膠原蛋白大量存在脊椎動物中，動物性蛋白質約 30%是由膠原蛋白構成，含量會隨著年紀及季節的不同而改變。膠原蛋白是一種纖維蛋白可分為28 型：第I 型至第XXVIII 型，主要分佈在細胞外之外基質，其穩定器官與結締組織以維持它們的結構完整性。膠原蛋白提取製品已廣泛應用於醫藥、保健食品加工與化妝保養品等眾多領域，但由於動物疫情持續爆發，使其源自於陸生
動物的膠原蛋白之安全性受到質疑，因此以水生動物如淡水、海水魚與軟體動物類之膠原蛋白作為替代來源受到高度重視，而不同生物來源與不同組織所得膠原蛋白之生物化學與物理相關特性，如熱穩定性會有所差異。另外，近十年來膠原蛋白與明膠酵素水解物更受到重視，其具有不同特性與功能性可符合不同顧客之需求並已開發多種商品，因此本篇將探討不同水生動物來源所得膠原蛋白之特性與其水解物機能性之應用。

Collagen is the most abundant protein in vertebrates and constitutes about 30% of total proteins. It provides the major structural and mechanical support to tissues. There are at 28 different types of collagen, named from type I to type XXVIII, which varies considerably in their complexity and diversity of their structure.Collagen has been widely used in fields including foods, medicines,cosmetics and tissue engineering due to its excellent biocompatibility or biodegradability. Generally, the main sources of type I collagen are limited to those of bovine or porcine dermis. However, bovine spongiform encephalopathy (BSE), transmissible spongiform encephalopathy (TSE) and foot and mouth disease (FMD) are threat to collagen products based on these materials. As a consequence, the alternative sources of collagen, especially from aquatic animals including freshwater and marine fish and mollusks have received increasing attention. Biochemical properties of collagen, such as
thermal stability, might be different between the different sources. On
the other hand, enzyme-hydrolyzed collagen plays an increasingly important role in various products and applications. Its different
properties and functionalities benefit the end consumer now in ways which were not present ten years ago. Over the past decade, a large number of studies have investigated enzymatic hydrolysis of collagen or gelatin for the production of bioactive peptides. The aim of this review was to characterize collagen from aquatic animals and to investigate the functionalities of the enzyme-hydrolyzed collagen.