Abstract:Dimethyl trisulfide (DMTS) develops in wine during storage, creating an unpleasant aroma. However, the mechanisms of DMTS formation during the wine-making process are poorly understood. We attempted to identify the factors that affect DMTS development during storage. We found that the death of yeast cells, followed by the leakage of their cell contents into the must, enhanced DMTS formation, but this effect varied between grape cultivars. Oxidation of the must and insufficient clarification of the grape juice … Show more
“…Methionine can be found in cocoa beans, meaning that an enzymatic formation within the bean is possible. The exclusive presence of dimethyl trisulfide in the traditionally fermented sample might be related to the lysis of yeast cells, resulting in the release of sulfurous amino acids as precursors for the dimethyl trisulfide formation, as recently demonstrated for wines with elevated amounts of this odorant …”
Section: Resultsmentioning
confidence: 75%
“…The exclusive presence of dimethyl trisulfide in the traditionally fermented sample might be related to the lysis of yeast cells, resulting in the release of sulfurous amino acids as precursors for the dimethyl trisulfide formation, as recently demonstrated for wines with elevated amounts of this odorant. 45 Odor Activity Values (OAVs) and Orthonasal Sensory Profiles. The calculated OAVs are shown in Table 3.…”
Section: Journal Of Agricultural and Food Chemistrymentioning
The aroma properties of cocoa nibs obtained by applying a novel postharvest treatment were investigated using methods of the molecular sensory science approach, i.e., solvent extraction and solvent-assisted flavor evaporation, aroma extract dilution analysis (AEDA), stable isotope dilution analysis, calculation of odor activity values (OAVs), and orthonasal sensory evaluation; those properties were then compared to the unfermented and dried raw material and a traditionally fermented sample of the same harvest. For the treatment, unfermented and dried cocoa nibs were, first, rehydrated with lactic acid and ethanol solution to adjust the pH value to 5.1 and, second, incubated under aerobic conditions for 72 h at 45°C and subsequently dried. This treatment was used to induce enzymatic reactions within the cotyledon matrix, which also occur inside the bean during microbial fermentation of the surrounding fruit pulp. The results of the AEDA showed that many of the key aroma compounds found in fermented and dried cocoa increased during the incubation treatment. Especially some "fruity" esters were found with an equal or even higher flavor dilution (FD) factor in the incubated sample compared to the fermented sample, whereas the fermented sample showed high FD factors for "pungent, sour" and "sweaty" acids, such as acetic acid and 2and 3-methylbutanoic acids. The quantitative data and calculated OAVs for the samples supported the findings of the AEDA, underlining the potential of this approach as a controllable and reproducible alternative postharvest treatment.
“…Methionine can be found in cocoa beans, meaning that an enzymatic formation within the bean is possible. The exclusive presence of dimethyl trisulfide in the traditionally fermented sample might be related to the lysis of yeast cells, resulting in the release of sulfurous amino acids as precursors for the dimethyl trisulfide formation, as recently demonstrated for wines with elevated amounts of this odorant …”
Section: Resultsmentioning
confidence: 75%
“…The exclusive presence of dimethyl trisulfide in the traditionally fermented sample might be related to the lysis of yeast cells, resulting in the release of sulfurous amino acids as precursors for the dimethyl trisulfide formation, as recently demonstrated for wines with elevated amounts of this odorant. 45 Odor Activity Values (OAVs) and Orthonasal Sensory Profiles. The calculated OAVs are shown in Table 3.…”
Section: Journal Of Agricultural and Food Chemistrymentioning
The aroma properties of cocoa nibs obtained by applying a novel postharvest treatment were investigated using methods of the molecular sensory science approach, i.e., solvent extraction and solvent-assisted flavor evaporation, aroma extract dilution analysis (AEDA), stable isotope dilution analysis, calculation of odor activity values (OAVs), and orthonasal sensory evaluation; those properties were then compared to the unfermented and dried raw material and a traditionally fermented sample of the same harvest. For the treatment, unfermented and dried cocoa nibs were, first, rehydrated with lactic acid and ethanol solution to adjust the pH value to 5.1 and, second, incubated under aerobic conditions for 72 h at 45°C and subsequently dried. This treatment was used to induce enzymatic reactions within the cotyledon matrix, which also occur inside the bean during microbial fermentation of the surrounding fruit pulp. The results of the AEDA showed that many of the key aroma compounds found in fermented and dried cocoa increased during the incubation treatment. Especially some "fruity" esters were found with an equal or even higher flavor dilution (FD) factor in the incubated sample compared to the fermented sample, whereas the fermented sample showed high FD factors for "pungent, sour" and "sweaty" acids, such as acetic acid and 2and 3-methylbutanoic acids. The quantitative data and calculated OAVs for the samples supported the findings of the AEDA, underlining the potential of this approach as a controllable and reproducible alternative postharvest treatment.
“…Then, Pilkington and colleagues observed the presence of cysteinyl and glutathionyl polysulfanes in Saccharomyces cerevisiae for the first time [48]. Therefore, the increase of polysulfane concentrations in wine can be expected due to yeast autolysis, as was shown for dimethyl trisulfide (DMTS) (Me-S 3 -Me) [47]. Studies of polysulfane formation in yeast cells are currently in progress.…”
Reactive compounds with one or more sulfane sulfur atoms can be an important source of reductive off-odors in wine. These substances contain labile sulfur, which can participate in microbiological (enzymatic) and chemical transformations (including in the post-bottling period), releasing malodorous hydrogen sulfide (H2S) and its derivatives (MeSH, EtSH, etc.). The following sulfane sulfur compounds were considered in this review as important precursors in the wine chemistry of reductive aromas: elemental sulfur (S8), persulfides (R-S-S-H), polysulfanes (R-Sn-R(′)), polythionates (−O3S-Sn-SO3−), thiosulfate (S2O32−) and derivatives of (poly)sulfane monosulfonic acids (R-Sn-SO3H). This review discusses the formation of these compounds, their reactivity and chemical transformations in wine, including reactions of nucleophilic substitution. In particular, the reactions of thiolysis, thiosulfatolysis and sulfitolysis of sulfane sulfur compounds are described, which lead in the end to reductive aroma compounds. In this way, the review attempts to shed light on some of the mysteries in the field of sulfur chemistry in wine and the reappearance of reductive off-odors after bottling.
“…Recently, sake yeast with decreased DMTS-P1 productivity was developed 4 . DMTS is also involved in the off-flavour of beer 5 , whisky 6 , and wine 7 .Figure 11,3-Dimethyltrisulfane (DMTS) and ethyl hexanoate (EH).…”
Gold (Au) nanoparticles (NPs) supported on SiO2 (Au/SiO2) were prepared by a practical impregnation method and applied as an adsorbent for 1,3-dimethyltrisulfane (DMTS), which is responsible for an unpleasant odour in drinks, especially Japanese sake. Compared with a conventional adsorbent, activated carbon, Au/SiO2 selectively reduced the DMTS concentration in Japanese sake without decreasing the concentrations of other aromatic components. DFT calculations revealed that the selective adsorption of DMTS occurred through the formation of a stable intermediate. The size of the supported Au NPs was controlled by the preparation conditions and determined from TEM observations and XRD measurements, and the size was ranged from 2.4 nm to 30 nm. Au/SiO2 having Au NPs with a diameter of 2.4 nm adsorbed DMTS the most efficiently. Smaller Au NPs showed better DMTS adsorption capabilities because larger amounts of Au atoms were exposed on their surfaces in the size range of this study. Langmuir-type monolayer adsorption and one-to-one binding of Au–S are proposed to occur based on an adsorption isotherm experiment. Even though significant differences of the fruity aroma score were not observed in the sensory evaluation between Au/SiO2 and activated carbon for this less aromatic Japanese sake, Au/SiO2 selectively decreased the DMTS concentration in the instrumental analysis.
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