食品添加剂 增稠剂课件.ppt

Chapter 10. Thickeners（增稠剂）;V. Brief introduction to common thickeners** 常见增稠剂简述 ? agar（琼脂） ? carrageenan（卡拉胶） ? sodium alginate（海藻酸钠） ? pectin（果胶） ? xanthan gum（黄原胶） ? CMC（羧甲基纤维素）; ? Thickeners may be defined as water-soluble macromolecules that possess the ability to contribute viscosity or gelling ability to their dispersions.They are also called food gums. Their solutions are called food hydrocolloid. (? ) 增稠剂是亲水性大分子，可以大幅增加体系的粘度或者形成凝胶，它们也叫食品胶。;Viscosity is ? 粘度，粘、稠、不易搅动;Gel is ?; ? Thickeners are hydrocolloids（亲水胶体） (mainly polysaccharides，多糖) with high molecular weight and containing many hydrophilic groups（亲水基团） such as hydroxyl groups （羟基）, carboxyl groups（羧基） and amino groups（氨基),Sulfate, phosphate as well 硫酸酯基，磷酸酯基;What make a thickener ?增稠剂的分子特征？;Ⅱ Varieties and Classification ;Natural thickeners; Origin (? ); Natural gums;Continued ;(2) According to their chemical structure (? ) ;Tamarind flower and seed;;(3)According to their main functions(? ) ;Thickeners can be classified into thickeners and gelling agents (胶凝剂) thickeners: the main function is to thicken or impart viscosity（粘度） to aqueous solutions水. gelling agents: who possess the ability to convert water from a flowable liquid to a demoldable（可塑性的） solid or gel（凝胶）. 把水转化成可塑性的固体或者凝胶 ;Typical thickeners include modified starch（改性淀粉）, guar gum, locust bean gum, xanthan gum, arabic gum ,CMC.;? Branched（支链） especially highly branched polysaccharides are much easier to dissolve in water than linear especially uniformly linear ones. They can even dissolve in cold water. Such is the case for xanthan gum, guar gum, and arabic gum. 支链的多糖比直链的容易溶于水，它们甚至可溶于冷水，如黄原胶，瓜儿豆胶和阿拉伯胶;? Charged polysaccharides also readily dissolve in water. For example, CMC and sodium alginate are cold-water soluble.离子型容易溶于水，如羧甲基纤维素和海藻酸钠可溶于冷水;Viscosity depends on the structure, molecular weight of thickeners (internal factors), the concentration, pH value and temperature of thickener solutions, ionic strength, sh