Shrimping industry

This area of Louisiana is one of the most productive estuaries in the continental United States in the commercial production of shrimps, menhaden (fish), oysters, crayfish (also known as crawfish and crawdads), crab, mussels, and other marine species. Louisiana is also known as a sportsman s paradise because of the recreational fishing, as well as significant commercial fishing. For example, the shrimp industry is worth over US 350 million per year in Louisiana. 

The shrimpers rallied around Tee John Mialjevich, a blustery, 300-pound, six-foot-four advocate of the shrimp industry from Louisiana, who vowed neither he nor his supporters would ever obey a government edict that required them to use the TED. We re not the culprits here, Mialjevich insisted, accusing Allen and other conservationists of a smear campaign. He said that in all his years of shrimping he had caught no more than six turtles, and that he had thrown them all back into the water alive. 

Chitin and chitosan rarely occur in a pure, easily isolated form. A substantial effort has been made to develop chemical, mechanical, and enzymatic methods to obtain purified materials (25). The usual method of obtaining chitin involves the chemical treatment of shell fish wastes from the crab and shrimp industries. The first step is to demineralize the shell with dilute hydrochloric acid at room temperature. This is followed with a deproteinization step with warm dilute caustic. This yields a partially deacetylated chitin, which may then be further deacetylated to chitosan. Figure 3 shows the underlying chitin matrix in the crab shell and its microfibrillar... 

Chitin and chitosan have been in recent years of great interest to scientists and technologists because of the variety of their commercial applications. Research and development on chitin/chitosan has been conducted in our Laboratory of Biopolymers for a number of years because of the large volume of waste shrimp shells which are derived from the evergrowing frozen shrimp industry in Vietnam [1]. 

The raw material for production of chitin in Vietnam, generally shrimp shells, are readily available as waste originating in much larger quantities and with less seasonal fluctuation in supply than in previous years because of the expansion and centralization of the frozen shrimp industry. 

Sulfur Dioxide and Sulfites. Sulfur dioxide [7446-09-5], SO2, sodium bisulfite [15181-46-1], NaHSO, and sodium metabisulfite [23134-05-6] ate effective against molds, bacteria, and certain strains of yeast. The wine industry represents the largest user of sulfites, because the compounds do not affect the yeast needed for fermentation. Other appHcations include dehydrated fmits and vegetables, fmit juices, symps and concentrates, and fresh shrimp (79). Sulfites ate destmctive to thiamin, and cannot be used in foods, such as certain baked goods, that ate important sources of this vitamin. 

Mud Toxicity Test. Presently, the only toxicity test for drilling fluids having an EPA approval is the Mysid shrimp bioassay. The test was developed in the mid-1970s as a joint effort of the EPA and the oil industry. 

Recently, an enzymatic method was reported to recover the three main components of industrial shrimp waste (protein, chitin, and astaxanthin) using treatments with alcalase and pancreatin. The first enzyme was more efficient in increasing the recovery of protein from 57.5 to 64.6% and of astaxanthin from 4.7 to 5.7 mg/lOO g of dry waste. 

Thus chitin is abunckmt in the sea, in diatom blooms and in the zooplankton, most notably in the shoals of krill and on the land, in invertebrates and in fungi in the soil. Potential industrial sources are wastes from shrimps and crabs, krill, squid, clams and oysters, and fungal fermentations (13). The krUl fishery alone produces 3000 tons per year, currently going to waste. 

Because of the global nature of the industry, uniform standards for seafood freshness are needed. The U.S. imports large quantities of shrimp from other nations. Some of these countries have advanced technology, while others are fairly primitive in operation and troublesome both with quality and health-related matters (2). Thus, quality standards may be difficult to implement on a worldwide basis. 

Shell wastes from shrimp, crab, and lobster processing industries are the traditional source of chitin. However, commercial production of chitosan by deacetylation of crustacean chitin with a strong alkali appears to have limited potential for industrial acceptance because of seasonal and limited supply, difficulties in processing, particularly with the large amount of waste of concentrated alkaline solution causing environmental pollution, and inconsistent physico-chemical properties (Chatterjee et ah, 2005). 

Chitin is a polysaccharide constituted of N -acctylglucosamine, which forms a hard, semitransparent biomaterial found throughout the natural world. Chitin is the main component of the exoskeletons of crabs, lobsters and shrimps. Chitin is also found also in insects (e.g. ants, beetles and butterflies), and cephalopods (e.g. squids and octopuses) and even in fungi. Nevertheless, the industrial source of chitin is mainly crustaceans. 

Shrimp shell waste can be economically converted to chitin, a mucopolysaccharide (Santhosh and Mathew, 2008). This marine polysaccharide and its derivatives hold a major part in our lives as medicines, cosmetics, textiles, paper, food, and other branches of industry because of their unique nature in properties such as low toxicity, biocompatibility, hydrophobicity, etc. Hydrolysis of chitin yields a value added product, glucosamine. Carboxymethylchitin is another derivative of chitin, prepared by the carboxymethylation reaction. 

Van Heerden, J. 2003. Circular with regards to frozen prawns (shrimps). South African Bureau of Standards, Foods and Associated Industries. 

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