaceae and Pseudomonadaceae by D3 and D6, and finally with more prominent Xanthomonadaceae and Burkholderiaceae at D9. Overall, storage time had increased the diversity of bacterial communities. The microbiome and volatile data were correlated using regularised canonical correlation analysis and determined correlations between 2-methylisoborneol and five bacterial OTUs. Potential candidate bacteria and their volatile metabolites can serve as markers for truffle spoilage. The results highlighted the mechanisms by which the degradation of expensive truffles occur.
|
|
| 2. |
- Niimi, Jun, et al.
(author)
-
Geographical-based variations in white truffle Tuber magnatum aroma is explained by quantitative differences in key volatile compounds
- 2021
-
In: New Phytologist. - : Blackwell Publishing Ltd. - 0028-646X .- 1469-8137. ; 230:4, s. 1623-1638
-
Journal article (peer-reviewed)abstract
- The factors that vary the aroma of Tuber magnatum fruiting bodies are poorly understood. The study determined the headspace aroma composition, sensory aroma profiles, maturity and bacterial communities from T. magnatum originating from Italy, Croatia, Hungary, and Serbia, and tested if truffle aroma is dependent on provenance and if fruiting body volatiles are explained by maturity and/or bacterial communities. Headspace volatile profiles were determined using gas chromatography–mass spectrometry–olfactometry (GC-MS-O) and aroma of fruiting body extracts were sensorially assessed. Fruiting body maturity was estimated through spore melanisation. Bacterial community was determined using 16S rRNA amplicon sequencing. Main odour active compounds were present in all truffles but varied in concentration. Aroma of truffle extracts were sensorially discriminated by sites. However, volatile profiles of individual fruiting bodies varied more within sites than across geographic area, while maturity level did not play a role. Bacterial communities varied highly and were partially explained by provenance. A few rare bacterial operational taxonomical units associated with a select few nonodour active volatile compounds. Specificities of the aroma of T. magnatum truffles are more likely to be linked to individual properties than provenance. Some constituents of bacteria may provide biomarkers of provenance and be linked to nonodour active volatiles. © 2021 The Authors
|
|
| 3. |
- Niimi, Jun, et al.
(author)
-
Odour active compounds determined in the headspace of yellow and black plum wines (Prunus domestica L.)
- 2020
-
In: Lebensmittel-Wissenschaft + Technologie. - : Academic Press. - 0023-6438 .- 1096-1127. ; 130
-
Journal article (peer-reviewed)abstract
- Odour active compounds (OACs) from the headspace of yellow and black plum wines (Prunus domestica L.) were analysed using gas chromatography-mass spectrometry-olfactometry (GC-MS-O). Olfactometry was conducted using aroma extract dilution assay, through varying split ratios during injection. A total of 18 OACs were determined in the wine headspace including esters, ketones, sulfur containing compounds, alcohols, a terpene, and phenolic compounds. Thirteen of volatile compounds differed significantly (p < 0.05) in concentration between plum wines. Unique OACs were also detected within the headspace that distinguished the wines, where 4-ethyl guaiacol was only detected in the yellow plum wine and diacetyl was only detected within the black plum wines. The remaining nine OACs were not significantly different from each other, suggesting their ubiquity in the plum wines. High flavour dilution (FD) values were determined for ethyl isobutyrate, ethyl 2-methyl butyrate, β-damascenone, and ethyl cinnamate. All compounds detected in the plum wines have been previously reported in grape wine and demonstrated the commonality of volatile constituents between plum and grape wine. However, the very high concentration of β-damascenone may strongly contribute to the overall aroma of the plum wines.
|
|
| 4. |
- Schenkel, D., et al.
(author)
-
Linking soil's volatilome to microbes and plant roots highlights the importance of microbes as emitters of belowground volatile signals
- 2019
-
In: Environmental Microbiology. - : Blackwell Publishing Ltd. - 1462-2912 .- 1462-2920. ; 21:9, s. 3313-3327
-
Journal article (peer-reviewed)abstract
- Plants and microbes release a plethora of volatiles that act as signals in plant–microbe interactions. Characterizing soil's volatilome and microbiome might shed light on the nature of relevant volatile signals and on their emitters. This hypothesis was tested by characterizing plant cover, soil's volatilome, nutrient content and microbiomes in three grasslands of the Swiss Jura Mountains. The fingerprints of soil's volatiles were generated by solid-phase micro-extraction gas chromatography/mass spectrometry, whereas high-throughput sequencing was used to create a snapshot of soil's microbial communities. A high similarity was observed in plant communities of two out of three sites, which was mirrored by the soil's volatilome. Multiple factor analysis evidenced a strong association among soil's volatilome, plant and microbial communities. The proportion of volatiles correlated to single bacterial and fungal taxa was higher than for plants. This suggests that those organisms might be major contributors to the volatilome of grassland soils. These findings illustrate that key volatiles in grassland soils might be emitted by a handful of organisms that include specific plants and microbes. Further work will be needed to unravel the structure of belowground volatiles and understand their implications for plant health and development.
|
|
