Peptides wines

Chambery, A., del Monaco, G., Di Maro, A., and Parente, A. (2009). Peptide fingerprint of high quality Campania white wines by MALDl-TOP mass spectrometry. Food Chem. 113, 1283-1289. 

A variation on the Thompson and Forward method was developed in which a HA peptide or peptide-like material (e.g., gelatin, gliadin, polyproline, or soluble polyvinylpyrrolidone) is added to a sample to induce haze in proportion to the amount of HA polyphenol it contains (Siebert et al., 1996a). This gives little response in beer, which contains very little HA polyphenol, and causes much larger haze increases in fruit juices and wine. 

Dialysis and ultraflltration have been largely applied to isolate and fractionate food proteins and peptides. To isolate the protein fraction from wine and must samples, different authors used dialysis followed by lyophilization to concentrate the dialyzed samples [106,108,109], Depending on the application, membrane of different material, filtration surface and cut-off, able to fractionate the molecules in function of their molecular size, can be used to remove either proteins and other macromolecules or amino acids and small peptides. 

Leonil et al. [105] and more recently Careri and Mangia [132] reviewed the application of HPLC-MS to the analysis of food proteins and derived peptides. The most studied matrices were milk and derived products, cereals, meat, and wine. 

In heavily sulfited white wines containing over 0.5 ppm copper and stored in sealed containers, a reddish-brown deposit may form. This occurs in the absence of oxygen and ferric ions but redissolves readily upon exposure to oxygen. Its formation may be accelerated by exposure to sunlight or heat, and it is believed to consist of colloidal cupric sulfide (14, 29). More commonly, copper casse may arise from reactions between copper and sulfur-containing amino acids, peptides, and proteins (15,16,17). 

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. 

Recently, the enrichment of proteins by a combinatorial peptide library allowed demonstrating quite easily the presence or the absence of proteins, for instance, in almond s milk and orgeat syrup (65), in coconut milk (66), in a cola drink (67), in ginger ale (68), and even in white wine vinegar that is not really a beverage (69) (see in the succeeding text). 

Wine is one of the most complex and interesting matrices for a number of reasons. It is composed of volatile compounds, some of them responsible for the odor, and nonvolatile compounds which cause taste sensations, such as sweetness (sugars), sourness (organic acids), bitterness (polyphenols), and saltiness (mineral substances Rapp and Mandary, 1986). With a few exceptions, those compounds need to be present in levels of 1%, or even more, to influence taste. Generally, the volatile components can be perceived in much lower concentrations, since our organs are extremely sensitive to certain aroma substances (Rapp et ah, 1986). Carbohydrates (monosaccharides, disaccharides, and polysaccharides), peptides, proteins, vitamins, and mineral substances are among the other wine constituents. 

Due to the lack of scientific studies on the nature and content of polysacharides, peptides, proteins, and vitamins in Madeira wines, they will not be covered in these discussions. 

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... 

The peptide fraction of an industrially manufactured red wine has been studied during MLF, and it was found that wine LAB have the potential to hydrolyze wine proteins (Alcaide-Hidalgo et al. 2008), although some authors have consider that this activity is not widespread among oenococci strains (Leitao et al. 2000). However, the ability of 0. oeni to exhibit extracellular protease activity able to release peptides and free amino acids during MLF in white (Manca de Nadra et al. 1997) and red wines has also been demonstrated (Manca de Nadra et al. 1999). The oligopeptide utilization of 0. oeni was characterized only recently (Ritt et al. 2008) and O. oeni was found to be able to transport oligopeptides with two to five-amino acid residues and then to hydrolyse them further. 

Alcaide-Hidalgo, J., Moreno-Arribas, M.V., Polo, M.C., Pueyo, E. (2008). Partial characterization of peptides from red wines. Changes during malolactic fermentation and aging with lees. Food Chem., 107, 622-630. 

Yeast autolysis could be defined as the hydrolysis of biopolymers under the action of hydrolytic enzymes which releases cytoplasmic (peptides, amino acids, fatty acids and nucleotides) and cell wall (glucans, mannoproteins) compounds into the wine (Alexandre et al. 2006).Usually, autolysis takes place at the end... 

Martinez-Rodriguez, A.J., Carrascosa, A.V., Martln-Alvarez, P.J., Moreno-Arribas, V, and Polo, M.C. (2002). Influence of the yeast strain on the changes of the amino acids, peptides and proteins during sparkling wine production by the traditional method./. Ind. Microbiol. Biot., 29,314-322. 

Moreno-Arribas, V., Bartolome, B., Pueyo, E., and Polo, M.C. (1998a). Isolation and characterization of individual peptides from wine. /. Agric. Food Chem., 46, 3422-3425. 

Care must be taken when fining a sparkling wine with bentonite in order to preserve its foaming properties. Excessive use of bentonite for the fining of sparkling wine cuv es can produce a finished product that has a large bubble size and a poor bubble stability as a result of a reduction in both protein and peptide contents. Cold stabilization procedures cause both a precipitation of potassium bitartrate crystals as well as proteins because of the downward shift in pH. This precipitation of proteins... 

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... 

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