The Tuna Fishing Industry: A New Outlook on Fish Protein Hydrolysates

Tuna (Thunnus spp.) and tuna-like species are significant sources of food and thus play a very important rolein the economy of many countries. More than 48 species of tuna swarm the Atlantic, Indian, and Pacific Oceans, and theMediterranean Sea. The annual global production of tuna has undergone a marked increase from less than 0.6 millionmetric tons in 1950 to almost 4.5 million metric tons in 2007. Tuna generally is processed as raw fish flesh and marketedas loins/steaks or as a canned food. In the tuna canning process, only about one-third of the whole fish is used. Thus, thecanning industry generates as much as 70% solid wastes from original fish materials. This waste consists of muscle (afterloins are taken), viscera, gills, dark flesh/muscle, head, bone, and skin. Conventionally, these protein-rich by-productsfrom the tuna industry are processed into low market value products, such as fish meal and fertilizer. However, a promisingalternative use of these by-products is as functional food ingredients. Fish protein hydrolysate (FPH), which is obtainedthrough hydrolysis of tuna waste, can be used as an ingredient in food industries to provide functional effects such aswhipping, gelling, and texturing properties. Recently, FPH was found to be a potential source of antioxidants (such aspeptides with anticancer properties), antianemia compounds, and components for use in microbial growth media. Thisarticle is intended to summarize the existing knowledge about FPH, highlight some pertinent information related to thetuna fishing industry, and provide a new outlook on the production and applications of FPH.