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Yam tuber mucilage as a candidate substance for saliva substitute: in vitro study of its viscosity and influences on lysozyme and peroxidase activities
Author(s) -
Kho HongSeop,
Park MoonSoo,
Chang JiYoun,
Kim YoonYoung
Publication year - 2014
Publication title -
gerodontology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.7
H-Index - 54
eISSN - 1741-2358
pISSN - 0734-0664
DOI - 10.1111/ger.12000
Subject(s) - lysozyme , mucilage , lactoperoxidase , saliva , peroxidase , viscosity , chromatography , viscometer , food science , carbohydrate , biochemistry , chemistry , enzyme , botany , materials science , biology , composite material
Objective To investigate the viscosity of yam tuber mucilage ( YTM ) and its effects on lysozyme and peroxidase activities in solution phase and on surface phase. Methods Two kinds of YTM were extracted, one containing both protein and carbohydrate and the other containing mainly carbohydrate. Hen egg‐white lysozyme and bovine lactoperoxidase were used as lysozyme and peroxidase sources, respectively. Viscosity was measured with a cone‐and‐plate digital viscometer. Lysozyme activity was determined using the turbidimetric method, and peroxidase activity was determined using the N bs SCN assay. Hydroxyapatite beads were used as a solid phase. Results The viscosity values of YTM followed a pattern of a non‐ N ewtonian fluid. The carbohydrate concentration affected the viscosity values at all shear rates, while the protein concentration affected the viscosity values at low shear rates. It could be suggested that YTM composed of 1.0 mg/ml protein and 1.0 mg/ml carbohydrate has viscosity values similar to those of unstimulated whole saliva at shear rates present at routine oral functions. Hydroxyapatite‐adsorbed YTM significantly increased the adsorption and subsequent enzymatic activities of lysozyme, but not those of peroxidase. Conclusions Yam tuber mucilage has viscoelastic properties similar to those of human saliva and enhances the enzymatic activity of lysozyme on hydroxyapatite surfaces.