Concentration Of Volatile Sulfur Compounds Research Articles

Effect of Antimicrobial Photodynamic Therapy on the Tongue Dorsum on Reducing Halitosis and the Duration of the Effect: A Randomized Clinical Trial.

Antimicrobial photodynamic therapy (PDT) is a treatment that is gaining popularity in modern clinical medicine. However, little is known about the effect of PDT alone on reducing oral halitosis and the duration of the effect. This trial examined the effect of PDT on the tongue dorsum on reducing oral halitosis and the duration of the effect. This study was approved by the Ethics Committee of Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, and Okayama University Hospital (CRB20-015), and it was registered in the Japan Registry of Clinical Trials (jRCTs061200060). Twenty-two participants were randomly assigned to two groups: an intervention group and control group. PDT was performed in the intervention group using red laser emission and methylene blue gel on the middle and posterior area of the tongue dorsum. The concentration of volatile sulfur compounds, bacterial count on the tongue dorsum, probing pocket depth, bleeding on probing, and simplified oral debris index score were determined before and 1 week after PDT. The Mann-Whitney U test was used to assess the significance of the differences in each parameter between the two groups. We found that the hydrogen sulfide concentration and bacterial count on the tongue dorsum were decreased in the intervention group, but there was no statistically significant difference between the two groups. These results indicated that performing only PDT on the tongue dorsum may not contribute to reducing halitosis.

Effect of dental chew on reducing dental plaque, dental calculus and halitosis in beagle dogs

Periodontosis is the most common clinical disease in adult dogs, which is mainly caused by plaque accumulation and seriously endangers the oral health of dogs and even cause kidney, myocardial, and liver problems in severe cases. The aim of this study was to determine the clinical efficacy of dental chew (Cature Brushing Treats product) with mechanical and chemical properties in beagles. The dogs in the experimental group were fed with a dental chew twice a day after meals; The control group had no treatment. Dental plaque was evaluated on the 14th day and 29th day, respectively. The concentration of volatile sulfur compounds (VSC) in the breath and dental calculus were also evaluated on the 29th day. The results showed that there was no significant difference in the indexes of dental plaque on the 14th day. While they had significantly reduced accumulation of plaque (37.63%), calculus (37.61%), and VSC concentration (81.08%) compared to when receiving no chew on the 29th day.

Release characteristics and risk assessment of volatile sulfur compounds in municipal wastewater treatment plants

In recent years, the malodorous gases generated by sewage treatment plants have gradually received widespread attention due to their sensory stimulation and health hazards. The emission concentration, sensory evaluation and health risk assessment of volatile sulfur compounds (VSCs) were all explored in two municipal wastewater treatment plants (WWTPs) with oxidation ditch and anaerobic/oxic treatment process, respectively. The VSCs concentration showed the highest amount in the primary treatment unit in both the two WWTPs (73.3% in Plant A and 93.0% in Plant B), while the H2S took the main role in the composition of VSCs. However, H2S took a larger percentage in Plant A (84.5% ∼ 87.0%) rather than Plant B (61.2% ∼ 83.5%), which may be due to the different operating conditions and sludge properties in different treatment process. Besides, H2S also gained the first rank in the sensory evaluation and health risk assessment, which may cause considerable sensory irritation and health risk to workers and surrounding residents. Furthermore, the influencing factor analyses of VSCs emission showed that the temperature of water and air, ORP of sludge made the greatest effect on VSCs release. This study provides theoretical and data support for the research of VSCs emission control in WWTPs.

Effect of sleeve gastrectomy on the levels of oral volatile sulfur compounds and halitosis-related bacteria

BackgroundThe association between sleeve gastrectomy and halitosis remains relatively unknown. Therefore, this study aimed to evaluate the effect of sleeve gastrectomy on halitosis and the oral bacterial species associated with halitosis in patients with obesity. MethodsThis was a prospective longitudinal cohort study that examined patients before and after sleeve gastrectomy and followed the patients at three time intervals (1, 3, and 6 months) after sleeve gastrectomy. Clinical periodontal measurements (plaque index [PI], gingival index [GI], and probing depth [PD]) were obtained. In addition, plaque samples were collected for quantification of the periodontopathogenic bacteria: Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Fusobacterium nucleatum using real-time quantitative polymerase chain reaction (qPCR). In addition, breath samples were collected to analyze the concentration of volatile sulfur compounds (VSCs), namely hydrogen sulfide (H2S), methyl mercaptan (CH3SH), and dimethyl sulfide (CH3SCH3), via portable gas chromatography (Oral Chroma™). ResultsOf the 43 patients initially included, 39 completed the study, with a mean age of 32.2 ± 10.4 years. For PI and GI repeated measurements one way analysis of variance showed a significant increase (p-value < 0.001 for both) one month after surgery, with mean values of 1.3 and 1.59, respectively, compared to the baseline. During the same period, the number of P. gingivalis increased, with a p-value = 0.04. Similarly, the levels of hydrogen sulfide (H2S) and methyl mercaptan (CH3SH) increased significantly in the first month after surgery (p-value = 0.02 and 0.01, respectively). ConclusionThis study demonstrated that sleeve gastrectomy may lead to increased halitosis one month post-surgery, attributed to elevated and P. gingivalis counts, contributing to the development of gingivitis in obese patients who underwent sleeve gastrectomy. This emphasizes the importance of including oral health professionals in the multidisciplinary team for the management of patients undergoing bariatric surgery

Effects of a novel dental chew on oral health outcomes, halitosis, and microbiota of adult dogs.

Halitosis in dogs is an initial indication of periodontitis, highlighting its significance as a vital marker for underlying problems. Moreover, the oral microbial population has a significant influence on periodontal disease. Measuring the oral microbiota may be used in addition to breath odor, dental plaque, and gingivitis scoring to assess the impact of dental chews on oral health. In this study, we aimed to determine the differences in breath odor, oral health outcomes, and oral microbiota of adult dogs consuming a novel dental chew compared with control dogs consuming only a diet. Twelve healthy adult female beagle dogs were used in a crossover design study. Treatments (n = 12/group) included: diet only (control) or the diet + a novel dental chew. Each day, one chew was provided 4h after mealtime. On days 1, 7, 14, 21, and 27, breath samples were analyzed for total volatile sulfur compound concentrations using a halimeter. On day 0 of each period, teeth were cleaned by a veterinary dentist blinded to treatments. Teeth were scored for plaque, calculus, and gingivitis by the same veterinary dentist on day 28 of each period. After scoring, subgingival and supragingival plaque samples were collected for microbiota analysis using Illumina MiSeq. All data were analyzed using SAS (version 9.4) using the Mixed Models procedure, with P < 0.05 being significant. Overall, the dental chews were well accepted. Dogs consuming the dental chews had lower calculus coverage, thickness, and scores, lower gingivitis scores, and less pocket bleeding than control dogs. Breath volatile sulfur compounds were lower in dogs consuming the dental chews. Bacterial alpha-diversity analysis demonstrated that control dogs had higher bacterial richness than dogs fed dental chews. Bacterial beta-diversity analysis demonstrated that samples clustered based on treatment. In subgingival and supragingival plaque, control dogs had higher relative abundances of potentially pathogenic bacteria (Pelistega, Desulfovibrio, Desulfomicrobium, Fretibacterium, Helcococcus, and Treponema) and lower relative abundances of genera associated with oral health (Neisseria, Actinomyces, and Corynebacterium). Our results suggest that the dental chew tested in this study may aid in reducing periodontal disease risk in dogs by beneficially shifting the microbiota population and inhabiting plaque buildup.

Real-time monitoring of ground-tire rubber microwave devulcanization with thermal and electrochemical sensors

Devulcanizing ground-tire rubber (GTR) properly requires the removal of the sulphur linkages that crosslink the polymer. The volatile sulphur compounds (VSCs) released during the process must be extracted from the reactor to avoid any chemical recombination, and the sulphur gas concentrations conveniently sensed during the extraction, along with a thermal sensoring of the payload, can be used to monitor the whole devulcanization process. In this contribution, a modified conventional microwave oven was used to devulcanize the GTR. The microwave-processed GTR was evaluated by determining the values of its mass loss (ML), soluble fraction (sol fraction), and the variation of its electric permittivity. Results show a direct relationship between the energy delivered, sol fraction, the VSCs concentrations, the ML, and the permittivity values. Thus, this paper demonstrates that monitoring the VSCs can provide a reliable indication of ML and, consequently, devulcanization evolution even at non-uniform temperature conditions.

Integrative proteomic-transcriptomic analysis revealed the lifestyles of Lactobacillus paracasei H4-11 and Kluyveromyces marxianus L1-1 under co-cultivation conditions

Compared with the rice-acid soup inoculated with single starter, the synergistically intensified rice-acid soup inoculated with Lactobacillus paracasei H4-11 (L. paracasei H4-11) and Kluyveromyces marxianus L1-1 (K. marxianus L1-1) contained more flavor compounds. Organic acids mainly included L-lactic acid and the main volatile flavor component was ethyl acetate. Moreover, the signal intensity of astringency and bitterness and the total concentration of volatile sulfur compounds were reduced. The combined analysis results of RNA sequencing (RNA-seq) technology and 4D label-free quantitative (4D LFQ) proteomics explained the flavor formation pathways in rice-acid soup inoculated with L. paracasei H4-11 and K. marxianus L1-1. In L. paracasei H4-11, L-lactate dehydrogenase, phosphoglucomutase, acetate kinase, alcohol dehydrogenase and acetyl-CoA were up-regulated and D-lactate dehydrogenase and N-Acetyltransferase were down-regulated. In K. marxianus L1-1, Acetyl-CoA, acetaldehyde dehydrogenase, acyl-coenzyme A, N-acetyltransferase, and L-lactate dehydrogenase were up-regulated and hexokinase, alcohol dehydrogenase, and alcohol O-acetyltransferase were down-regulated. The above up-regulation and down-regulation synergistically promoted the formation of characteristic flavor compounds (mainly L-lactic acid and ethyl acetate). Enzyme-linked immunoassay (ELISA) and parallel reaction monitoring (PRM) quantitative analysis respectively verified that 5 key metabolic enzymes and 27 proteins in L. paracasei H4-11 and K. marxianus L1-1 were associated with the characteristic flavor of rice-acid soup, as confirmed by the quantitative results of 4D LFQ.

Improvement of halitosis by probiotic bacterium Weissella cibaria CMU: A randomized controlled trial.

Several in vitro and in vivo studies have evaluated the effect of probiotics on oral health; however, human clinical studies are still limited. Therefore, this study aimed to examine the effects of Weissella cibaria Chonnam Medical University (CMU)-containing tablets on halitosis. This randomized, double-blinded, placebo-controlled study included 100 adults with halitosis (age, 20-70 years). The participants were randomly assigned to the test group (n = 50) and control group (n = 50). One tablet [1 × 108 colony forming units (CFU)/tablet] was to be taken each day over 8 weeks. The concentrations of volatile sulfur compounds (VSCs), bad breath improvement scores, and oral colonization of W. cibaria were measured. Psychosocial indicators including depression, self-esteem, oral health-related quality of life, and subjective oral health status were evaluated. Most variables were assessed at baseline, 4, and 8 weeks, and W. cibaria number and safety variables were assessed at baseline and 8 weeks. Intergroup comparisons were carried out using Student's t-test, Chi-square test, or Fisher's exact test on per-protocol analysis. Intragroup differences before and after intake were analyzed using the linear mixed-effect model (LMM). Per-protocol analysis was carried out in the test group (n = 45) and control group (n = 46). Total VSC was significantly lower in the probiotics group than in the placebo group at baseline (week 0, p = 0.046) and at 8 weeks (p = 0.017). The sum of hydrogen sulfide and methyl mercaptan did not differ significantly between the groups at baseline; however, it was significantly lower in the probiotics group than in the placebo group at week 8 (p = 0.012). Bad breath improvement (BBI) scores were significantly reduced at week 8 (p = 0.006) in the probiotics group. Statistically significant intergroup differences were observed for changes in the level of W. cibaria at week 8 (p < 0.001). Psychological indicators significantly improved from baseline to week 8 in the probiotics group. No safety issues were observed in either group. The levels of W. cibaria was higher in patients with halitosis using W. cibaria CMU-containing tablets. The subjective degree of bad breath and psychological indicators were improved in patients with halitosis using W. cibaria CMU-containing tablets.

Accuracy of two methods to detect the presence of halitosis: the volatile sulfur compounds concentration in the mouth air and the information from a close person.

This study aimed to analyze the accuracy of two methods for detecting halitosis, the organoleptic assessment by a trained professional (OA) with volatile sulfur compounds (VSC) measurement via Halimeter® (Interscan Corporation) and information obtained from a close person (ICP). Participants were patients and companions who visited a university hospital over one year period to perform digestive endoscopy. A total of 138 participants were included in the VSC test, whose 115 were also included in the ICP test. ROC curves were constructed to establish the best VSC cut-off points. The prevalence of halitosis was 12% (95%CI: 7% to 18%) and 9% (95%CI 3% to 14%) for the OA and ICP, respectively. At the cut-off point >80 parts per billion (ppb) VSC, the prevalence of halitosis was 18% (95%CI: 12% to 25%). At the cut-off point >65 ppb VSC, sensitivity and specificity were 94% and 76%, respectively. At the cut-off point >140 ppb, sensitivity was 47% and specificity 96%. For the ICP, sensitivity was 14% and specificity 92%. VSC presents high sensitivity at the cut-off point of >65 ppb and high specificity at the cut-off point of >140 ppb. ICP had high specificity, but low sensitivity. The OA can express either occasional or chronic bad breath, whereas the ICP can be a potential instrument to detect chronic halitosis.

Evaluation of efficacy of 0.1% of chlorine dioxide mouthwash against oral malodor – A pilot study

BACKGROUND: Oral malodor, also known as halitosis or bad breath can be defined as an offensive odor that emerges from the oral cavity and can be easily detected by others. The etiology of halitosis is multifactorial and can include several intra- and extraoral factors such as gingivitis, periodontitis, chronic sinusitis, nasal inflammation, diabetes mellitus, lung carcinoma, liver insufficiency, cirrhosis, uremia, trimethylaminuria, and postnasal drip. Chlorine dioxide associated with chlorite anion results in the oxidative consumption of amino acids such as cysteine and methionine, which are precursors of volatile sulfur compounds (VSC). Thus, it can reduce the concentrations of VSCs which help in the reduction of oral malodor. Due to the lesser availability of literature to prove the effectiveness of this chlorine dioxide formula, this study is conducted to evaluate the inhibiting effect of commercially available chlorine dioxide-containing mouthwash – FRESHCLOR to combat oral malodor in patients.MATERIALS AND METHODS: The study was conducted among the patients reporting at the outpatient department of periodontics who visited with the chief complaint of bad breath and bleeding gums at KAHER'S VK Institute of Dental Sciences, Belagavi. Patients were selected according to inclusion criteria and divided into test and control groups. Post scaling Freshclor mouthwash was distributed to all test group participants. The organoleptic ratings for halitosis, gingival index (given by Loe H and Silness J, 1963), and plaque index (given by Loe H and Silness J, 1964) were recorded at baseline and 2 weeks for the group.RESULTS: There was a statistically significant reduction in halitosis with a reduction of gingival and plaque indices at 2 weeks from baseline in the test group.CONCLUSION: With the results, it can be concluded that chlorine dioxide-containing mouthwash – freshclor is effective in reducing halitosis.

Volatile Sulfur Compound in Pinot noir Wines Affected by Vineyard Irrigation, Tillage, and Nitrogen Supplementation

The effects of vineyard nitrogen fertilization, tilling, and irrigation on the contents of volatile sulfur compounds in Pinot noir wines were investigated in this study. Wines were made from two field blocks of twelve combinations of irrigation (dry or irrigated), tillage (tilled or not tilled), and fertilization (none, foliar nitrogen supplementation or soil applied nitrogen) from three vintages of Vitis vinifera cv. Pinot noir. The concentrations of volatile sulfur compounds were quantified using solid-phase micro-extraction and gas chromatography/ pulse flame photometric detection (HS-SPME-GC/PFPD). Multivariate analysis of variance (MANOVA) showed that vintage year, irrigation, and nitrogen can affect volatile sulfur compounds (p&lt;0.01). Foliar nitrogen supplementation or soil nitrogen application significantly increased the contents of H2S (p&lt;0.01) and methanethiol (MeSH) (p&lt;0.01) in Pinot noir wines. Irrigation treatment yielded higher H2S and MeSH than non-irrigation treatment, and with tillage treatments also yielded higher H2S and MeSH. ANOVA demonstrated the interaction factor (irrigation×nitrogen) had significant impact on concentration of H2S and MeSH in wines. The combination of irrigation and soil nitrogen supplement had the highest amount of both H2S and MeSH. Dimethyl sulfide (DMS), methionol, methyl thioacetate (MeSOAc), and ethyl thioacetate (EtSOAc) were mainly affected by vintage.

Effect of face masks on salivary parameters and halitosis: Randomized controlled crossover trial.

Face masking is associated with self-perceived dry mouth and halitosis. Aim of the study was to measure the effect of different face masks on salivary parameters and halitosis. The randomized controlled crossover clinical trial with four periods included 40 oral healthy participants using different face masks (cloth mask, surgical mask, filtering facepiece 2 [FFP2] mask) or no mask (control) for 4h in random order. Unstimulated salivary flow rate (primary outcome) and stimulated salivary flow rate, salivary pH and buffer capacity of stimulated and unstimulated saliva (secondary outcomes, blinded), and volatile sulfur compounds (secondary outcome) were measured before and after the 4-h periods. Statistical analysis was performed by repeated measures ANOVA (p < 0.05). Of 40 randomized participants, 39 completed the study. Unstimulated salivary flow rate prior to face masking amounted to 0.6 ± 0.3ml/min. Face masking had no significant effect on unstimulated salivary flow (p=0.550). Face masking had also no significant effect on the other salivary parameters (p ≥ 0.518). The concentration of volatile sulfur compounds (VSC) prior to face masking amounted to 157.3 ± 59.7ppb. After face masking, the concentration of VSC increased slightly, but not significantly (p=0.055): 168.1 ± 76.3ppb (control), 199.3 ± 132.7ppb (cloth masks), 188.5 ± 101.1ppb (surgical masks), and 189.7 ± 90.1ppb (FFP2 masks). Four hours of face masking did not change the salivary flow rate, pH, and buffer capacity, and had no significant effect on VSC's levels. Wearing face masks does not seem to result in measurable side-effects on salivary parameters such as a reduced salivary flow rate or VSC's levels. The protocol was prospectively registered at ClinicalTrials.gov (NCT04914208) on June 4, 2021.

Response Surface Methodology Approach to Evaluate the Effect of Transition Metals and Oxygen on Photo-Degradation of Methionine in a Model Wine System Containing Riboflavin.

A Box-Behnken experimental design was implemented in model wine (MW) to clarify the impact of copper, iron, and oxygen in the photo-degradation of riboflavin (RF) and methionine (Met) by means of response surface methodology (RSM). Analogous experiments were undertaken in MW containing caffeic acid or catechin. The results evidenced the impact of copper, iron, and oxygen in the photo-induced reaction between RF and Met. In particular, considering a number of volatile sulfur compounds (VSCs) that act as markers of light-struck taste (LST), both transition metals can favor VSC formation, which was shown for the first time for iron. Oxygen in combination can also affect the concentration of VSCs, and a lower content of VSCs was revealed in the presence of phenols, especially caffeic acid. The perception of "cabbage" sensory character indicative of LST can be related to the transition metals as well as to the different phenols, with potentially strong prevention by phenolic acids.

Probiotics for caries prevention during orthodontic treatment

Relevance. The article analyzes the literature data on the use of probiotics for caries prevention. It presents clinical study results of the effectiveness of the DentoBLIS probiotic with Str. Salivarius M18 strain and vitamin D during orthodontic treatment in adolescents. Materials and methods. We conducted an open single-centre comparative study on the DentoBLIS one-month administration to 40 adolescents with fixed orthodontic appliances and dental caries. Results. The DentoBLIS one-month use demonstrated a decrease in the oral hygiene index by 16.45%, braces hygiene index – by 26.58%, the Muehlemann-Cowell index reduction by 16.67%, and an anti-halitosis effect – decrease in halitosis severity according to the VAS by 24.92%, according to the concentration of volatile sulfur compounds (VSCs) by 34.48%. DentoBLIS affects the saliva biochemical parameters, reflecting the microbiota condition: a significant increase in pH from 6.88 ± 0.04 to 6.95 ± 0.04, a decrease in saliva protein level from 5.01 ± 0.48 to 3.68 ± 0.44 g/l, decrease in glucose level from 0.45 ± 0.07 to 0.29 ± 0.02 mmol /l and GOT from 10.87 ± 1.18 to 7.73 ± 0.94 U/l. Conclusion. The DentoBLIS probiotic reduces plaque formation, gingival bleeding and halitosis severity in adolescents with dental caries during orthodontic treatment. Biochemical analysis revealed changes in some parameters of mixed saliva after the DentoBLIS use, which indicates a positive effect of the probiotic on the oral microbiota.

Evaluation of oenological tannins for preventing the light-struck taste

The light-struck taste (LST) is a fault occurring in white and rosé wines associated to the formation of volatile sulfur compounds (VSCs) due to the reactions between riboflavin (RF) and methionine (Met). We investigated the possible preventing effect of 15 commercial tannins of different origin in model wine added with RF and Met, under oxic and anoxic conditions, and submitted to standardized light-exposure. All the tannins limited the degradation of Met in comparison to the tannin-free samples. Lower concentrations of VSCs were found in presence of tannins even under anoxia, condition favouring their formation. The sniffing trials evidenced the minor perception of cooked cabbage note with added tannins. The multivariate analysis showed the presence of flavan-3-ols was related to the formation of DMDS and DMTS, while tannic acid was related to MeSH, both the behaviors occurring under oxic condition. The study highlighted the ability of tannins to prevent the LST.

109 Effects of a Novel Dental Chew on the Oral Health Outcomes and Malodor of Adult Dogs

Abstract Periodontal disease is a common oral health condition occurring in adult dogs, yet it is a preventable disease. The objective of this study was to evaluate the efficacy of a novel dental chew in adult dogs. All animal care and experimental procedures were approved by the University of Illinois Institutional Animal Care and Use Committee prior to experimentation. Twelve female beagles (mean age = 3.50 yr; mean BW = 8.77 kg) were used in a crossover design consisting of two 28-d periods. All dogs consumed the same commercial kibble diet throughout the study. Control dogs were offered only diet, while the treatment group received the diet plus a daily dental chew (Authority Dental Chew Orashield system formula containing sodium hexametaphosphate and texture) 4 h after their meal. On d0 of each period, teeth were cleaned by a veterinary dentist. Teeth were then scored for plaque, calculus, and gingivitis by the same veterinary dentist that was blinded to treatments on d28 of each period. Breath samples were measured for breath halitosis (volatile sulfur compounds) using a halimeter on d1, 7, 14, 21, and 27 of each period. All tooth scoring data were analyzed using the Mixed Models procedures of SAS. Halimeter data were analyzed using repeated measures using Mixed Models procedures. Oral calculus coverage and thickness were less (P&amp;lt; 0.05) in dogs consuming the novel chew than control dogs, while plaque was not different among groups. Gingivitis scores and gingival bleeding were also less (P&amp;lt; 0.05) in dogs consuming the novel chew compared with control dogs. Breath volatile sulfur compound concentrations were reduced (P&amp;lt; 0.05) in dogs consuming the novel chew than control dogs. Our results suggest that the novel dental chew tested in the study may aid in reducing the risk of periodontal disease in dogs.

The variation of odor characteristics of wastewater sludge treated by advanced anaerobic digestion (AAD) and the contribution pattern of key odorants

Identification of the odor characteristics of wastewater sludge is important in the evaluation of sludge quality and disposal options considering that sludge odor nuisance may cause major environmental issues. In this study, raw sludge and sludge cake were collected from five WWTPs applied advanced anaerobic digestion (AAD) sludge treatment process to clarify the variation of odor characteristics using sensory analysis and instrumental analysis. The electronic nose, gas chromatography-ion mobility spectrometry (GC-IMS) and gas chromatography-triple quadrupole tandem mass spectrometry (GC–MS/MS) were used to profile and identify the chemical composition of key odorants. A total of 20 odorants were identified and quantified, including 6 groups of chemicals, among which volatile sulfur compounds (VSCs), indole, 3-methylindole and geosmin were identified as key odorants. The odor of the dewatered digested sludge was improved by means of changing the odor character from fecal/sulfide to earthy odor due to the reduction in VSCs concentration. The AAD and subsequent dewatering process resulted in effective removal of VSCs, which are important constituents that impact the sludge odor characteristics through synergistic effect on fecal odorants and masking effect on earthy odorants. Moreover, due to the variation of sludge quality after AAD treatment, the emission capacity of indole, 3-methylindole, and other volatiles increased, which could not be neglected for the formation of unique sludge odor.

New Insights into the Origin of Volatile Sulfur Compounds during Wine Fermentation and Their Evolution during Aging

Volatile sulfur compounds (VSCs) are associated with unpleasant reductive aromas and are responsible for an important reduction in wine quality, causing major economic losses. Understanding the origin of these compounds in wine remains a challenge, as their formation and further evolution during winemaking can involve both chemical and biological reactions. Comparing the VSCs profile (i) of fermenting synthetic grape juices supplemented with a selected VSC (eight compounds tested) and incubated in presence or absence of yeast, and (ii) during storage of wines under an accelerated aging procedure, allowed us to elucidate the chemical and metabolic connections between VSCs during fermentation and aging. Yeast metabolism, through the Ehrlich pathway and acetylation reactions, makes an important contribution to the formation of compounds such as methionol, 3-methylthiopropionate, 3-methylthiopropylacetate, 3-mercaptopropanol, 2-mercaptoethanol and thioesters. By contrast, chemical reactions are responsible for interconversions between thiols and disulfides, the formation of thiols from thioesters or, more surprisingly, the formation of ethylthiopropanol from methionol during fermentation. During aging, variations in heavy VSC concentrations, such as an increase in 3-methylthiopropylacetate and a decrease in ethyl-3-methylthiopropionate formation, were evidenced. Overall, this study highlights that it is essential to consider both yeast metabolism and the high chemical reactivity of VSCs to understand their formation and evolution during winemaking.

Flavor deterioration of Mandarin juice during storage by MDGC-MS/O and GC-MS/PFPD

Commercial mandarin juice often exhibits flavor deterioration during storage. The changes in volatile flavor profiles were investigated in mandarin juice stored under three different temperature conditions (4 °C, 25 °C, and 40 °C). The application of multidimensional gas chromatography-mass spectrometry/olfactometry (MDGC-MS/O) coupled with aroma extract dilution analysis (AEDA) identified 31 odorants in stored mandarin juice, including seven off-flavor contributing compounds: methanethiol (unpleasant, repulsive), dimethyl sulfide (sulfur, cabbage), methional (cooked potato), p-cymene (solventy), 4-vinylguaiacol (medicine), terpinen-4-ol (wood), and α-terpineol (floral, mint). 4-Vinylguaiacol was also identified in mandarin juice for the first time. In addition, 64 volatile compounds determined by GC-MS/pulsed flame photometric detector (GC-MS/PFPD) were classified as alcohols, terpenes, volatile sulfur compounds (VSCs), aldehydes, esters, ketones, and phenols. Volatile compound differences were observed in mandarin juice under different storage conditions by heat-map generation and principal component analysis (PCA). The results revealed that high-temperature storage led to a rapid increase in the concentration of total alcohols and VSCs. Furthermore, the flavor deterioration markers α-terpineol and dimethyl sulfide were identified based on off-flavor contribution and variable importance in projection (VIP) (score >1) values in the PLS-DA model. These two compounds are valuable for marker-assisted flavor deterioration analysis in mandarin juice during storage.

Efficacy of a Zinc Lactate Mouthwash and Tongue Scraping in the Reduction of Intra-Oral Halitosis: A Single-blind, Controlled, Crossover Clinical Trial-A Pilot Study.

Intra-oral halitosis is defined as an unpleasant odor that comes out of the mouth. The aim of this study was to investigate the effect of zinc lactate mouthwash and tongue scraping on intra-oral halitosis. The study was conducted on 60 volunteers that were divided into two groups and fol-lowed two types of 14-day oral hygiene protocols on a cross-over basis after a 7-day wash-out period. One protocol was based on tooth brushing only, while the other was based on additional mouth rinsing with a zinc lactate product and tongue scraping. Morning mouth breath was as-sessed organoleptic and by volatile sulfur compound concentrations. The highest mean organo-leptic and volatile sulfur compound measurement values were found in the tooth brushing without mouth washing and tongue scraping oral hygiene protocol (p < 0.05). The zinc lactate mouthwash combined with tongue scraping appears to be an important hygienic procedure to reduce breath odor.