6A Amino Acids and Biogenic Amines 167
has been paid to the influence of malolactic fermentation on the whole amino acid
composition of wine (Soufleros et al. 1998), and in particular, the effect of the
lactic acid bacteria strain involved in malolactic fermentation on this important wine
nitrogenous fraction is still little known.
Pozo-Bay ́on et al. (2005) studied the evolution of free amino acids during indus-
trial malolactic fermentation carried outby four different starter cultures of the
speciesOenococcus oeniandLactobacillus plantarum. They showed a signifi-
cantly different evolution of methionine inO. oeniandL. plantarumwines, prob-
ably due to the different capacities to catabolize methionine in these two lactic
acid bacteria. In addition to methionine, significant differences were also found
inO. oeniandL. plantarumwines for tryptophan and threonine.L. plantarum
degraded these amino acids, whileO. oenidid not. Moreover, concentration values
of seven of the 21 amino acids determined in the wines studied by these authors,
especially those of glutamine, glycine, -alanine, -alanine, GABA, valine and
lysine, varied significantly depending on the bacterial strain performing the mal-
olactic fermentation.
On the other hand, other studies focused onO. oeniamino acid requirements for
growth and malolactic fermentation in several growth media (Tracey and Britz 1989).
Remize et al. (2006) determined the essential amino acids for the growth of five
different strains ofOenococcus oeni. These amino acids corresponded to glutamic
acid, methionine, phenylalanine, serine and tyrosine for all the strains studied. They
also found that the amino acids valine, leucine, tryptophan, isoleucine, histidine and
arginine were essential or necessary for the strains studied, but that the amino acids
alanine, glycine and proline were not essential.
In a recent study, Fern ́andez and Manca de Nadra (2006) studied the changes
in free amino acids produced by lactic acid bacteria. They identified the amino
acids mainly consumed by a strain ofPediococcus pentosaceus(glutamic acid,
arginine, phenylalanine, glycine, histidine, isoleucine, methionine, serine, tyrosine,
threonine, tryptophan) and those released at the end of the growth process of
O. oeni(aspartic acid, glutamic acid, alanine, arginine, glycine, isoleucine, leucine,
lysine, serine, threonine and valine). When these two strains were grown together, a
rise was observed in the amino acids glutamic acid, alanine, asparagine, pheny-
lalanine, histidine, isoleucine, leucine, serine, tyrosine and valine, compared to
the pureO. oenistrain. These results indicate that proteolytic stimulation of the
system by the mixture of these two bacteria increases the release of essential amino
acids.
6A.3 Biogenic Amines
Biogenic amines in wine can originate from the grape berries themselves or be pro-
duced during fermentation processes, aging or storage, when wine is exposed to the
undesirable activity of decarboxylase-positive microorganisms. Contamination may
occur from poor sanitary conditions of both grapes and processing equipment. Most