Two-Month administration of Methylphenidate improves olfactory sensitivity and suppresses appetite in individuals with obesity

Introduction: Olfaction contributes to feeding behaviour and is modulated by changes in dopamine levels. Methylphenidate (MPH) increases brain dopamine levels and has been shown to reduce appetite and promote weight loss in patients with attention deficit hyperactivity disorder. The objectives of this study were to test the effect of MPH on olfaction, appetite, energy intake and body weight on individuals with obesity. Methods: In a randomized, double-blind study, 12 participants (age 28.9±6.7 yrs) (BMI 36.1±4.5 kg/m2) were assigned to MPH (0.5mg/kg) (n=5) or Placebo (n=7) twice daily for 2 months. Appetite (Visual Analog Scale), odour threshold (Sniffin’ Sticks®), energy intake (food menu), and body weight (DEXA scan) were measured at day 1 and day 60. Results: MPH intake significantly increased odour threshold scores (6.3±1.4 vs. 9.4±2.1 and 7.9±2.3 vs. 7.8±1.9, respectively; p=0.029) vs. Placebo. There was a significantly greater suppression of appetite sensations (desire to eat (p=0.001), hunger (p=0.008), and prospective food consumption (p=0.003)) and an increase in fullness (p=0.028) over time in the MPH vs. Placebo. Conclusions: MPH suppressed appetite and improved olfactory sensitivity in individuals with obesity. These data provide novel findings on the favourable effects of MPH on appetite and weight regulation in individuals living with obesity.

Impact of processing on important cocoa off-flavour compounds

The compounds responsible for smoky and mouldy–musty off-flavours in fermented cocoa have recently been elucidated; however, their behaviour during further processing into chocolate was still unclear. The compounds 2-methoxyphenol, 3-methylphenol, 4-methylphenol, 3-ethylphenol, 4-ethylphenol, and 3-propylphenol known to contribute to smoky off-flavours showed a tendency towards a minor increase during roasting and processing into cocoa liquor. This increase amounted to 1.4-fold at the most, however, was clearly compensated by losses of 30–63% during further processing into chocolate mass and conching. Among the off-flavour compounds identified in mouldy–musty smelling cocoa, faecal, mothball-like 3-methyl-1H-indole showed a clear decrease during roasting and processing into cocoa liquor, at least at rather high roasting temperatures, and a further decrease during processing into chocolate mass and conching. In contrast, faecal, mothball-like 1H-indole substantially increased during roasting and processing into cocoa liquor, namely from concentrations below its odour threshold value to concentrations up to 8 times beyond its odour threshold value. During processing into chocolate mass and conching, 1H-indole remained virtually unchanged. The data suggested that the monitoring of off-flavour compounds at the incoming goods inspection in the chocolate industry should not be limited to the fermented beans as such but additionally include the analysis of a bean sample after test roasting to correctly assess the off-flavour potential of 3-methyl-1H-indole and 1H-indole.

Acupuncture is associated with a positive effect on odour discrimination in patients with postinfectious smell loss—a controlled prospective study

Introduction Smell disorders are common in the general population and occur e.g., after infections, trauma or idiopathically Treatment strategies for smell loss range from surgery, medication to olfactory training, depending on the pathology, but they are limited This study examined the effect of acupuncture on olfactory function. Methods Sixty patients with smell loss following infections of the upper respiratory tract were included in this investigation Half of the study group were randomly assigned to verum acupuncture and the other half to sham acupuncture Olfaction was measured by means of the “Sniffin’ Sticks” test battery (odour threshold, discrimination and identification). Results Compared to sham acupuncture, verum was associated with an improvement of smell function as measured by the TDI score (p = 0.039) The improvement was largely determined by improvement in odour discrimination, and was significantly better in patients with a shorter duration of the disorder. Conclusion The present results suggest that acupuncture is an effective supplementary treatment option for patients with olfactory loss.

Odour-active compounds in liquid malt extracts for the baking industry

An odorant screening by gas chromatography–olfactometry (GC–O) and a crude aroma extract dilution analysis (AEDA) applied to the volatiles isolated from a light and a dark liquid malt extract (LME) by solvent extraction and solvent-assisted flavour evaporation (SAFE) identified 28 odorants. Fifteen major odorants were subsequently quantitated and odour activity values (OAVs) were calculated as ratio of the concentration to the respective odour threshold value (OTV). Important odorants in the light LME included 3-(methylsulfanyl)propanal (OAV 1500), (E)-β-damascenone (OAV 430), and 4-ethenyl-2-methoxyphenol (OAV 91). In the dark LME, sotolon (OAV 780), 3-(methylsulfanyl)propanal (OAV 550), (E)-β-damascenone (OAV 410), acetic acid (OAV 160), and maltol (OAV 120) were of particular importance. To get an insight into the changes during malt extract production, the quantitations were extended to the malt used as the starting material for both LMEs. Addition of a minor amount of water to malt before volatile extraction was shown to be effective to cover the free as well as the bound malt odorants. Results showed that some LME odorants originated from the starting material whereas others were formed during processing. Important process-induced LME odorants included (E)-β-damascenone and 4-ethenyl-2-methoxyphenol in the light LME as well as maltol, sotolon, (E)-β-damascenone, and 2-methoxyphenol in the dark LME. In summary, the odorant formation during LME production was shown to be more important than the transfer of odorants from the malt.

The effects of caffeine on olfactory function and mood: an exploratory study

Caffeine has been demonstrated to enhance olfactory function in rodents, but to date, the sparse research in humans has not shown any equivalent effects. However, due to the methodological nature of those human studies, a number of questions remain unanswered, which the present study aimed to investigate. Using a double-blind experimental design, participants (n = 40) completed baseline mood measures, standardised threshold and identification tests and were then randomly allocated to receive a capsule containing either 100 mg of caffeine or placebo, followed by the same olfactory tests and mood measures. Results revealed that despite a trend toward elevated arousal following caffeine for habitual caffeine consumers, there were no changes in odour function. In contrast, for non-caffeine consumers, caffeine acted to enhance odour (threshold) sensitivity but reduce odour identification. Overall, these findings demonstrate a complex profile of effects of caffeine on odour function and, given the evidence from the wider caffeine literature, it is proposed that the effects of caffeine might be limited to older populations.

Human odour thresholds are tuned to atmospheric chemical lifetimes

In this study, the odour thresholds (OT) and atmospheric lifetimes (AL) were compared for a suite of volatile organic compounds. It was found that odour threshold, as determined by the triangle bag method, correlated surprisingly well with atmospheric lifetime for a given chemical family. Molecules with short atmospheric lifetimes with respect to the primary atmospheric oxidant OH tend to be more sensitively detected by the human nose. Overall the correlation of odour threshold with atmospheric lifetime was better than with mass and vapour pressure. Several outliers from the correlations for particular chemical families were examined in detail. For example, diacetyl was an outlier in the ketone dataset that fitted the trend when its more important photolysis lifetime was included; and similarly, the relatively low odour threshold of carbonyl sulfide (OCS) was interpreted in terms of uptake by vegetation. The OT/AL relationship suggests that OH rate constants can be used as a first-order estimate for odour thresholds (and vice versa ). We speculate that the nose's high sensitivity to chemicals that are reactive in the air is likely an evolved rather than a learned condition. This is based on the lack of dependence on ozone in the aliphatics, that the anthropogenically emitted aromatic compounds had the worst correlation, and that OCS had a much lower than predicted OT. Finally, we use the OT/AL relationships derived to predict odour thresholds and rate constants that have not yet been determined in order to provide a test to this hypothesis. This article is part of the Theo Murphy meeting issue ‘Olfactory communication in humans’.

Factors Influencing the Flavour of Bovine Milk and Cheese from Grass Based versus Non-Grass Based Milk Production Systems

There has been a surge in interest in relation to differentiating dairy products derived from pasture versus confined systems. The impact of different forage types on the sensory properties of milk and cheese is complex due to the wide range of on farm and production factors that are potentially involved. The main effect of pasture diet on the sensory properties of bovine milk and cheese is increased yellow intensity correlated to β-carotene content, which is a possible biomarker for pasture derived dairy products. Pasture grazing also influences fat and fatty acid content which has been implicated with texture perception changes in milk and cheese and increased omega-3 fatty acids. Changes in polyunsaturated fatty acids in milk and cheese due to pasture diets has been suggested may increase susceptibility to lipid oxidation but does not seem to be an issue to due increased antioxidants and the reducing environment of cheese. It appears that pasture derived milk and cheese are easier to discern by trained panellists and consumers than milk derived from conserved or concentrate diets. However, milk pasteurization, inclusion of concentrate in pasture diets, cheese ripening time, have all been linked to reducing pasture dietary effects on sensory perception. Sensory evaluation studies of milk and cheese have, in general, found that untrained assessors who best represent consumers appear less able to discriminate sensory differences than trained assessors and that differences in visual and textural attributes are more likely to be realized than flavour attributes. This suggests that sensory differences due to diet are often subtle. Evidence supports the direct transfer of some volatiles via inhalation or ingestion but more so with indirect transfer post rumen metabolism dietary components. The impact of dietary volatiles on sensory perception of milk and dairy products obviously depends upon their concentration and odour activity, however very little quantitative studies have been carried out to date. Some studies have highlighted potential correlation of pasture with enhanced “barny” or “cowy” sensory attributes and subsequently linked these to accumulation of p-cresol from the metabolism of β-carotene and aromatic amino acids or possibly isoflavones in the rumen. p-Cresol has also been suggested as a potential biomarker for pasture derived dairy products. Other studies have linked terpenes to specific sensory properties in milk and cheese but this only appears to be relevant in milk and cheese derived from unseeded wild pasture where high concentrations accumulate, as their odour threshold is quite high. Toluene also a product of β-carotene metabolism has been identified as a potential biomarker for pasture derived dairy products but it has little impact on sensory perception due to its high odour threshold. Dimethyl sulfone has been linked to pasture diets and could influence sensory perception as its odour threshold is low. Other studies have linked the presence of maize and legumes (clover) in silage with adverse sensory impacts in milk and cheese. Considerably more research is required to define key dietary related impacts on the flavour of milk and cheese.

Identification of biphenyls – contaminants responsible for off-flavour in soft drinks

Off-flavour in soft drinks is one of the main threats to manufacturers, which can result in expensive recalls, and discredit the brand. Off-flavours can occur for a variety of reasons (e.g . chemical contamination of raw material). The presented case study has proved there is a relationship between the identification of biphenyl and its derivatives in the used preser vative (benzoate) and off-flavours in the drink . The project consisted of three phases: (1) the assessment of the probable cause of off-f lavours based on sensor y evaluation and GC-MS -Olfactometr y profiling of volatiles; (2) the quantification of biphenyls and the characterisation of their sensor y properties; (3) the screening of commercially available benzoates for the presence of biphenyls. Based on the odour threshold obtained by GC-O (0.03 mg/l for 4-methyl-1,1'-biphenyl and 0.02 mg/l for biphenyl in an aqueous solution) and the common benzoate content in soft drinks (0.14 g/l), the ‘non-obser vable sensory’ levels of contamination were determined to be maximally 0.143 mg/g of benzoate for biphenyl and 0.214 mg/g of benzoate for 4-methyl-1,1 '-biphenyl .

Comparing inhalation and ingestion exposure to chemical contaminants and odorants in mixtures

Chemical spills polluting drinking water are often mixtures with each chemical having unique characteristics for partitioning, toxicity, and odour leading to significant differences in human risk exposures. A 2014 chemical spill of crude (4-methylcyclohexyl)methanol (MCHM) resulted in a $126 million USD fine to the water utility. The spill consisted of at least ten chemicals including 34% cis- and 60% trans-4-MCHM and 0.7% cis- and 0.3% trans-methyl-4-methylcyclohexanecarboxylate (MMCHC). While a very minor component, trans-MMCHC contributed substantially to odour because of its high Henry's Law Constant, 2.23 × 10−2 at 40 °C showering, and low odour threshold concentration (OTC), 0.02 ppb-v, air. Using USEPA risk assessment parameters in a 15-minute shower model with influent concentration of 42 ppb-aq cis- and trans-4-MMCHC, representative of initial spill concentrations in the distribution system, adult ingestion and inhalation for trans-MMCHC were almost equal, 4.00 × 10−4 and 4.26 × 10−4 mg/kg/d, respectively. For children, inhalation doses exceeded ingestion dose: 1.72 × 10−3 mg/kg/d versus 0.93 × 10−3 mg/kg/day trans-MMCHC. This exposure assessment with varying OTC for crude MCHM chemicals reinforces considering chemical, physical, and biological properties of all chemicals in the spill. Consumers aware of their exposure to chemicals in drinking water lost consumer confidence; the water utility was required to compensate individuals and businesses for financial losses.