Fish waste is a rich source of proteins, fats and minerals. Fish protein hydrolysate is produced by enzymatic treatment of fish waste. Protein hydrolysate can be used to prevent the protein degradation of fish during freezing. Keratin and collagen present in fish and livestock waste can be converted into valuable products by enzymatic hydrolysis (Ohba et al., 2003).
Collagen present in yellow tail fish is used as raw material for the synthesis of peptides and protein hydrolysate, which can be used as food ingredient. Bioactive peptides and enzymes obtained from fish waste is used for fish sauce preparation and as fish feed (Gildberg, 2004). Protein hydrolysates are produced by auto-hydrolysis of fish waste and are used to produce peptone hydrolysate which is used for preparation of microbial growth media to support the growth of lactic acid bacteria for the production of bacteriocin (Vanquez, Gonzalez, & Murado, 2004). Moreover, waste of different fish varieties including Pink perch, Indian mackerel and Indian oil sardine can also be used for the extraction of unsaturated fatty acids (Amit, Swapna, Bhaskar, & Baskaran, 2012). There are several uses of fish by-products for example fish mince, fish gelatin and different fish nutraceuticals ingredients, fish concentrates as food ingredient and fish meal.
A good yield of protein can be recovered from the fish waste in lake water by alkaline extraction process (Batista, 1999). Organic waste from the fish market is processed to recover the amino acids and for produc-tion of organic acids. Sub-critical waste water hydrolysis of fish meat is source of valuable products (Yoshida, Terashima, & Takahashi, 1999).
Fish waste can be potentially used for animal and poultry feeding (Hammoumi, Faid, El-Yachioui, & Amarouch, 1998). Sardine fish waste can be converted into high protein animal feed by fermentation using biological culture of Lactobacillus plantarium and Saccharomyces species. Use of pure culture for fermentation involves in transformation, preservation and quality improvement of the final product (Faid, Zouiten, Elmarrakchi, & Achkari-Begdouri, 1997). Discarded fish waste and under-exploited fish species can be used for development of restructured fish products (Borderias & Mateos, 1996).
Fish waste has the potential of fermentation media to produce anti-bacterial compounds by lactic acid producing bacteria (Tahajod & Rand, 1996). Peptones for media preparation are attained from beef, horse and pig meat but it is approved that fish waste is the best good source (Skorupa & Sikorski, 1993). Different flavoring products can be prepared from the shrimp by-products such as shrimp sauce. Kim, Shahidi, and Heu (2003) reported the characteristics of sauces prepared from shrimp by-products. They also reported that shrimp by-products can also be used to prepare good quality salt fermented sauces. Fish oil can also be prepared from fish by-products; its quality and stability have been studied by Aidos, A-van-der, Boom, and Luten (2001).
Fish collagen is very important by-product of fish processing in-dustry as it is a source of fish gelatin. Fish production has approached to 100 million metric tons per annum; 28% is used to produce fish oil and fish meal. Fish waste containing high oil and excessive bone content is processed into valuable products which are used as animal feed or in-dustrial ingredients. Seafood waste material is processed for recovery of different chemical components. Processing and utilization of fish-by products is an auspicious area of research. Crab shell and shrimps are
source of chitosan which is widely used in the cosmetic and pharmaceu-tical industries (Arvanitoyannis & Kassaveti, 2008a, 2008b). Chitosan is also used to remove proteinaceous matter in processing industries. Chitosan coagulates the proteinaceous material and removes it in food processing operations (Knorr, 1991).
In many countries absence of protenaceous material in waste water of municipal sewer system is mandatory and chitosan is used to remove this material. Moreover chitosan is used for the elimination of heavy metals from industrial effluent as non-toxic flocculent agent to treat organic wastewater. Chitosan is an antimicrobial agent and effectively kills the bacteria, fungi and yeast. It can also be used in food packaging material as food preservative because it has film forming ability as well as antimicrobial activity (Rabea, Badawy, Stevens, Smagghe, & Steurbaut, 2003). Chitosan is also used as food preservative in different ways such as incorporation of chitosan in food packaging material, direct inclusion of chitosan in food material, addition of chitosan sachets in food packages or application of chitosan based edible films or coatings. Antimicrobial activity of chitosan has been reported by different researchers in solution or film forms (Staroniewicz, Ramisz, Wojtasz-Pajak, & Brzeski, 1994). Addition of chitosan in packaging material is a type of active packaging or antimicrobial packaging (Coma, 2008).
Fish by-products are excellent source of fish oil which provides unsaturated fatty acids. Fish waste oil after ozone treatment is used as diesel fuel in diesel engines (Kato, Kunisava, Kojima, & Murakami, 2004).
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The authors of this article are
- Syed Mudabbar Hussain Shah from Department of Food Engineering. a
- Syed Shabbar Hussain Shah from Department of Soil Science. a
- Mirtab Ali from Department of Food Science & Technology. a
*a = University of Agriculture, Faisalabad.