Determination of lead in food additives

　　1. Effect of structure and molecular weight of the viscosity

　　Thickeners are generally in the solution is easy to form a mesh structure or more substances having a hydrophilic group, it has a high viscosity. With the chance of increasing the relative molecular mass, form a network structure is also increased, so the larger the molecular weight of the thickener, the viscosity is greater.

　　2. The impact of concentration on the viscosity

　　Thickener concentration, increased risk of interaction; increased adhesion of water molecules, the viscosity increases.

　　Effect 3.pH viscosity values

　　The pH value of the relationship between media and thickeners and viscosity stability very closely;

　　In the high acidity of soft drinks, yogurt and other foods, the side chain should be selected larger or more, and larger steric hindrance, and less prone to hydrolysis of propylene glycol alginate and xanthan gum and the like;

　　CMC and sodium alginate and the like are advised to use in near neutral soy milk and other foods.

　　4. Effect of temperature on the viscosity

　　Usually ── As the temperature increases, the viscosity of the solution is reduced;

　　Exception ── small amount of sodium chloride is present, xanthan gum viscosity in the range of -4 ~ + 93 ℃ little change.