Peptides in wine

Moreno-Arribas, M.V., Pueyo, E., and Polo, M.C. (2002). Analytical methods for the characterization of proteins and peptides in wines. Anal. Chim. Acta, 458, 63-75. 

Analytical determination of peptides in wine requires sample preparation, involving their isolation from the remaining components, mainly high molecular weight nitrogen compounds, free amino acids and phenols. Table 6B.1 summarizes the procedures used in the literature for the extraction of wine peptides before their analysis by different analytical techniques and with different detection systems. 

Yanai, T, Suzuki, I., Sato, M. (2003). Prolyl endopeptidase inhibitory peptides in wine. Biosc. Biotech. Biochem., 67, 380-382. 

Online photodiode array detection and OPA-derivatization have been used to corroborate the peptidic nature of the peaks obtained by RP-HPLC and to identify the aromatic amino acid residues contained in wine peptides (104a). Figure 3 shows the flowchart proposed by the authors for the interpretation of both spectral data and OPA-fluorescence response. 

Together with proteins and peptides, amino acids constitute the main components of the nitrogenous fraction of musts and wines. They are also the most studied and best known nitrogenated components in wines. Free amino acids in musts are of paramount importance. They constitute a source of nitrogen for yeasts in alcoholic fermentation, for lactic acid bacteria in malolactic fermentation, and can also be a source of aromatic compounds (Kosir and Kidric, 2001). In certain cases, some amino acids... 

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 following an analytical separation step like CE, to study and measure a wide variety of compounds in complex samples such us foods (Simo 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 spectrometry (CE-TOE-MS) to analyze directly biogenic amines in wine samples without any previous treatment has been studied (Simo et al. 2008). 

In wines, peptides are the least known nitrogen compounds, in spite of the fact that they are involved in diverse properties such as tensioactivity (Gonzalez-Llano et al. 2004), sensorial activity (Desportes et al. 2001) and antihypertensive activity (Pozo-Bay6n et al. 2005), among others. Also they can act as nutrients for yeasts... 

In the first study appearing in the literature on wine peptides, Acedo et al. (1994) applied RP-HPLC to separate peptides from wine after the formation of peptide derivatives with o-phthaldialdehyde. Also an RP-HPLC procedure using a Nova-Pak Cig column under gradient conditions was applied to analyze peptides... 

Peptides are commonly detected by absorbance at 200-220 nm. However, most of the compounds present in wine may interfere in the ultraviolet detection of peptides when low wavelengths are used. Thus, for the analysis of these compounds it is useful to apply sensitive and selective detection methods. To this end, it is possible to form derivates of the peptides that can be detected at higher and more specific wavelengths. Detection by fluorescence can also be used to detect peptides containing fluorescence amino acids (tyrosine and tryptophan). For peptides without this property, the formation of derivates with derivatizing agents have been proved to be very useful (Moreno-Arribas et al. 1998a). 

Table 6B.3 Sequences of peptides described in wines (range of concentration reported)...

Glutathione is a peptide of non-proteic origin, present in grapes and wines that merits a special mention. It was described for the first time in grapes by Cheynier et al. (1989). Because of its strong antioxidant properties, it has been recommended as an additive to prevent the enzymatic browning of white wines (Vaimakis and Roussis 1996). Nevertheless, neither its evolution during wine manufacture nor its precise role in wine manufacture are fully understood. 

In spite of the lack of studies regarding the antihypertensive effect of wine peptides, in one of them, Takayanagi and Yokotsuka (1999) have determined the ACE inhibitory activity of two red and four white wines in grapes of the black Muscat Bailey A variety and in the fermented musts. They demonstrated that red wines had a higher ACE inhibitory activity than white wines. They also observed that this activity decreases during fermentation without any clear explanations for this reduction. 

Recently ACE inhibitory activity has also been found in peptides released from Saccharomyces cerevisiae in a model wine (Alcaide-Hidalgo et al. 2007). In this assay there were no phenolic compounds, so this activity was exclusively attributed to yeast peptides. The same peptide-rich fractions also showed antioxidant activity, suggesting that peptides released by S. cerevisiae during autolysis in wine conditions could present multifunctional activity. 

Also, prolylendopeptidase inhibitory peptides (PEP) have been found in wines (Yanai et al. 2003). PEP may have a role in the degradation of biologically active peptides containing proline, such as oxytocin, vasopressin, substance P, bradykinin, neurotensins and angiotensins. Two inhibitory peptides have been isolated and characterized, Pep A (Val-Glu-Ile-Pro-Glu) and Pep B (Tyr, Pro, He, Pro, Phe). Both of them showed PEP inhibition, thereby suppressing the degradation of neuropeptides, vasopressin, substance P and fragments 8-13 of neurotensin, which are involved in memory and neural communication. 

Moreno-Arribas, V, Pueyo, E., Polo, M.C. (1996). Peptides in musts and wines. Changes during the manufacture of cavas (sparkling wines). J. Agric. Food Chem., 44, 3783-3788. 

Person, M. de, Sevestre, A., Chaimbault, P., Perrot, L., Duchiron, E, Elfakir, C. (2004). Characterization of low-molecular weight peptides in champagne wine by liquid chromatogra-phy/tandem mass spectrometry. Anal. Chim. Acta, 520, 149-158. 

Yokotsuka, K., Aihara, T., Umehara, Y, Kushida, T. (1975). Free amino acids and peptides in must and wines from jspsnese grapes. 7. Fermen. TechnoL, 53, 631-635. 

Chalier et al. (2007), using mannoprotein at levels usually found in wines (150 mg/L), compared the effect of a whole mannoprotein extract (isolated from a synthetic medium subjected to alcoholic fermentation) to that of well characterized different mannoproteins fractions. From the four wine aroma compounds studied (isoamyl acetate, hexanol, ethyl hexanoate and /3-ionone), all except isoamyl acetate showed a decrease in volatility (up to 80%) when mannoproteins were present (Fig. 8F.3). They suggested that both the glycosidic and the peptidic parts of these macromolecules may be responsible for the interaction. They also found that the interactions of the whole mannoprotein extract Vs. mannoprotein fractions were different, suggesting that the conformational and compositional structure of these... 

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