2-bromophenol
“Bromophenol , inky, like a museum or old TV set”
Technical specification
Assessment
Without covering the glass, swirl the sample to release the aroma. Take a single short sniff. Repeat as necessary. Amount of flavour per capsule
9.1 µg Threshold
70 – 230 ng/ l in soft drinks Origins
Bromophenols can taint product through ingredients, water or packaging. Associated with use of recycled wood and cardboard. Can also arise due to growth of Alicyclobacillus. Importance
Imparts an unpleasant note, described by consumers as ‘chemical’ or ‘contaminated’. Often associated with the presence of guaiacol when produced as a result of spoilage by bacteria. CAS registry number
95-56-7 Other names
bromophenol
o-bromophenol
ortho-bromophenol
Remarks
Bromophenolic taints can be caused by several compounds, of which 2-bromophenol is only one. The flavour produced by this compound is typical of the group. Threshold distribution
2,6-dichlorophenol
“Chlorophenol , like antiseptic mouthwash”
2,6-dichlorophenol
500 ng
Technical specification
Assessment
Without covering the glass, swirl the sample to release the aroma. Take a single short sniff. Repeat as necessary. Amount of flavour per capsule
500 ng Threshold
50 - 160 ng / l in soft drinks Origins
Chlorophenols can taint product through ingredients, water or packaging materials. Especially associated with use of recycled wood and cardboard. Importance
Imparts an antiseptic, medicinal note to contaminated products. Regarded by consumers as unpleasant and tainted even at low levels. Produced through reactions involving phenolic compounds and free chlorine. CAS registry number
87-65-0 Other names
1-hydroxy-2,6-dichlorobenzene
2,6-DCP
2,6-dichlorfenol
Remarks
Water pH is important in determining the rate of formation of chlorophenols. Can be produced by bacterial action, often linked to misuse of carbon filters. Accidental use of chlorinated water in product formulation can give rise to this flavour. Threshold distribution
dimethyl sulphide
“DMS , like sweetcorn or tomato sauce”
Technical specification
Assessment
Without covering the glass, swirl the sample to release the aroma. Take a single short sniff. Repeat as necessary. Amount of flavour per capsule
75 µg Threshold
25 µg / l in soft drinks Origins
Contaminant introduced through use of insufficiently-purified carbon dioxide. Can also arise through bacterial spoilage. Importance
Associated with sulphury and ‘muddy’ odours notes. Indicator of contamination of the carbon dioxide supply. DMS can also be indicative of contamination of the water supply chain with faecal bacteria. CAS registry number
75-18-3 Other names
DMS
dimethyl monosulfide
methylsulfanylmethane
methyl monosulfide
methane thiomethane
methyl sulfide
methyl thioether
methylsulfanylmethane
2-thiapropane
thiobis(methane)
thiobismethane
Remarks
Other sulphur compounds may be found alongside dimethyl sulphide in contaminated carbon dioxide. Indole and skatole are often found in water in which DMS has been produced by bacteria. 2-Pentanone may be present in water in which the DMS has been formed by algae. Threshold distribution
ferrous sulphate
“Metallic , like ink or blood”
Technical specification
Assessment
Take a little sample into your mouth. Move it around with your tongue for a few seconds then swallow it. To confirm, rub a little onto the back of your hand and check for metallic odour. Amount of flavour per capsule
5.4 mg Threshold
1.8 mg / l in soft drinks Origins
Derived from contamination of raw materials or process water with metal ions or from or from corrosion of process plant. Metallic odours can also be produced by lipid oxidation Importance
Taint and occasionally off-flavour. Primarily affects product mouthfeel but sometimes product odour, colour and clarity can be affected. CAS registry number
7782-63-0 Other names
ferrous sulfate
iron(2+) sulfate
iron(2+) sulphate
ferrous sulphate heptahydrate
ferrous sulfate heptahydrate
iron(2+) sulfate heptahydrate
iron(II) sulfate heptahydrate
iron(II) sulphate heptahydrate
Remarks
Copper, manganese and other metals can also confer metallic notes in soft drinks. The intensity of metallic notes can be influenced by the type and concentration of product component, including sweeteners, polyphenols and clouding agents. Threshold distribution
2-isobutyl-3-methoxypyrazine
“Earthy , like green pepper”
2-isobutyl-3-methoxypyrazine
60 ng
Technical specification
Assessment
Without covering the glass, swirl the sample to release the aroma. Take a single short sniff. Repeat as necessary. Amount of flavour per capsule
60 ng Threshold
20 ng / l in soft drinks Origins
Introduced through use of contaminated formulation water or process water. Formed by Actinobacteria in lakes, reservoirs and water distribution systems. Importance
Potent off-flavour with a very low flavour threshold. Imparts an unpleasant earthy note which is reminiscent of green peppers. May occur in admixture with other methoxypyrazines. CAS registry number
24683-00-9 Other names
2-methoxy-3-(2-methylpropyl)pyrazine
isobutyl methoxypyrazine
3-isobutyl-2-methoxypyrazine
galbanum pyrazine
2- methoxy-3-(2-methyl propyl) pyrazine
2-methoxy-3-(2-methylpropyl)pyrazine
2-methoxy-3-isobutyl pyrazine
2-2-methyl propyl-3-methoxypyrazine
Remarks
Methoxypyrazine taints can be caused by several compounds, of which 2-isobutyl-3-methoxypyrazine is only one. Water treatment practices should remove the methoxypyrazine prior to use. Threshold distribution
2-isopropyl-3-methoxypyrazine
“Earthy , like potato skins or dug soil”
2-isopropyl-3-methoxypyrazine
6.0 ng
Technical specification
Assessment
Without covering the glass, swirl the sample to release the aroma. Take a single short sniff. Repeat as necessary. Amount of flavour per capsule
6.0 ng Threshold
2 ng / l in soft drinks Origins
Introduced through use of contaminated formulation water or process water. Formed by Actinobacteria in lakes, reservoirs and water distribution systems. Importance
Potent off-flavour with a very low flavour threshold. Imparts an unpleasant earthy / mouldy note which is reminiscent of potato skins or dug soil. May occur in admixture with other methoxypyrazines. CAS registry number
25773-40-4 Other names
bean pyrazine
2-methoxy-3-(1-methyl ethyl) pyrazine
2-methoxy-3-isopropyl pyrazine
2-methoxy-3-propan-2-ylpyrazine
2-isopropyl-3-methoxypyrazine
3-isopropyl-2-methoxypyrazine
Remarks
Methoxypyrazine taints can be caused by several compounds, of which 2-isobutyl-3-methoxypyrazine is only one. Water treatment practices should remove the methoxypyrazine prior to use. Threshold distribution
2,4,6-tribromoanisole
“Musty , like corked wine with a rubbery overtone”
2,4,6-tribromoanisole
450 ng
Technical specification
Assessment
Without covering the glass, swirl the sample to release the aroma. Take a single short sniff. Repeat as necessary. Amount of flavour per capsule
450 ng Threshold
<10 – 500 ng / l in soft drinks Origins
Contaminates product through ingredients, water, air or packaging materials. Associated with use of recycled materials such as wood and cardboard. Derived from methylation of bromophenols by moulds. Importance
Imparts an unpleasant musty odour which is reminiscent of damp cellars or corked wine. This is one of the few flavours that can taint soft drinks through airborne contamination, even after the product has been packaged. CAS registry number
607-99-8 Other names
tribromoanisole
TBA
1,3,5-tribromo-2-methoxybenzene
methyl 2,4,6-tribromophenyl ether
Remarks
2,4,6-Tribromoanisole is one of several bromoanisoles that can taint soft drinks. The flavour produced by this compound is typical. It can be detected, but not recognized at concentrations well below the recognition flavour threshold. Threshold distribution
2,4,6-trichloroanisole
“Musty , like corked wine or a damp cellar”
2,4,6-trichloroanisole
220 ng
Technical specification
Assessment
Without covering the glass, swirl the sample to release the aroma. Take a single short sniff. Repeat as necessary. Amount of flavour per capsule
220 ng Threshold
5 - 100 ng / l in soft drinks Origins
Contaminates product through ingredients, water, air or packaging materials Associated with use of recycled materials such as wood and cardboard. Derived from methylation of chlorophenols by moulds. Importance
Imparts an unpleasant musty odour which is reminiscent of damp cellars or corked wine. This is one of the few flavours that can taint soft drinks through airborne contamination, even after the product has been packaged. CAS registry number
87-40-1 Other names
methyl 2,4,6-trichlorophenyl ether
1,3,5-trichloro-2-methoxybenzene
TCA
Remarks
2,4,6-Trichloroanisole is one of several chloroanisoles that can taint soft drinks. The flavour produced by this compound is typical. It can be detected, but not recognized at concentrations well below the recognition flavour threshold. Threshold distribution
