Biogenic amines are basic nitrogenous low molecular weight compounds with biological activity that may be formed or catabolised during the normal metabolism of animals, plants and micro-organisms.
Biogenic amines are derived mainly from amino acids through substrate-specific decarboxylase enzymes (Fig. 1). Amines may be formed by yeasts during the alcoholic fermentation (mostly putrazine); by lactic acid bacteria (LAB) during malolactic fermentation (MLF) and during maturation of wines. Biogenic amines can also be present in the must, just as putrescine in grapes is associated with potassium deficiencies in the soil. The main biogenic amines in wine are histamine, tyramine, putrescine, cadaverine and phenylethylamine.
|Oenococcus, Lactobacillus and Pediococcus are able to produce biogenic amines. MLF starter cultures of O. oeni are selected not to form biogenic amines in wine and pediococci are usually associated with wines that have very high levels. Micro-organisms decarboxylise amino acids in order to provide the cell with energy and to protect the cell against acidic environments by increasing the pH.
Biogenic amines are important because they contain a health risk for sensitive individuals. Symptoms include nausea, respiratorial discomfort, hot flushes, cold sweat, palpitations, headaches, red rash, high or low blood pressure. Alcohol and acetaldehyde have been found to increase the sensitivity to biogenic amines.
High levels of biogenic amines correlate fairly well with other wine spoilage components for example butyric acid, lactic acid, acetic acid, ethylacetate and diethyl succinate. Which is why wines with higher levels usually also have higher levels of volatile acid. Red wines also have higher levels than white wines, mainly because of vinification practices and maturation.
An increase in the levels of biogenic amines usually occurs towards the end of the MLF or during maturation, when lactobacilli and pediococci are the biggest culprits. The levels of biogenic amines in wines from different countries differ quite a bit and have also changed over the years due to vinification practices (Table 1).
At this stage there are no legal limits, but certain countries have recommended maximum limits with regard to histamine levels (mg/L) that are applicable to imported wines:
Switzerland – 10
France – 8
The Netherlands – 3
Belgium – 5-6
Germany – 2
Austria – 10
Factors influencing biogenic amine formation:
levels of SO2
presence of precursor amino acids
number of decarboxylase positive LAB
duration of the initial fermentation phase
time of skin contact
turbidity of wine during barrel maturation (lees contact)
Aids to control biogenic amine production in wine
Management of pH in wine is one of the most important parameters, since a pH of above 3.5 promotes the growth of lactobacilli and pediococci and the initial numbers on grapes may also be higher. Spontaneous MLF has the potential to have higher levels than when MLF starter cultures are being used, since they are selected not to have this characteristic and they also suppress competing LAB. If you know that your pH is high, rather use lysozyme to remove the natural LAB as quickly as possible from the fermentation.