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32 result(s) for "odor contribution"
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Predictive Models of Odor Contribution and Thresholds for Volatiles in Identification of Novel Crop Aroma Compounds
Background/Objectives: Aroma is a key determinant of crop quality and consumer acceptance, and aroma contribution and odor threshold are critical attributes for the identification of aroma compounds. Because the experimental determination of aroma contribution and odor thresholds is time-consuming and complex, most volatiles lack contribution and/or threshold data. Methods: We compiled odor thresholds for 716 volatile compounds and 31,459 aroma contribution records, and trained machine-learning models that took molecular fingerprints and physicochemical descriptors (e.g., molecular weight, logP, TPSA) as inputs to predict aroma contribution and odor threshold. We evaluated multiple fingerprint–model combinations, optimized hyperparameters via 5-fold cross-validation on the training set, and assessed the best models on a held-out validation set. Results: The ECFP6–GBDT combination performed best for predicting aroma contribution (macro-F1 = 0.732; weighted-F1 = 0.912). The ECFP4–GBDT model performed best for predicting odor thresholds (R2 = 0.94; RMSE = 0.44). Applying the models to volatiles in passion fruit juice identified 2-phenylethyl acetate as a potential new contributor to passion fruit aroma, whereas menthyl acetate likely exerted a negative influence; both findings were confirmed by serial dilution and sensory evaluation. The developed models provided both a GUI and a CLI, were easy to use, and supported straightforward upgrades by retraining with user-provided data. Conclusions: This work provided a methodological foundation for identifying crop aroma compounds and supported the genetic improvement of aroma traits.
Emission Characteristics of Odorous Compounds from a Swine Farm on Jeju Island, Korea
This study investigated 26 malodorous substances emitted from a swine farm on Jeju Island, South Korea, to discern their specific emission characteristics and potential implications for workers’ health and environmental management. A detailed analysis of emissions from livestock buildings, the compost facility, and the manure storage tank was conducted. Accurate quantification involved rigorous collection methods measuring concentrations of NH3, hydrogen sulfide (H2S), trimethylamine (TMA), aldehyde compounds, volatile organic compounds (VOCs), volatile fatty acids (VFAs), p-cresol, indole, and skatole. High concentrations of NH3 and H2S, particularly in the manure storage tank, raised concerns about the health of workers. TMA levels were notably elevated in the livestock building, whereas aldehydes and VOCs remained within limits. VFAs were prevalent in the livestock building, with p-cresol, indole, and skatole in the manure storage tank. Distinct emission profiles across farm facilities highlight the need for tailored odor management strategies, ensuring worker well-being and effective environmental practices. These findings offer valuable insights for implementing targeted mitigation measures in similar agricultural settings.
Odor detection threshold, but not odor identification, is impaired in children with autism
The aim of our study was to examine odor detection thresholds and odor identification in autistic subjects. Thirty-five patients with Asperger’s syndrome and high functioning autism (mean age 10.8 ± 3.6 years; 31 boys) were compared with 35 healthy control subjects (mean age 10.4 ± 2.4 years; 28 boys). There were no significant differences between groups with regard to mean age ( p  = 0.598) and gender proportion ( p  = 0.324). Olfactory testing used the Sniffin’ Sticks test (threshold and identification parts only). Participants with Asperger’s syndrome and high functioning autism, in comparison with healthy controls, were significantly impaired relative to odor detection thresholds (6.3 ± 3.1 vs. 7.9 ± 2.0; p  = 0.025). Autistic participants were significantly better in correctly identifying the odor of an orange (94 vs. 63%; p  < 0.05) and significantly worse at correctly identifying the odor of cloves (40 vs. 74%; p  < 0.05). With regard to identification of fourteen other substances, there were no significant differences. There was no significant difference between autistic and control subjects on the total score of olfactory identification ( p  = 0.799). Odor identification ability (as expressed by this total score) correlated significantly with age in the control group ( p  = 0.049), but not in the autism group ( p  = 0.103). We found impaired odor detection and almost normal odor identification in children with autism. Implications for further research are discussed.
The use of an in-vitro batch fermentation (human colon) model for investigating mechanisms of TMA production from choline, l-carnitine and related precursors by the human gut microbiota
Purpose Plasma trimethylamine-N-oxide (TMAO) levels have been shown to correlate with increased risk of metabolic diseases including cardiovascular diseases. TMAO exposure predominantly occurs as a consequence of gut microbiota-dependent trimethylamine (TMA) production from dietary substrates including choline, carnitine and betaine, which is then converted to TMAO in the liver. Reducing microbial TMA production is likely to be the most effective and sustainable approach to overcoming TMAO burden in humans. Current models for studying microbial TMA production have numerous weaknesses including the cost and length of human studies, differences in TMA(O) metabolism in animal models and the risk of failing to replicate multi-enzyme/multi-strain pathways when using isolated bacterial strains. The purpose of this research was to investigate TMA production from dietary precursors in an in-vitro model of the human colon. Methods TMA production from choline, l -carnitine, betaine and γ-butyrobetaine was studied over 24–48 h using an in-vitro human colon model with metabolite quantification performed using LC–MS. Results Choline was metabolised via the direct choline TMA-lyase route but not the indirect choline–betaine-TMA route, conversion of l -carnitine to TMA was slower than that of choline and involves the formation of the intermediate γ-BB, whereas the Rieske-type monooxygenase/reductase pathway for l -carnitine metabolism to TMA was negligible. The rate of TMA production from precursors was choline > carnitine > betaine > γ-BB. 3,3-Dimethyl-1-butanol (DMB) had no effect on the conversion of choline to TMA. Conclusion The metabolic routes for microbial TMA production in the colon model are consistent with observations from human studies. Thus, this model is suitable for studying gut microbiota metabolism of TMA and for screening potential therapeutic targets that aim to attenuate TMA production by the gut microbiota. Trial registration number NCT02653001 ( http://www.clinicaltrials.gov ), registered 12 Jan 2016.
Impact of wheat aleurone on biomarkers of cardiovascular disease, gut microbiota and metabolites in adults with high body mass index: a double-blind, placebo-controlled, randomized clinical trial
PurposeAleurone is a cereal bran fraction containing a variety of beneficial nutrients including polyphenols, fibers, minerals and vitamins. Animal and human studies support the beneficial role of aleurone consumption in reducing cardiovascular disease (CVD) risk. Gut microbiota fiber fermentation, polyphenol metabolism and betaine/choline metabolism may in part contribute to the physiological effects of aleurone. As primary objective, this study evaluated whether wheat aleurone supplemented foods could modify plasma homocysteine. Secondary objectives included changes in CVD biomarkers, fecal microbiota composition and plasma/urine metabolite profiles.MethodsA parallel double-blind, placebo-controlled and randomized trial was carried out in two groups of obese/overweight subjects, matched for age, BMI and gender, consuming foods supplemented with either aleurone (27 g/day) (AL, n = 34) or cellulose (placebo treatment, PL, n = 33) for 4 weeks.ResultsNo significant changes in plasma homocysteine or other clinical markers were observed with either treatment. Dietary fiber intake increased after AL and PL, animal protein intake increased after PL treatment. We observed a significant increase in fecal Bifidobacterium spp with AL and Lactobacillus spp with both AL and PL, but overall fecal microbiota community structure changed little according to 16S rRNA metataxonomics. Metabolomics implicated microbial metabolism of aleurone polyphenols and revealed distinctive biomarkers of AL treatment, including alkylresorcinol, cinnamic, benzoic and ferulic acids, folic acid, fatty acids, benzoxazinoid and roasted aroma related metabolites. Correlation analysis highlighted bacterial genera potentially linked to urinary compounds derived from aleurone metabolism and clinical parameters.ConclusionsAleurone has potential to modulate the gut microbial metabolic output and increase fecal bifidobacterial abundance. However, in this study, aleurone did not impact on plasma homocysteine or other CVD biomarkers.Trial RegistrationThe study was registered at ClinicalTrials.gov (NCT02067026) on the 17th February 2014.
Strongyloides stercoralis contamination and risk factors in market vegetables: hidden dangers of communities living under poverty plate
Background Strongyloidiasis, caused by Strongyloides stercoralis ( S. stercoralis) spreads through environmental contamination and poor food safety, posing high risks in especially in tropical regions. However, limited research exists on the contamination and transmission pathways in local markets. This study evaluated S. stercoralis exposure, the likelihood of occurrence of risk, and associated risk factors in vegetables to enhance food safety. Methods A cross-sectional study that involved both field and laboratory investigations was conducted in Debre Tabor City, Ethiopia, analyzing S. stercoralis contamination in 360 randomly selected vegetable samples collected from five randomly selected markets. Standard parasitological techniques were used to detect larvae, and structured questionnaires were administered to vendors. One-way ANOVA, risk score and logistic regression were employed using SPSS version 28.0. Results The overall prevalence of S. stercoralis contamination in vegetables was 32.5%, with the highest contamination rates observed in leafy vegetables such as lettuce (26.9%) and cabbage (26.4%). The overall estimated risk score of Strongyloidiasis occurrence is 0.61, with the highest risk from leafy vegetables (lettuce: 1.00, cabbage: 0.89, spinach: 0.87) and the lowest from green pepper (0.14). Lettuce had 2.3 times higher odds of contamination compared to non-leafy vegetables. Vendors with no formal education had 3.6 times higher odds (AOR: 3.6, 95% CI: 2.02–6.54) of selling contaminated vegetables than those with secondary education or higher. Untrimmed fingernails were associated with a 4.8-fold increased risk (AOR: 4.8, 95% CI: 2.81–8.12) of contamination. Afternoon-collected vegetables had 2.02 times higher odds (AOR: 2.02, 95% CI: 1.17–3.51) of contamination than morning-collected samples. Transporting vegetables by carts significantly increased contamination risk (AOR: 3.7, 95% CI: 1.74–7.71) compared to car transportation. Conclusions and recommendations The findings identified leafy vegetables as a significant risk factor for exposure to S. stercoralis . Targeted interventions, improved hygiene, proper handling, and food safety policies are essential to mitigate S. stercoralis contamination risks.
Olfactory impairment in older adults is associated with poorer diet quality over 5 years
Purpose Decreased smell could cause appetite suppression and malnutrition. However, there is a paucity of longitudinal data between olfaction and nutritional status in older adults. We aimed to prospectively examine the relationship between olfactory impairment and overall diet quality (reflecting adherence to dietary guidelines) in a population-based cohort of older adults. Methods We used 5-year follow-up data from 557 adults (aged 60+ years at baseline) whose olfaction was measured using the San Diego Odor Identification Test (SDOIT). Dietary data were collected using a validated semiquantitative food frequency questionnaire. A total diet score (TDS) was calculated for intake of selected food groups and nutrients for each participant as described in the national dietary guidelines. Final scores ranged from 0 to 20; higher scores indicated closer adherence to dietary guidelines. Results After adjusting for all potential confounders, older adults with moderate/severe olfactory impairment (SDOIT score ≤ 3; lower scores indicate impairment) compared with those with no olfactory impairment had significantly lower adjusted mean (±SE) TDS, 9.09 (0.40) versus 9.94 (0.10), p   =  0.04. Women with moderate/severe impaired olfaction (i.e., scored poorly on the odor identification test) compared with those with normal olfaction had significantly lower adjusted mean TDS, 8.87 (0.69) versus 10.31 (0.13), p   =  0.04. No associations were observed between olfaction and TDS in men. Conclusions Olfactory impairment in older women could signal an increased risk of poorer diet quality, defined as adherence to national dietary guidelines. Additional longitudinal studies are needed to confirm or refute the observed link between olfactory loss and overall patterns of food intake in older adults.
Cueing vocabulary in awake subjects during the day has no effect on memory
Background It is assumed that the beneficial effect of sleep on memory relies on spontaneous reactivation of memories during sleep. We recently showed that reactivation by re-exposure to previously learned foreign vocabulary cues during sleep benefits vocabulary learning. Cueing foreign vocabulary during active or passive wakefulness at night did not improve memory, suggesting that memory benefits of cueing are specific to sleep. However, the ineffectiveness of cueing during wakefulness might also be explained by increased tiredness of the participants in this former study. Objectives To exclude tiredness as a confounding factor, we tested the effect of vocabulary cueing during active and passive daytime wakefulness. It was hypothesized that cueing during waking does not improve memory consolidation, even when participants are well rested. Methods A total of 32 subjects learned 120 Dutch–German word pairs. During a 3 h retention interval, parts of the previously learned Dutch words were replayed. Subjects of the active waking group ( N  = 16) were distracted from hearing the Dutch words by an n-back task, while subjects of the passive waking group ( N  = 16) were not distracted. After the retention interval, memory for word pairs was tested by a cued recall. Results Replay of Dutch words during daytime wake did not improve later memory for the German translation in either of the waking groups. We observed no difference in recall performance between cued and uncued words, neither in the active waking nor in the passive waking group. Conclusion Cueing Dutch words during wakefulness does not exert beneficial effects on memory, even when subjects are well rested and under full control of their cognitive capacities. This result gives further evidence that the beneficial effects of cueing are solely specific to sleep.
Olfactory Discrimination of Species, Sex, and Sexual Maturity by the Hermann's Tortoise Testudo Hermanni
Many animals obtain reliable information about potential mates, including whether they are conspecific, sexually mature, and healthy or not, mostly from olfactory cues. Previous experiments with snakes and lizards have shown that individuals can recognize conspecifics, sex, mating status, and health condition of potential partners by chemical cues. Using choice experiments, we examined whether both male and female Hermann's Tortoises, Testudo hermanni, can detect and distinguish the odor of conspecifics from that of another species and an odorless control, and are able to discriminate sex and sexual maturity of individuals by chemical cues. We found that both sexes correctly discriminated between their own species and another species' odors, but only males can distinguish sex and sexual maturity of potential mates by olfactory cues. These results indicate a sexual dimorphism in olfactory sensitivity in this species that might be derived from sexual selection and suggest that males and females should rely on different communication channels during social interactions.