Grape seed tannins

Sarni-Manchado, P., Cheynier, V., and Moutounet, M., Interactions of grape seed tannins with salivary proteins. J. Agric. Food Chem. 47, 42, 1999. 

Riou, V. et ak. Aggregation of grape seed tannins in model — effect of wine polysaccharides. Food Hydrocoil 16, 17, 2002. 

Naish, M., Clifford, M.N., and Birch, G.G., Sensory astringency of 5-O-caffeoylquinic acid, tannic acid and grape seed tannin by a time-intensity procedure. J. Sci. Food Agric. 61, 57, 1993. 

Peri and Pompei (35,36) have helped verify the methods elaborated here (9,21), and they have extended them by adapting cinchonine precipitation to separate tannins from nontannins. Thus, in a mixture of the two tannins precipitated by cinchonine they were able to redissolve them and quantitate tannic acid separately from grape seed tannin because of tannic acids failure to precipitate with formaldehyde and by appropriate application of the F-C analysis. They applied these techniques to analysis of... 

Table 2. Hyperchromic effect (measured at 523 nm) of grape seed tannin fraction on MaIvidin-3-Glucoside in tartrate buffer (pH 3.5). mOP is the mean degree of polymerization measured by diioacidolysis. r the molar ratio between tannin and anthocyanin (a fixed concentration of 1 g/1 of tannin was used). T is the absorbance of tannin solution (control) at 523nm.

In order to study the influence of tannin length in the acetaldehyde on the kinetics of bridging reaction, we used the different grape seed tannin fraction (Table 2 and incubated them with malvidin 3-glucoside in presence or absence of a relative excess of acetaldehyde. We followed then the disappearance of anthocyanin by HPLC. The kinetics observed were assimilated to first order kinetics. The corresponding rates were (hen measured and are reported in table 3. 

Fontoin H, Saucier C, Teissedre P-L, Glories Y (2008) Effect of pH, ethanol and acidity on astringency and bitterness of grape seed tannin oligomers in model wine solution. Food Qual Pref 19 286-291... 

Smith AK, June H, Noble AC (1996) Effects of viscosity on the bitterness and astringency of grape seed tannin. Food Qual Pref 7 161-166... 

Tebib, K., Besancon, P., and Rouanet, J.M., Dietary grape seed tannins affect lipoproteins, lipoprotein lipases and tissue lipids in rats fed hypercholesterolemic diets, J. Nutr., 124, 2451, 1994. 

Murga R, Ruiz R, Beltran S and Cabezas JL. 2000. Extraction of natural complex phenols and tannins from grape seeds by using supercritical mixtures of carbon dioxide and alcohol. J Agric Food Chem... 

Fig. 3.6 Tannin crude extract from grape seed separated by normal-phase HPLC with post-coiumn...

Tannins Gallic acid 45 is a phenolic compound found mainly in grape seeds and stems, but also it can be leached from oak barrels, occurring generally in amounts of 10-100mg/L. Two molecules of gallic acid in a head-to-tail fashion are the dilactone ellagic acid 46 ... 

Another method for extraction and purification of tannins from grape seeds and skins was proposed by Vidal et al. (2003). For seeds... 

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