Analysis tannin

Hplc techniques are used to routinely separate and quantify less volatile compounds. The hplc columns used to affect this separation are selected based on the constituents of interest. They are typically reverse phase or anion exchange in nature. The constituents routinely assayed in this type of analysis are those high in molecular weight or low in volatility. Specific compounds of interest include wood sugars, vanillin, and tannin complexes. The most common types of hplc detectors employed in the analysis of distilled spirits are the refractive index detector and the ultraviolet detector. Additionally, the recent introduction of the photodiode array detector is making a significant impact in the analysis of distilled spirits. 

Tannins may be found bound up with magnetite in waterside tube deposits. Degradation products of amines, glycols, polymeric dispersants, chelants, and other organics may also be found and usually are reported in the deposit analysis as a loss on ignition. 

SCHOFIELD p, MBUGUA D M and PELL A N (2001) Analysis of condensed tannins a review, Anim Feed Sci Tech, 91, 21-40. 

CZE is particularly useful for separating anthocyanin dimers or polymeric anthocyanins. Calvo et al. (2004)" separated 13 anthocyanins by CZE including acylated and non-acylated anthocyanins, pyranoanthocyanins, and flavonol derivatives in wine. Saenz-Lopez et al. (2004)" applied CZE to analyze wine aging (1 to 14 yr) as related to monomeric anthocyanins, anthocyanin derivatives, tannins, and fla-vonols. Bicard et al. (1999)" reported the improved detection sensitivity of anthocyanin chemical degradation analysis by CZE. 

Sami-Manchado, P. et al.. Analysis and characterization of wine condensed tannins precipitated by proteins used as fining agent in enology. Am. J. Enol. Viticult., 50, 81, 1999. 

Aronson, J. L., T. J. Schitt, R. C. Walter, M. Taieb, J. J. Tiercelin, D. C. Johnson, C. W. Naeser, and A. E. M. Naim (1976), New geochronologic and palaeomagnetic data from the hominid bearing hadar formation of Ethiopia, Nature Hoi, 323-327. Arpino, P, J. P. Moreau, C. Oruezabal, and E. Flieder (1977), Gas chromatographic-mass spectrometric analysis of tannin hydrolysates from the ink of ancient manuscripts (XI to XVI centuries), /. Chromatogr. 134, 433-439. 

Witch hazel is a shrub, normally attaining a height of 5 to 15 feet, native to the northeastern United States. It has oval leaves and yellow flowers, the latter appearing in October and November, after the leaves have fallen. An early analysis of the air-dried bark of this shrub indicated the presence of 6.75 % of tannins.16 In a subsequent investigation of the bark of witch hazel, Griittner18 found that from these tannins could be isolated a crystal-... 

Broadhurst RB, Jones WT (1978) Analysis of condensed tannins using acidified vanillin. J Sci... 

Ruffed grouse, B. umhellus, feed on staminate flower buds and extended catkins of trembling aspen, P. tremuloides. In winter these birds select specific trees or clones. Analysis for alkaloids, tannins, and other phenolics showed that feeding preferences were not related to the levels of tannin or total phenolics in... 

The APCI source (Table 2.8) has been used for the analysis of various flavonoids, especially flavonols, flavones, flavanones, and chalcones (Table 2.11). APCI is based on gaseous-phase ionization, and is most suitable for compounds that are partially volatile and have a medium polarity. Thus, the application of APCI with respect to analysis of condensed tannins and anthocyanins is more limited. Compared with ESI, APCI produces more fragment ions in the spectrum due to the harsher vaporization and ionization processes. More information about ESI and APCI can be found in Section 1.4.5. 

Behrens, A. et al., MALDI-TOF mass spectrometry and PSD fragmentation as means for the analysis of condensed tannins in plant leaves and needles, Phytochemistry, 62, 1159, 2003. 

Ferret, C., Pezet, R., and Tabacchi, R., Fractionation of grape tannins and analysis by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry, Phytochem. Anal, 14, 202,... 

Fulcrand, H. et al., Electrospray contribution to structural analysis of condensed tannin oligomers and polymers, Basic Life Set, 66, 223, 1999. 

Robbins, M.P. et al.. Genetic manipulation of condensed tannins in higher plants. II. Analysis of birdsfoot trefoil plants harboring antisense dihydroflavonol reductase constructs. Plant Physiol, 116, 1133, 1998. 

Thiolysis also proved useful for the analysis of derived tannins. Methylmethine-linked tannin-like compounds resulting from acetaldehyde-mediated condensation of flavanols (see Section 5.5.S.2) yielded several adducts when submitted to acid-catalyzed cleavage in the presence of ethanethiol, providing information on the position of linkages in the original ethyl-linked compounds. " Thiolysis of red wine extracts released benzylthioether derivatives of several anthocyanin-flavanol adducts, indicating that such structures were initially linked to proanthocyanidins. However, some of the flavonoid derivatives present in wine (e.g., flavanol-anthocyanins ) are resistant to thiolysis, while others (e.g., flavanol-ethyl anthocyanins) were only partly cleaved. Thiolysis, thus, appears as a rather simple, sensitive, and powerful tool for quantification and characterization of proanthocyanidins, but provides mostly qualitative data for their reaction products. 

Fulcrand, H. et al.. Electrospray contribution to structural analysis of condensed tannin oligomers and polymers. In Plant Polyphenols 2. Chemistry, Biology, Pharmacology, Ecology (eds G.G. Gross, R.W. Hemingway, T. Yoshida, and S.J. Branham), Kluwer Academic/Plenum Publisher, New York, 1999, p. 223. 

Downey, M., Harvey, J., and Robinson, S., Analysis of tannins in seeds and skins of Shiraz grapes throughout berry development. Aust. J. Grape Wine Res. 9, 15, 2003. 

Despite their very short sequence (7 to 38 amino acid residues for the 12 histatins identified so far), the histidine-rich salivary protein histatins have also been reported to precipitate tannins, eventually more efficiently than proline-rich proteins, especially at neutral pH and high tannin concentration. A detailed NMR analysis of the binding between EGCG and histatin 5, a 24-mer that is very rich in basic His, Lys, and Arg residues ( 60%) and devoid of secondary structure, has revealed noncooperative binding of six to seven flavanol molecules with a dissociation constant of 1 mM (pH 3.0, 25°C). ... 

Hagerman, A.E., Tannin-protein interactions, in Phenolic Compounds in Food and their Effects on Health I. Analysis, Occurrence, and Chemistry. ACS Symposium Series 506, Ho, C.T., Lee, C.Y., and Huang, M.T., Eds., American Chemical Society, Washington, DC, 1992, 236. 

Laouenan, P. et al., NMR structural investigations and conformational analysis of condensed tannins. A continuing challenge due to restricted rotation about the interflavanyl linkage, Analusis, 25, M29, 1997. 

Various excellent reviews are available on phenolic compounds, their chemistry and analysis, content in foods and nutritional significance (Bravo, 1998 Dykes and Rooney, 2006 Manach et al., 2004 Naczk and Shahidi, 2006 Robbins, 2003). From a nutritional perspective, phenolic compoimds (especially tannins) are regarded as antinutritional factors due to their ability to form complexes with dietary proteins and minerals and digestive enzymes (Bravo, 1998). However, lately there has been increasing focus on the positive aspects of phenolics due to their ability to act as antioxidants which may offer potential health benefits such as prevention of diseases such as cancer and cardiovascular disease. 

From the analysis of Berzelius, It appeared that tannin was composed centesimally as follows — ... 

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