Tannins determination

Petit-Dominguez, M.D., Garcia-Gimenez, R., and Rucandio, M. I. (2003). Chemical characterization of Iberian amphorae and tannin determination as indicative of amphora contents. Mikrochimica Acta 141 63-68. 

Abstract In this study, a new natural adsorbent (sumae leaves) for removing Cu (II) ion from the aqueous solutions has been investigated. Leaves of sumae were obtained from Siirt, Tmkey. The tannins were extraeted with acetone water (70 30, v/v) mixture from the leaves of sumac. For the total tannin determination Folin-Ciocalteu method was used and tannin content was found 27%. In batch experiments, pH profile, adsorption time, adsorbent/hquid ratio, initial concentration of metal ions, adsorbent amoimt, particle size of adsorbent and temperature were performed to determine binding properties of adsorbent for the Cu(II) ions. The concentrations of the metal ions in solutions before and after adsorption were measured with an atomic absorption spectrophotometer. 

White or yellowish-white, woolly powder, prepared from the best quality of hide from which the hair has been removed with lime and which has been thoroughly washed. Hide powder should have but a slight odor and should lie specially free from odors of decomposition products. It is used for tannin determination. 

As the quantity of water-soluble constituents in the various hido powders varies greatly, it is always necessary, before using a hide powder for tannin determinations, to determine the quantity of soluble constituents by a blank test according to the method described here. 

Finally, the total tannin is calculated as the sum of the combined tannin, determined as above, and the non-combined determined as in section 4. 

One reason that precise and quantitative assays for tannin determinations have been difficult to develop is that tannins encompass a heterogeneous group of compounds and polymers. However, several assays have been developed to estimate tannin levels in extracts, and an excellent review is available (18). Many of these assays are based on either the reduction capabilities of polyphenols or the propensity of tannins to form precipitates with various proteins. The following two assays are best used as a qualitative analysis for the presence or absence of particular tannins, but can be used with standards for approximate tannin determinations. 

For synthesized Gelatin (G)/Tannin (T) resins, gelatin powder was purchased from tilker Food Company-Istanbul, Turkey. Flydrolyzable tannins were obtained from the sumac leaves which were collected from Siirt, Turkey. The raw leaves were dried at room temperature in dark and then ground 500 pm particle sizes. For the total tannin determination Folin-Ciocalteu method was used and tannin content found 27%. Tannins are extracted from sumac leaves with 1 1 (v/v) acetone/water solution [15]. Tannic acid (TA) powder, which was extracted from sumac leaves (30 g) was dissolved in distilled waster at 95-98°C, then solution cooled at room temperature and 37% formaldehyde solution added to the solution. G powder was dissolved distilled water at 95-98°C and then added to the TA/formaldehyde solution. Concentrated hydrochloric acid was added to the mixture and heated 95-98°C for 12 h with a reflux condenser. G/TA resin was washed distilled water, dried at 110°C. Dried resin was crushed into small particles, <500 pm [16]. 

Brugirard and Tavernier (1952) used the property of true tannins of flocculating a solution of 1% gelatine in 10% sodium chloride for their tannin determination in cider. They determined the total tannoids (T) by the Neubauer-Loewenthal procedure, then precipitated the true tannin in a buffered solution with 2.0% cinchonine sulfate, and determined the non-tannin polyphenols (< ) in the centrifugate. T — V thus equals the true tannins. Since the tannin content decreases with time, Fessler (1947) noted that the age of the sample should be stated along with the tannin results. Rentschler and Hauser (1950) precipitated the catechin tannins in a hot acid solution with formaldehyde, filtered, washed with alcohol and ether, dried and weighed. The anthocyanin pigments were reported not to interfere. 

The method of Manabe (1982) for total tannin determination works well with astringent fruits such as Hiratanenashi, but not with non-astringent fruits such as... 

Hundt H K L, Roux D G 1978 Condensed tannins Determination of the point of linkage in terminal (-f-)-catechin units and degradative bromination of 4-flavanyl-flavan-3,4-diols. J Chem Soc Chem Commun 696-698... 

FIGURE 4.17 MPFS for tannin determination in beverages. C carrier (H2O) D spectrophotometric detector MP micropump Rl Folin-Denis reagent R2 NaOH RC reaction coil S sample V three-way solenoid valve and W waste. 

The quantity and organization of the mucosa are critical determinants of GIT functions. Feeding chicks and rats diets with tannins causes mucosal atrophy and villus shortening, with liver damage, and decreases growth and survival... 

Other analytical assays proposed for the quantification of hydrolyzable tannins in plant materials include the rhodanine assay for the estimation of gallotannins (Berardini and others 2004) and sodium nitrate for the quantitative determination of ellagic acid (Wilson and Flagerman 1990). 

Hartzfeld PW, Forkner R, Hunter MD and Hagerman AE. 2002. Determination of hydrolyzable tannins (gal-lotannins and ellagitannins) after reaction with potassium iodate. J Agric Food Chem 50(7) 1785—1790. 

Flavan-3,4-diols FIavan-3,4-diols, also known as leucoanthocyanidins, are not particularly prevalent in the plant kingdom, instead being themselves precursors of flavan-3-ols (catechins), anthocyanidins, and condensed tannins (proanthocyanidins) (see Fig. 5.4). Flavan-3,4-diols are synthesized from dihydroflavonol precursors by the enzyme dihydroflavonol 4-reductase (DFR), through an NADPH-dependent reaction (Anderson and Markham 2006). The substrate binding affinity of DFR is paramount in determining which types of downstream anthocyanins are synthesized, with many fruits and flowers unable to synthesize pelargonidin type anthocyanins, because their particular DFR enzymes cannot accept dihydrokaempferol as a substrate (Anderson and Markham 2006). 

I. Fecka and W. Cisowski, TLC determination of tannins and flavonoids in extracts of some Erodium species using chemically modified stationary phases. J. Plan. Chromatogr.—Mod. TLC 15 (2002) 429-432. 

Abstract Recently, the interest on biomaterials and especially in tannins was growing and some attractive results were obtained in the adsorption of some metals by tannin adsorbents. Tannins are widely distributed in nature and have multiple adjacent polyhydroxyphenyl groups in their chemical structure which have extremely high afiSnity for heavy metal ions. This study will describe how tannin can be used as an effective zinc and lead sorbent by the use of tannin resins. Batch method was used in the experiments in which pH profde, adsorption time, adsorbent/liquid ratios, initial concentration of metal ions, adsorbent amount and temperature were investigated to determine binding properties of adsorbent for the Zn(II) and Pb(ll) ions. 

In this work, sumac leaves will use to remove Cu + ions in aqueous solutions. Firstly the tarmins will extract from leaves and determine tannin contents. Then, binding properties of leaves for the Cu " ions will be investigated. 

A calibration graph 3-15 ppm TA concentration range was constructed and the content of tannins in sumac leaves was determined by the Folin-Ciocalteu method. 

Leaves of Sumac were used for removal of ions in aqueous solution. Tannins were extracted from the leaves of sumac by extracting with 70% (v/v) acetone-water solution. For the total tarmin determination Folin-Ciocalteu method was used and tannin content was found 27%. Various adsorption parameters for the effective removal of Cu + ions by using sumac leaves as an adsorbent from aqueous solutions were studied and optimized. 

Price ML, Butler LG (1977) Rapid visual estimation and spectrophotometric determination of tannin content of sorghum grain. J Agric Food Chem 25 1268-1273... 

Zucker, W. V. (1983). Tannins does structure determine function An ecological perspective. AmericanNaturalist 121,335-365. 

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