Mouth odour

Should help to reduce caries, maintain healthy gingiva, improve aesthetics and reduce mouth odours. 

Alkyl sulfides and thiols. Some alkyl thiols and sulfides, notably those from commonly ingested Allium sativum (garlic) and Allium cepa (onion) (Alliaceae), are variously bioactive as odorants and antimicrobials. Propanethial S-oxide (CH3-CH2-CH=S=0) is a lachrymatory irritant principle of onion. Allicin (S-oxodiallydisulfide CH2=CH—CH2-SO-S-CH2— CH=CH2), diallyldisulfide (CH2=CH-CH2-S-S-CH2-CH=CH2) and diallylsulfide (CH2=CH—CH2—S—CH2-CH=CH2) are major odorants of garlic that are reactive and irritant because of the allyl groups. Dimethyl disulfide (CH3—S—S-CH3), dipropyl disulfide (CH3-CH2-CH2-S-S-CH2-CH2-CH3), methyl allyl disulfide (CH3-S-S-CH2-CH=CH2) and propane-1-thiol (CH3-CH2—CH2—SH) are further Allium odorants. Methane thiol (methyl mercaptan CH3—SH) is a widespread plant volatile and notably derives from anaerobic bacterial degradation of cysteine as in human flatus and bad mouth odour. The aliphatic disulfides allicin and ajoene inhibit proinflammatory expression of iNOS. 

Optional experiment. When all the air has been displaced, collect a test-tube of the gas over water (by appropriate inclination of the end of the delivery tube beneath the mouth of a test-tube filled with water and supported in a beaker of water). Observe the colour and odour of the gas. Ignite the test-tube of gas, and note the luminosity of the flame and the amount of carbon deposited. Pure acetylene is almost odourless the characteristic odour observed is due to traces of hydrides of phosphorus, arsenic and sulphur. 

Place 45 g. (43 ml.) of benzal chloride (Section IV,22), 250 ml. of water and 75 g. of precipitated calcium carbonate (1) in a 500 ml. round-bottomed flask fltted with a reflux condenser, and heat the mixture for 4 hours in an oil bath maintained at 130°. It is advantageous to pass a current of carbon dioxide through the apparatus. Filter off the calcium salts, and distil the filtrate in steam (Fig. II, 40, 1) until no more oil passes over (2). Separate the benzaldehyde from the steam distillate by two extractions with small volumes of ether, distil off most of the ether on a water bath, and transfer the residual benzaldehyde to a wide-mouthed bottle or flask. Add excess of a concentrated solution of sodium bisulphite in portions with stirring or shaking stopper the vessel and shake vigorously until the odour of benzaldehyde can no longer be detected. Filter the paste of the benzaldehyde bisulphite compound at the pump... 

An individual who was blind in regard to the odour stimulus presented at each trial repeatedly viewed each test session and scored the following behavioural measures number of lateral head movements, number of hand-to-mouth movements, and frequency of sucking movements with the lips / mouth. 

The distillate from the steam distillation is twice shaken with not too much ether, and the ethereal extract, if necessary after concentration, is transferred to a wide-mouthed bottle, into which technical sodium bisulphite solution is poured in small portions with stirring (a glass rod is used) so that the aldehyde addition compound formed sets to a thick paste. The bottle is then stoppered and vigorously shaken the stopper is removed from time to time until all the benzaldehyde has entered into combination. (Odour ) The paste is now filtered with suction, and the solid on the funnel, after washing with ether, is at once decomposed by mixing it with an excess of sodium carbonate solution the liberated aldehyde is removed without delay by steam distillation. The distillate is extracted with ether, the extract is dried over a little calcium chloride, the ether is removed by distillation, and the benzaldehyde which remains is likewise distilled. Boiling point 179°. Yield 35-40 g. (70 per cent of the theoretical). 

Chilli or paprika is used for flavour, not heat, in some cuisines. Flavour is a complex sensation determined in the mouth. One of the most potent volatiles known to humans is found in chilli, the pyrazine 2-methoxy-3-isobutyl-pyrazine, the green bell pepper smell. Reports indicate that humans can detect this odour at two parts per trillion. Luning et al. (1994) reported the presence of more than 80 odour compounds in C. annuum. C.frutescenscv. Tabasco contained 125 compounds whose relative abundance changed with the season of harvest. The composition of aroma compounds of Tabasco differed significantly from that of the green... 

Place a scoopula tipful of NH4C1 in a test tube. Add 2 mL NaOH. To detect any odour, gently waft your hand over the mouth of the test tube towards your nose. Warm the tube gently (do not boil) over a flame. Record your observations in Table B. 

The gas may be identified (i) by its suffocating odour of burning sulphur, (ii) by the green colouration, due to the formation of chromium(III) ions, produced when a filter paper, moistened with acidified potassium dichromate solution, is held over the mouth of the test-tube. 

The product is recognized (a) by its pungent odour and the production of white fumes, consisting of fine drops of hydrochloric acid, on blowing across the mouth of the tube, (b) by the formation of white clouds of ammonium chloride when a glass rod moistened with ammonia solution is held near the mouth of the vessel, and (c) by its turning blue litmus paper red. 

Or in other more bizarre ways. A 23-year-old medical student saw his dog (a puppy) suddenly collapse. He started external cardiac massage and a mouth-to-nose ventilation effort. Moments later the dog died, and the student felt nauseated, vomited and lost consciousness. On the victim s arrival at hospital, an alert medical officer detected a bitter almonds odour on his breath and administered the accepted treatment for cyanide poisoning after which he recovered. It turned out that the dog had accidentally swallowed cyanide, and the poison eliminated through the limgs had been inhaled by the master during the mouth-to-nose resuscitation. Journal of the American Medical Association 1983 249 353. 

Dose. Established anaerobic infection is treated with metronidazole by mouth 400 mg 8-hourly by rectum 1 g 8-hourly for 3 days followed by 1 g 12-hourly or by i.v. infusion 500 mg 8-hourly. A topical gel preparation is useful for reducing the odour associated with anaerobic infection of fungating tumours. 

The flavour of a food consists of odour, taste, and haptic and tactile sensations in the mouth ( mouthfeel ) (Fig. 3.52). This means that a flavour modifier may affect odour, taste, and/or mouthfeel of a food. Usually, only taste and/or odour are affected, although maltol and ethyl maltol have been reported to be effective in improving the mouthfeel in low-fat food systems [7]. Because of lack of a clear definition, I shall classify flavour modifiers into the five categories shown in Table 3.46. Based on this... 

At this point, it is important to clarify a few terms that are often used in the context of this chapter. Flavour is usually divided into the subsets taste and smell, which are perceived in the mouth and the nose, respectively [3], The terms aroma and odour are not well defined and often used as synonyms. Qdour is best reserved for the smell of food before it is put into the mouth (nasal perception) and aroma for the retronasal smell of food in the mouth. In this paper, we mainly use the terms aroma and taste , as well as flavour comprising sensory notes imparted by both volatile and nonvolatile compounds (odorants and tastants). In the public domain, however, taste is often used as a synonym for flavour . Proper definitions of these terms are ... 

A number of studies have been carried out to determine the levels at which odour can be detected in drinking water. These studies are normally carried out in a laboratory setting with trained panellists in order to maximise the sensitivity of the study. This is important because the number of panellists must be highly restricted, but there is a wide variation in the sensitivity within the population and it is not necessarily possible to cover the full range. Set against this is the fact that under normal circumstances of use individuals would not be routinely seeking to detect odour in water, much water is drunk cold, which reduces the potential for the volatilisation of odorous substances, while other water is boiled resulting in increased loss of such substances before consumers drink the water. In addition, while every effort is made to exclude extraneous odours in the laboratory, this is not the case when the consumer uses the water. Odour and taste are closely linked and in most circumstances both odour and taste thresholds are determined in laboratory studies. In many cases one is clearly lower than the other but with MTBE the data are mixed. This may reflect the volatility of MTBE and its release in the mouth. 

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