Colloidal stability of tannins: astringency, wine tasting and beyond

Abstract

Tannin-tannin and tannin-protein interactions in water-ethanol solvent mixtures are studied in the context of red wine tasting. While tannin self-aggregation is relevant for visual aspect of wine tasting (limpidity and related colloidal phenomena), tannin affinities for salivary proline-rich proteins is fundamental for a wide spectrum of organoleptic properties related to astringency. Tannin-tannin interactions are analyzed in water-ethanol wine-like solvents and the precipitation map is constructed for a typical grape tannin. The interaction between tannins and human salivary prolinerich proteins (PRP) are investigated in the framework of the shell model for micellization, known for describing tannin-induced aggregation of β-casein. Tannin-assisted micellization and compaction of proteins observed by SAXS are described quantitatively and discussed in the case of astgringency.

Antimicrobial Effects of Wine: Separating the Role of Polyphenols, pH, Ethanol, and Other Wine Components

“…Namely, polyphenols are highly sensitive to changes in physical–chemical properties of the medium in which they are contained. It may significantly influence their solubility, precipitation behavior as well as interactions with proteins, which in turn influence their biochemical properties and biological activity (Serafini and others 1997; Zanchi and others 2007, 2008). Supportive to this is also the finding that antioxidant activity evolution of the isolated phenolic compound was highly dependent on the solvent polarity.…”

Thermally treated wine retains antibacterial effects to food-born pathogens

“…This might in part explain why reconstitution of dealcohlized wine with water, to its initial volume before dealcoholization, resulted in lower levels of phenolics content relative to the intact wine, with corresponding decrease in antioxidative and even stronger decrease in antimicrobial activity. Supportive to this is the observation that even small changes in physical-chemical properties of hydroalcocholic solutions in which polyphenols are dissolved significantly influence their solubility, precipitation behaviour as well as interactions with proteins, which in turn influence their biochemical properties and biological activity (Serafini et al, 1997;Zanchi, Poulain, Konarev, Tribet, & Svergun, 2008;Zanchi et al, 2007).…”

Lyotropic Liquid Crystalline Phases for the Formulation of Future Functional Foods

“…Anticancer activity (breast, lung and prostate cancer) 46 Interactions with soy proteins 47 Limited bioavailability, reduced antioxidant activity through interactions with proteins 48 Berries Kaempferol Antioxidant, anti-inflammatory, antimicrobial, anticancer, cardioprotective, neuroprotective, antidiabetic activity 49 Poor water-solubility and low bioavailability (2%) 50 Broccoli, apples Tiliroside Antioxidant activity, 51 Inhibiting of neuroinflammation, 52 antihyperglycemic effects 53 Inhibitory effects on carbohydrate digestion 54 Potentilla species 53 Epigallocatechin-3-gallat (EGCG) Neuroprotective, stroke risk lowering 55 and anticancer (colon cancer) activity 36 Complex formation thorough interaction with proteins 56,57 Low bioavailability (0.2-2%) 58 Green tea…”