000			03223nab a22003617a 4500
001			68131
003			MX-TxCIM
005			20251105091707.0
008			241115s1984 -us|||po p||| 00| 0 eng d
022			_a0003-021X
022			_a1558-9331 (Online)
024	8		_ahttps://doi.org/10.1007/BF02542166
040			_aMX-TxCIM
041			_aeng
100	1		_aButler, L.G. _931906
245	1	0	_aInteraction of proteins with sorghum tannin : _bMechanism, specificity and significance
260			_aUnited States of America : _bAmerican Oil Chemists' Society ; _bJohn Wiley & Sons, _c1984.
500			_aPeer review
520			_aThe grain of some varieties of sorghum contains 2% or more condensed tannin; many other varieties contain no tannin at all. Agronomic advantages, e.g., resistance to bird depredation, are associated with high-tannin sorghums, which have relatively low nutritional value for nonruminants. The biological effects of tannin are a result of its propensity for binding proteins; both hydrogen bonding and hydrophobic interactions are involved. Sorghum tannins can bind dietary proteins and reduce their digestibility. Purified digestive enzymes are inhibited by tannin, but significant inhibition in vivo is unlikely. Proteins differ greatly in their affinity for tannin. Those with highest affinity are large, have an open structure, contain no bound carbohydrate and are rich in proline. Sorghum proteins of the alcohol-soluble prolamine fraction associate strongly with tannin, are difficult to remove during tannin purification and are found combined with tannin in the indigestible residue after in vitro digestion with pepsin. On germination, the seed may sacrifice a portion of these proteins to bind the tannin that might otherwise interfere with metabolism by inhibiting seed enzymes. During seed development, tannin molecules are relatively short and do not effectively precipitate proteins; as the seed dries, tannins undergo polymerization to an average of ca. 6 flavan-3-ol units/molecule. The antinutritional effects of sorghum tannins can be eliminated by soaking the grain in dilute aqueous alkali, but not by cooking. When rats are put on high-tannin sorghum diets, their parotid glands undergo hypertrophy and produce a group of unique salivary proteins with extremely high affinity for tannin. These proteins contain over 40% proline and are devoid of sulfur-containing and aromatic amino acids. This metabolic adaption may protect rats against tannin by binding and inactivating it immediately when it enters the digestive tract.
546			_aText in English
650		7	_aInteractions _2AGROVOC _929978
650		7	_aProtein content _2AGROVOC _91222
650		7	_aSorghum _2AGROVOC _92002
650		7	_aTannins _2AGROVOC _931904
650		7	_aHydrophobicity _2AGROVOC _937278
650		7	_aDigestibility _2AGROVOC _99136
650		7	_aCarbohydrates _2AGROVOC _94730
700	1		_aDavid, J.R. _937275
700	1		_aLebryk, D.G. _937276
700	1		_aBlytt, H.J. _937290
773	0		_dUnited States of America : American Oil Chemists' Society ; John Wiley & Sons, 1984. _gv. 61, no. 5, p. 916-920 _tJournal of the American Oil Chemists' Society _x0003-021X
942			_2ddc _cJA _n0
999			_c68131 _d68123