Tannin content

Com, wheat, and rice are the most desirable common grains and are used extensively ia pet foods. Oats and barley often tend to have excess fiber, which can be objectionable. However, barley is a preferred grain for moisture absorption and form ia caimed foods because the turgid white form is desired ia some canned dog foods. Milo has enormous variations ia tannin content which can influence digestibiUty and acceptabiUty, thus limiting its use ia pet foods (see Wheat and other cereal grains). 

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. 

Rhus coriaria L. is a shrab, which reaches 3M p in high in the wild. Its powdered leaves were used as a tanning agent for its high tannin content [10]. Tannins are found in the leaves, fmit, barks, roots and wood of trees. They can be classified into two groups condensed tannins and hydroly sable tannins [11]. The co-occurrence of both kinds of tannins in the same plant or plant tissue is often observed [12]. The main compounds present mRhus coriaria L. are hydrolysable gallatonnins. 

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. 

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... 

Chernayeva, G. N., Dolgodvorova, S., and Peryshkina, Y. (1982). Seasonal dynamics of tannin content in European white birch bark. RastitielniiResurci 18,63-66. 

A The variety with the higliest tannin content had the most nitrogen and least fibre. B CR depressed by tannins irrespective of other factors. 

Kantar, F., Pilbeam, C.J., and Hebblethwaite, P.D., Effect of tannin content opf faba bean Vida faba) seed on seed vigour, germination and field emergence, Ann. Appl. Biol, 128, 85, 1996. 

Feeny (13) attempted to resolve this dilemma by proposing that forest trees may have developed a particularly recalcitrant defense, one which even insects could not overcome in hundreds of generations. His suggestion was that protein-complexing polyphenols, or tannins, could provide such protection. However, there are many insects which feed preferentially on high-tannin content tissues (14, ), and specific adaptations exist which can nullify or reduce the digestion inhibition effects of tannins (16). ... 

Hence tannin-tolerant insects with elevated gut pH s may be relatively resistant to these pathogens. According to theory (69,70), early successional plants should have low tannin contents and their herbivores should have lower gut pH values... 

Tannins, another group of phenolic substances, are known for their sensory effects on wine. In addition to their influence on the body of wines, tannins produce an astringent taste. Amerine and Joslyn (2) reported that the usual range of tannin content for white wines is from 0.01 to 0.04% and from 0.10 to 0.20% for red table wines. The threshold for tannin was reported as 0.10 gram/100 ml for a white table wine and 0.15 in a red table wine (137). Other studies have reported that tannin affects the detection levels for sweetness and tartness in wines (18, 138, 139). In addition to their influence on taste, tannins are responsible, in... 

These tables show larger differences between years than between varieties. The comparison between the two vineyards, both cultivated by traditional methods, does not show significant differences. These experiments demonstrate the importance of the year and climatic conditions on the anthocyanin and tannin content. These variations are much more important than those of other chemical constituents (sugars and acids). 

The glycosidic anthocyanins are almost completely precipitated with red wines of a few months age and normal tannin content. However, with young wines made from the same grapes, a ros6 wine with only 713 mg GAE/liter total phenol gave 311 mg GAE/liter as not-precipitated nonflavonoid, and with increasing levels of total phenol in red wines to... 

Table XIII. Total Phenol, Tannin, and Non tannin Content of Wines From the Data of Mitjavila et al. (37)...

This shift from wood to stainless steel cooperage has been general and a factor in changing production practices around the world, particularly for red wines. A wine well protected from oxidation in an impervious tank will not change rapidly in tannin content. If it was vinified so as to be too tannic for acceptance by the consumer, it is likely to remain... 

Variations within a tree may be large. In one example from Q. robur, the tannin of the bark was 10.9%, sapwood 1.0%, and heartwood 7.7% at the periphery, 6.6% intermediate, and 6.6% at the center, all at the base of the tree which was 50 cm in diameter and 90 years old (31). At the top of the same trunk (34-cm diameter, 71 years) the same respective tissues had tannin contents of 5.7, 0.8, 5.3, 4.6, and 4.7%. This pattern of higher extractable tannin in the heartwood nearest the sapwood and lower near the pith, higher as the tree gets older, and higher in the base of the tree than the top is general (21). 

Benefits The caffeine content makes guarana a strong central nervous system stimulant. It is traditionally used as a tonic for fatigue and to allay hunger and thirst. It also has short-term diuretic effects. The tannin content gives guarana an astringent effect and it has been used to treat diarrhoea. 

The tannin content of different raw materials varies considerably, according to the quality and origin, as is seen from the examples quoted in the following table (XXXVIII), which gives also the soluble non-tannins and the reducing sugars. 

Faba beans contain several ANFs such as tannins, protease inhibitors (vicin/ convicin) and lectins. Use of low-vicin/convicin cultivars may allow substantial levels of faba beans to be included in poultry diets (Danner, 2003). The levels of trypsin inhibitor and lectin activities are low compared with other legume seeds and do not pose problems in poultry diets when faba beans are incorporated into diets at the levels shown below. Of most concern for poultry is the tannin fraction, which has been shown to depress digestibility of the protein and AA (Ortiz et al., 1993). Tannins in whole faba beans are associated with the seedcoat (testa), and the tannin content is related to the colour of the seedcoat (and flowers). Tannins are lower in white than in the colour-seeded varieties. 

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