Gelatin produced from fish processing by-product is the most potential alternative source of gelatin. They have biological activities, particularly antioxidant, antihypertensive, and reduce type 2 diabetic risk. This paper reviews the mechanisms of fish gelatin hydrolysates for those human diseases being discussed in recent studies. Based on the review, mostly, skin and bone are used as sources of fish-based gelatin in which about thirty percent comes from the weight of total fish. Some species have been analysed based on their bioactivities, including Tuna, Nile tilapia, Amur sturgeon, Pangasius catfish, Cod, Blacktip shark, Salmon, Halibut, and Tilapia fish. In short, the antioxidant mechanism of this fish-based gelatin is by scavenging and neutralizing the radicals. The antihypertensive mechanism is by inhibition of Angiotensin-Converting Enzyme (ACE) activity. Whilst the mechanism to reduce type 2 diabetes is by inhibiting dipeptidyl peptidase IV (DPP-IV) action.
Keywords: ACE, antidiabetic, antihypertensive, antioxidant, bioactive peptide, DPP-IV inhibitor.