<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Makkar, H P S</style></author><author><style face="normal" font="default" size="100%">Singh, B</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Distribution of condensed tannins (proanthocyanidins) in various fibre fractions in young and mature leaves of some oak species</style></title><secondary-title><style face="normal" font="default" size="100%">Animal Feed Science and Technology</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">1991</style></year></dates><publisher><style face="normal" font="default" size="100%">ELSEVIER SCIENCE BV</style></publisher><pub-location><style face="normal" font="default" size="100%">PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS</style></pub-location><volume><style face="normal" font="default" size="100%">32</style></volume><pages><style face="normal" font="default" size="100%">253-260</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The distribution of proanthocyanidins (PAs), using HCl-butanol reagent, was studied in various fractions in young and mature leaves of five oak species, Quercus incana, Quercus semecarpifolia, Quercus serrata, Quercus ilex and Quercus glauca. In leaves of all the oak species studied, PAs expressed as A550 nm g−1 whole leaf, neutral detergent fibre (NDF) or acid detergent fibre (ADF) were higher in mature leaves. When the PAs were expressed as a percentage of the total PAs, the PAs in NDF were lower in mature leaves except for Q. ilex, and in ADF were lower in young leaves. Significant proportions of total PAs were present in NDF and ADF; the values ranged from ∼ 7 to 28% in NDF and from 3 to 21% in ADF. Similarly, PAs which could not be extracted using 50% aqueous methanol varied from 10 to 55% of the total PAs. These observations suggest that there is a need to recognise the importance of these tannins as well as those which are extractable. The PAs in both NDF and ADF had a significantly positive correlation with total and unextracted PAs and NDF, and with ADF, hemicellulose, cellulose and lignin their correlations were positive but not significant. The results are discussed in relation to maturity of the leaves and their likely contribution towards producing artefacts or errors when using the detergent system of feed analysis.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Makkar, H P S</style></author><author><style face="normal" font="default" size="100%">DAWRA, R K</style></author><author><style face="normal" font="default" size="100%">Singh, B</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">TANNIN LEVELS IN LEAVES OF SOME OAK SPECIES AT DIFFERENT STAGES OF MATURITY</style></title><secondary-title><style face="normal" font="default" size="100%">JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">CONDENSED TANNINS</style></keyword><keyword><style  face="normal" font="default" size="100%">Tannins</style></keyword><keyword><style  face="normal" font="default" size="100%">TOTAL PHENOLS</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1991</style></year></dates><publisher><style face="normal" font="default" size="100%">JOHN WILEY &amp; SONS LTD</style></publisher><pub-location><style face="normal" font="default" size="100%">BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD</style></pub-location><volume><style face="normal" font="default" size="100%">54</style></volume><pages><style face="normal" font="default" size="100%">513-519</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Total phenolics, condensed tannins, degree of polymerisation, protein precipitation capacity, protein precipitable phenolics and specific activity (protein bound per unit tannins) were determined in the leaves of four oak species at different stages of maturation (4 days old to 1 year old). The content of total extractable phenols was higher in younger leaves in Quercus ilex Linn, Quercus semecarpifolia Sm and Quercus serrata Roxb, whereas in Quercus glauca Thunb the content was higher in the mature leaves. In all species studied, condensed tannins increased with maturation. Protein precipitation capacity had a trend similar to that of total phenols. In Q serrate and Q semecarpifolia the apparent degree of polymerisation increased, and the content of protein precipitable phenolics and specific activity decreased as the leaves matured. The decrease in protein precipitation capacity with maturation in these two species may be explained by both the decrease in the content and the change in the nature of phenols capable of binding proteins. Protein precipitation capacity was not detectable in Q ilex leaves. Protein precipitation capacity in the mature leaves decreased in the order of Q serrata &gt; Q semecarpifolia &gt; Q glauca &gt; Q ilex.</style></abstract></record></records></xml>