MECHANISMS OF PROTEIN PRECIPITATION FOR 2 TANNINS, PENTAGALLOYL GLUCOSE AND EPICATECHIN(16)(4-]8) CATECHIN (PROCYANIDIN)

Citation
Ae. Hagerman et al., MECHANISMS OF PROTEIN PRECIPITATION FOR 2 TANNINS, PENTAGALLOYL GLUCOSE AND EPICATECHIN(16)(4-]8) CATECHIN (PROCYANIDIN), Journal of agricultural and food chemistry, 46(7), 1998, pp. 2590-2595
Citations number
42
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Food Science & Tenology",Agriculture,"Chemistry Applied
ISSN journal
0021-8561
Volume
46
Issue
7
Year of publication
1998
Pages
2590 - 2595
Database
ISI
SICI code
0021-8561(1998)46:7<2590:MOPPF2>2.0.ZU;2-E
Abstract
The precipitates that form when purified pentagalloylglucose or a puri fied procyanidin [epicatechin(16) (4-->8) catechin; EC16-C] are mixed with bovine serum albumin were quantitatively analyzed. EC16-C isa mor e efficient protein precipitating agent than pentagalloylglucose on a molar or a mass basis. EC16-C precipitates protein independently of te mperature and presence of organic solvent. Precipitation by pentagallo ylglucose increases as temperature is increased and decreases when alc ohols are present. When tannin is in excess, up to 40 mol of pentagall oylglucose is bound per male of protein precipitated, but only 20 mol of EC16-C is bound per mole of protein precipitated. The data support different models of precipitation for the two types of tannin: pentaga lloylglucose, which is very nonpolar, precipitates by forming a hydrop hobic coat around the protein, whereas the much more polar EC16-C form s hydrogen-bonded cross-limbs between protein molecules.