The Tuna Fishing Industry: A New Outlook on Fish Protein Hydrolysates Herpandi, N. Huda, Rosma, A. and Wan Nadiah W.A. Abstract: Tuna (Thunnus spp.) and tuna-like species are signiﬁcant sources of food and thus play a very important role in the economy of many countries. More than 48 species of tuna swarm the Atlantic, Indian, and Paciﬁc Oceans, and the Mediterranean Sea. The annual global production of tuna has undergone a marked increase from less than 0.6 million metric tons in 1950 to almost 4.5 million metric tons in 2007. Tuna generally is processed as raw ﬁsh ﬂesh and marketed as loins/steaks or as a canned food. In the tuna canning process, only about one-third of the whole ﬁsh is used. Thus, the canning industry generates as much as 70% solid wastes from original ﬁsh materials. This waste consists of muscle (after loins are taken), viscera, gills, dark ﬂesh/muscle, head, bone, and skin. Conventionally, these protein-rich by-products from the tuna industry are processed into low market value products, such as ﬁsh meal and fertilizer. However, a promising alternative use of these by-products is as functional food ingredients. Fish protein hydrolysate (FPH), which is obtained through hydrolysis of tuna waste, can be used as an ingredient in food industries to provide functional effects such as whipping, gelling, and texturing properties. Recently, FPH was found to be a potential source of antioxidants (such as peptides with anticancer properties), antianemia compounds, and components for use in microbial growth media. This article is intended to summarize the existing knowledge about FPH, highlight some pertinent information related to the tuna ﬁshing industry, and provide a new outlook on the production and applications of FPH. Introduction Tuna (Thunnus spp.) and tuna-like species have long been known as a main commodity of ﬁsheries. The principal market of tunas frequently is divided into tropical tunas, such as bigeye (Thunnus obesus), skipjack (Katsuwonus pelamis), and yellowﬁn tuna (T. albacares) and temperate tunas such as albacore (T. alalunga), Atlantic blueﬁn tuna (T. thynnus), Paciﬁc blueﬁn tuna (T. orientalis), and southern blueﬁn tuna (T. maccoyii). In addition to the principal market tuna, many other types of tuna are more neritic and live in seas over the continental shelf (for example, longtail tuna (T. tonggol), blackﬁn tuna (T. atlanticus), and black skipjack tuna (Euthynnus lineatus). Important tuna-like species that are caught in recreational and sport ﬁsheries include billﬁshes (Istiophoridae), king mackerels (Scomberomorus cavalla), and butterﬂy kingﬁsh (Gasterochisma melampus). They swarm in oceans all over the world (Majkowski 2007). The main internationally traded forms of tuna are raw material for canning (fresh, frozen, and frozen precooked loins), tuna for direct consumption (fresh/chilled and frozen), and canned tuna MS 20091146 Submitted 1/27/2011, Accepted 3/10/2011. Authors Herpandi and Huda are with Fish and Meat Processing Laboratory, Food Technology Pro- gramme, School of Industrial Technology, Univ. Sains Malaysia, Minden 11800, Penang, Malaysia. Authors Rosma, A. and Wan Nadiah W.A. are with Bioprocess Technology Programme, School of Industrial Technology, Univ. Sains Malaysia, Minden 11800, Penang, Malaysia. Author Herpandi is also with Fisheries Product Technology Programme, Sriwijaya Univ., South Sumatra 30662, Indonesia. Direct inquiries to author Huda (E-mail: nrlhd@usm.my). (solid pack, chunks, ﬂakes, and grated). Demands for tuna have gradually changed over time, beginning with the birth and growth of the tuna canning industry. Any species and any size of tuna ﬁshes can be used to produce canned tuna. When cold storage systems were introduced, the tuna market expanded to include sashimi, which is raw ﬂesh ﬁsh that is a traditional delicacy in Japan (and now also in other countries). Sashimi requires select species and large-sized tunas (such as bigeye and blueﬁn tunas). For this reason, high-quality tuna is classiﬁed as sashimi-grade tuna (FAO 2010a). According to Catarci (2005), international trading of tuna for noncanning purposes has been very proﬁtable in the last 2 decades: it grew from about 200000 metric tons worth US$850 million in 1989 to 292000 metric tons worth US$1.7 billion in 2001. These data are estimates based on imports of all fresh and chilled tunas and imports of frozen blueﬁn and bigeye tuna. Japan is the main world market for tuna for direct consumption (as sashimi). The Japanese mainly process sashimi from tuna, marlins, and yellowtail (Seriola quinqueradiata). The most expensive sashimi is made from Atlantic, Paciﬁc, and southern blueﬁn tuna. Because only the white meat of tuna is used in canning or sashimi, the tuna industry generates a large amount of waste or by-products. Guerard and others (2002) reported that solid wastes generated from the processing industry are composed of muscle (after loins are taken), viscera, gills, dark ﬂesh/muscle, head, bone, and skin, and these wastes can constitute as much as 70% of the original material. Sutanbawa and Aknes (2006) reported that pro- cessing discards from the tuna canning industry are estimated at 450000 million tons per year. c  2011 Institute of Food Technologists ® doi: 10.1111/j.1541-4337.2011.00155.x Vol. 10, 2011  Comprehensive Reviews in Food Science and Food Safety 195