Shrimp enzymes

Radiation-Induced Changes in Shrimp Enzymes Involved in Spoilage... 

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. 

Horst, M.N. 1981. The biosynthesis of crustacean chitin by a microsomal enzyme from larval brine shrimp. Jour. Biol. Chem. 256 1412-1419. 

Endogenous chitinases are already fortuitously used in food processing in the de-shelling of shrimps, which is accomplished after a period of storage during which time the dead shnmp s enzymes loosen the chitinous attachments between meat and shell. 

The remainder of tMs paper will provide evidence that impedance can be used to detect shrimp freshness. The theory for this study is simply that increasing spoilage, whether due to microorganisms or inherent enzymes, should increase the concentration of charged metabolic products that should be measured using readily available conductance or impedance equipment. 

Shrimp samples held at 5°C showed increasing I-values during storage compared to frozen samples presumably due to increased breakdown of muscle tissue by inherent enzymes and/or increased microbial action. 

Cheung, I. W. Y. and Li-Chan, E. C. Y. (2010). Angiotensin-I-converting enzyme inhibitory activity and bitterness of enzymatically-produced hydrolysates of shrimp (Pandalopsis dispar) processing byproducts investigated by Taguchi design. Food Chem. 122,1003-1012. 

He, H. L., Chen, X. L., Sun, S. Y., Zhang, Y. Z., and Zhou, . C. (2006). Analysis of novel angiotensin-I-converting enzyme inhibitory peptides from protease-hydrolyzed marine shrimp Acetes chinensis. ]. Pept. Sci. 12, 726-733. 

Wong, A. H. K. and Mine, Y. (2004). Novel fibrinolytic enzyme in fermented shrimp paste, a traditional Asian fermented seasoning. J. Agric. Food Chem. 52, 980-986. 

Figure B3.1.2 Native discontinuous polyacrylamide gels activity stained for proteinases. (A) Gel stained with Coomassie brilliant blue for total protein. (B) Gel assayed for proteinase activity using casein as a substrate. Samples are enzyme extracts of hepatopancreas from four shrimp species. Lane 1, molecular weight markers Lane 2, Rcaliforniensis Lane 3 R vannamei Lane 4, Rpaulensis, Lane 5, P. schmitti.

Tsukada (30) have examined developmental changes of the enzyme in chick brain and spinal cord. Enzymic activity appears at about the eighteenth day of incubation and increases rapidly until 3 days after hatching in the brain and between 18 and 21 days of incubation in the spinal cord. These are precisely the periods of active myelination in the brain and spinal cord of the chick, respectively. Similarly, brain tissue of the newborn rat is devoid of cyclic phosphate diesterase activity it appears at about 8 days after birth and increases dramatically between the tenth and thirty-fifth day of life (29). This coincides precisely with the development of myelin in this species. The diesterase is essentially absent in the brain of the jimpy mouse (31), a lethal mutant devoid of myelin in the central nervous system. It is also absent from the spinal cord of this mutant. The enzyme is about 50% deficient in brain tissue of the quaking mouse (29), a mutant with partial deficiency of myelin. There is no activity in nerve fibers and ganglia from a variety of invertebrates such as squid, octopus, crab, shrimp, and starfish. Nerve tissue in these organisms is nonmyelinated. All these observations point to an intimate association of the enzyme with myelin in vivo. 

Irradiation of commercial shrimp in which melanogenesis had begun accelerated the reaction. It was postulated that the quinone-like end products of the reaction sequence acted as competitive inhibitors for the reaction and also functioned as radiation protectors for the enzyme. Subsequent irradiation would destroy the capacity of the end products to inhibit the reaction and simultaneously preserve the enzyme activity, thus accelerating further melanogenesis. 

Trehalose, a disaccharide sweetener, 45-50 percent as sweet as sucrose, was given GRAS status in 2000. It is naturally found in mushrooms, honey, lobster, shrimp, and foods made with yeast. It has been used in Japan for decades, and is commercially produced from starch by bacterial enzymes.98 Besides its mild sweetening power, it maintains cell structure during freezing and dehydration of foods. It is a nonreducing sugar, so it does not participate in the Maillard reaction (will not brown) and helps to protect the color of processed foods.99... 

Chitin is a protein complex found in shellfish shells. When shells of lobsters, crabs, shrimp, and other shellfish are added to the soil, the chitin stimulates population growth of beneficial soil microorganisms. These microorganisms produce the enzyme chitinase, which destroys nematode eggs and larvae. As chitin breaks down, nitrogen and potassium become available to plants. 

Hexopar inositol nicotinate nicotinic acid, hexoprenaline [ban, inn] (hexoprenaline hydrochloride [jan]) is a P-ADRENOCEPTOR agonist selective for the P2-subtype that therapeutically can be used as a BRONCHODIIATOR in ANTIASTHMATIC treatment, hexoprenaline hydrochloride hexoprenaline. hexuronic acid ascorbic acid, hexylcaine [inn] (hexylcaine hydrochloride [usan]) is an ester series LOCAL ANAESTHETIC, used by topical application for the local relief of pain, hexylcaine hydrochloride hexylcaine. hexylresorcinol [usan] is a urinary ANTISEPTIC and an ANTHELMINTIC. It inhibits melanosis (blackspot) in shrimps, and is used as a food additive for prevention of enzymic browning in shrimps and fruits, hexyltheobromine pentifylline. 

Shrimp alkaline phosphatase (SAP) (United States Biochemical, Cleveland, OH). This enzyme is preferred to calf intestinal phosphatase (CIP) because it is heat-labile in its 10X reaction buffer 200 mM Tris-HCl, pH 8.0,100 mMMgCl2. 

---