6A Amino Acids and Biogenic Amines 181
reagents. CE also permits a wide variety of compounds to be analysed at low con-
centration levels with a minimum sample treatment. The analysis of different bio-
genic amines in foods by CE with diverse detection methods has been previously
reported in the literature (Onal 2007) and applied to a wide variety of food matrices ̈
including wine (Kov ́aks et al. 1999). A CE method using conductometric detec-
tion and which requires no derivatisation or sample cleaning steps was developed
recently (Kvasnicka and Voldrich 2006). Also, a high-performance capillary elec-
trophoresis (HPCE) method exists to determine biogenic amines in wine, amongst
other foodstuffs (K ́ovacs et al. 1999).
In recent years there has been a growing interest in the use of electrospray
ionization-mass spectrometry (ESI-MS) either as a stand-alone technique, or fol-
lowing an analytical separation step like CE, to study and measure a wide variety
of compounds in complex samples such us foods (Sim ́o et al. 2005). ESI provides
an effective means for ionising from large (e.g., proteins, peptides, carbohydrates)
to small (e.g., amino acids, amines) analytes directly from solution prior to their
MS analysis without a previous derivatization step. Santos et al. (2004) proposed
the use of CE-ESI-MS for the separation and quantification of nine biogenic amines
in white and red wines. More recently, the possibilities of two different CE-MS
set-ups, namely, capillary electrophoresis-electrospray-ion trap mass spectrometry
(CE-IT-MS) and capillary electrophoresis-electrospray-time of flight mass spec-
trometry (CE-TOF-MS) to analyze directly biogenic amines in wine samples with-
out any previous treatment has been studied (Sim ́o et al. 2008).
6A.3.4.3 Enzymatic Methods
Enzymatic methods to quantify histamine were first reported for use in fish. A direct
enzyme-linked immunosorbent assay (ELISA) was applied to determine histamine
in wine samples and the results were compared with those of an HPLC method of
OPA-derivatives for this amine, obtainingconcordant results (Marcobal et al. 2005a).
Because of its simplicity, speed and low cost, the ELISA method can be considered
as an alternative to HPLC and can, at least, be used as a screening tool in laboratories
where chromatographs are not available or that have to analyse a large number of
wines. The development of an enzymatic tool to determine the histamine contents in
wines and its comparison with HPLC has also been published (Landete et al. 2004).
Very good correlation was also established between biogenic amine quantification
using this enzymatic method and HPLC analysis.
6A.3.4.4 Screening Methods Using Selective Media
Most studies to screen for biogenic amine-producing lactic acid bacteria use differ-
ential media that contain the precursor amino acid and a pH indicator. This indicator,
usually purple bromocresol, will change colour when the medium is alkalinized and
this colour change will be observed in the medium if the lactic acid bacteria produce
amines (Bover-Cid and Holzapfel 1999; Choudhury et al. 1990; Maijala 1993).