幾丁質是由N-acetyl-D-glucosamine單位以β-1,4-鍵結而成的多醣體,除去部份或全部乙醯基的聚合物則稱為幾丁聚醣。幾丁質廣泛地存在於自然界中,例如海洋無脊椎動物,昆蟲外殻以及藻類、真菌和酵母菌等菌體的細胞壁中。幾丁質和幾丁質和幾丁聚醣本身皆具有一些特殊的功能性,利用這些功能特性或加以修飾常可應用於食品、醫藥、化粧品、生化及廢水處理等工業上。目前最常被用來作為廢水處理凝聚劑,控制食品起泡性、改良食品黏性和保水性的增稠劑以及果汁和啤酒的澄清劑。最近有關幾丁質、幾丁聚醣及其衍生物在食品以及其他工業上的發展與應用包括: 1.食品:膳食纖維、防腐劑、食品香味增強劑和膠囊化香料或營養素。 2.醫藥:徐放劑、抗凝血劑、低血膽固醇劑、促進傷口癒合的療傷藥和藥物膠囊材料。 3.生化:固定化酵素擔體、耐鹼性逆滲透膜和陰離子交換樹脂。 4.化粧品:乳化安定劑和頭髮定型液。
Chitin, poly-β-(1-4-N-acetyl-D-glucosamine, a cellulose-like biopolymer, is distributed widely in nature (e.g. in marine invertebrates, insects, fungi and yeasts) and chitosan, (2-deoxy-2-aminog-lucosè polymer), is a deacetylated chitin. Chitin and chitosan which encompass a great of functional properties have many applications in food, pharmacy, cosmetic, biochemistry and waste water treatment. In the past, they were usually used as coagulant in the treatment of waste water treatment, thickener to control foam, improve cling and moisture uptake in foods as well as clarifying agent of. juice and beer, etc. Recent developments in chitin, chitosan and their derivatives have led to amplify their applications in food and other industries as follows: 1. Food: dietary fiber, preservative, flavor extender, and flavor or nutrient encapsulation material. 2. Pharmacy: wound-healing promoting agent in form of woven fabrics or bandages, drugs release controlling agent, blood anti-coagulant, pharmaceutical table, and hypocholesterolemic agent. 3. Biochemistry: immobilized enzymes, anion exchange resin, and alkali resistant reverse osmosis membrane. 4. Cosmetic: emulsion stabilizer, and hair setting lotion.