Formation of complexes between protein and tannic acid

Abstract

Tannic acid and protein interact to form soluble and insoluble complexes, and the latter are favored by a pH near the isoelectric point of the protein and an excess of tannic acid. As the concentrations decrease, higher ratios of tannin to protein are possible in soluble complexes. The number of sites on a gelatin molecule occupied per tannin molecule decreases as the tannin concentration increases. and this is accompanied by a decrease in the apparent equilibrium constant of binding between the tannic acid and the gelatin. Bonding between gelatin and tannin molecules is strong, particularly when a greater weight of gelatin than tannin is present; hence, there is relatively little unbound tannin in such soluble systems. Tannic acid is heterogeneous with regard to its ability to precipitate gelatin. Under no conditions could all the added tannic acid be precipitated by gelatin.in understanding of the interactions between tannins and proteins is of importance for effective control and *removal of haze in natural beverages. Much of our knowledge of these reactions comes from work in the field of leather research (Gustavson, 1956); however, the conditions

Phytochemical and antibacterial properties of <i>Diodia scandens</i> and <i>Phyllanthus amarus</i> on staphylococci isolated from patients in tertiary hospitals in Nigeria

“…This study showed synergism on the combined concentrations of the plant extracts under study at a lower concentration, with FICI ≤ 0.5, which was in consonance with an earlier report (though not FIC determined) by the same author (Ojo et al 2013a) (see Figure 1). Cowan (1999) Britto et al 2013;Tamil et al 2010;Van-Burden & Robinson 1981;Young & Greaves 1940;Zabri et al 2008) as in this study. By implication, the combination of these medicinal plants produces a greater efficacy in the treatment of staphylococcal wound infection as regularly experienced in orthodox medicines.…”

Physiological and Biochemical Changes in Cucurbita moschata Duch. Ex. Poir Inoculated with a Nigerian Strain of Moroccan Watermelon Mosaic Virus (MWMV): Lagenaria breviflora Isolate

“…Alkaloids were determined using, Harbone (1973) method, tannins (Van Buren andRobinson, 1969). Vitamins and minerals were determined by atomic absorption spectrophotometer (Pye Uniam SP8-190, Spec.…”

Phytochemical Investigation, Gc-MS Profile and Antimicrobial Activity of a Medicinal Plant Ruta Graveolens L. From Ethiopia

“…The quantitative determination of tannin in Rue sample was performed as per protocol [15]. Briefly, 500 mg of the dried extract was dissolved in 50 ml of distilled water in a screw caped conical flask and allowed to shake for 1 h. Approximately 5 ml of filtrate was mixed with 2 ml of 0.1 M FeCl3 in 0.1 N HCl and 0.008 M potassium ferrocyanide.…”