Protein Binding and Astringent Taste of a Polymeric Procyanidin, 1,2,3,4,6-Penta-O-galloyl-β-D-glucopyranose, Castalagin and Grandinin

摘要: The objective of the present investigation was to examine oral astringency and protein-binding activity four structurally well-defined tannins, namely, procyanidin [epicatechin16(4→8)catechin], pentagalloyl glucose (1,2,3,4,6-penta-O-galloyl-β-d-glucopyranose), castalagin, grandinin, representing three main structural categories proanthocyanidins, gallotannins, ellagitannins. Astringency threshold dos/response were determined by half-tongue test using a trained human panel. Protein-binding stoichiometry relative affinity radioiodinated bovine serum albumin in precipitation or competitive binding assays. Procyanidin perceived as highly astringent compounds had relatively steep dose/response curves, but castalagin grandinin lower mass for detection. In vitro, most effective protein-precipitating agent least. Increasing temperature increa...