Marine Hydrolysates

The previous section has evidenced that NH3-SCR technology has been used successfully for more than two decades, to reduce NOx emissions from power stations fired by coal, oil and gas, from marine vessels and stationary diesel engines. NH3-SCR technology for high-duty diesel (HDD) vehicles has also been developed to the commercialization stage and is already available as an option in the series production of several European truck-manufacturing companies starting from 2001. For mobile source applications, the preferred reductant source is aqueous urea, which rapidly hydrolyses to produce ammonia in the exhaust stream. 

Payne [30] carried out a field investigation of benzopyrene hydrolysate induction as monitor for marine petroleum pollution. Isaaq et al. [31] isolated stable mutagenic ultraviolet photodecomposition products of benzo(a)pyrene by thin-layer chromatography. 

Strickland JDH, Solorzano L (1966) Determination of monoesterase hydrolysable phosphate and phosphomonesterase activity in seawater. Some continued studies in marine science. Springer, Berlin, pp 665-674... 

Iron hydrolysis and solubility revisited Observations and comments on iron hydrolyses characterizations. Marine Chem. 70 23—38 Byrne, R.H. Kester, D.R. (1976) Solubility of hydrous ferric oxide and iron speciation in seawater. Marine Chem. 4 255—274 Byrne, R.H. Luo,Y.-R. (2000) Direct observations of nonintegral hydreno ferric oxide solubility products K Sq = [Fe ][H ] Geo-chim. Cosmochim. Acta 64 1873-1877 Cabrera, F. de Arambarri, P. Madrid, L. ... 

The application of high-sensitivity ICP-MS detectors coupled to HPLC has enabled the detection of trace arsenic compounds present in marine animals. Thus, arsenocholine has been reported as a trace constituent (<0.1% of the total arsenic) in fish, molluscs, and crustaceans (37) and was found to be present in appreciable quantities (up to 15%) in some tissues of a marine turtle (110). Earlier reports (46,47) of appreciable concentrations of arsenocholine in some marine animals appear to have been in error (32). Phosphatidylarsenocholine 45 was identified as a trace constituent of lobster digestive gland following hydrolysis of the lipids and detection of GPAC in the hydrolysate by HPLC/ICP-MS analysis (70). It might result from the substitution of choline with arsenocholine in enzyme systems for the biogenesis of phosphatidylcholine (111). 

FIGURE 4.5 p-Secretase-inhibitory activity of various enzymatic hydrolysates from marine zooplankton, rotifer (Byun et ai, 2009a). 

As antioxidant peptides are rarely present in marine invertebrates, they must be released from the parent protein by hydrolysis with enzymes. Various enzymes have been used to release peptides from muscle proteins. To date, different muscle proteins have been extracted, hydrolysed, and their antioxidant activities studied, which is among all invertebrate muscles the most similar to vertebrate skeletal muscle. Various studies have been conducted to investigate the antioxidant properties of hydrolysates or bioactive peptides from marine invertebrate sources like oysters... 

In another study conducted on marine zooplankton (Byun et ah, 2009b), antioxidant activity was measured for the DPPH radical of hydrolysates produced by Alcalase, a-chymotrypsin, Neutrase, papain, pepsin, and trypsin. To identify antioxidant peptides, peptic hydrolysate was purified using consecutive chromatographic methods, and antioxidant peptides were identified to be Leu-Leu-Gly-Pro-Gly-Leu-Thr-Asn-His-Ala (MW 1076Da) and Asp-Leu-Gly-Leu-Gly-Leu-Pro-Gly-Ala-His (MW 1033Da) by Q-TOF ESI mass spectroscopy. IC50 values of purified peptides were... 

This suggests that products with bioactive peptides derived from marine invertebrates can meet the needs of marine organism-derived products due to health and/or religious reasons. From such a viewpoint, hydrolysates or bioactive peptides from marine invertebrates can be interesting sources of bioactivity peptides in the treatment of chronic diseases. 

According to Lee et al. (2010), the peptide Gly-Asp-Leu-Gly-Lys-Thr-Thr-Thr-Val-Ser-Asn-Trp-Ser-Pro-Pro-Lys-Try-Lys-Asp-Thr-Pro, derived from big-eye tuna frame protein hydrolysate, showed a strong suppressive effect on the systolic blood pressure of SHRs, while its antihypertensive activity was similar to that of captopril, a commercially available antihypertensive drug. Further, they reported no side effects after the administration of this antihypertensive peptide to rats. In addition, these marine antihypertensive peptides exhibit stronger antihypertensive activity in vivo than in vitro. The exact mechanisms underlying this phenomenon have yet to be identified however, it was suggested that bioactive peptides have a higher tissue affinity and are eliminated more slowly than captopril (Fujita and Yoshikawa, 1999). 

Lee, T. G. (1996). Functional peptides from hydrolysate of marine oyster proteins. Ph.D. thesis, Pukyong National University, Korea. 

Sampath, K. N. S., Nazeer, R. A., and Jaiganesh, R. (2011). Purification and identification of antioxidant peptides from the skin protein hydrolysate of two marine fishes, horse mackerel (Magalaspis cordyla) and croaker (Otolithes ruber). Amino Acids, doi 10.1007/ s00726-011-0858-6. 

Discarded fish bones and cutoffs may contain considerable amounts of muscle proteins. These muscle proteins are nutritionally valuable and easily digestible with well-balanced amino acid composition (Venugopal et al., 1996). Therefore, fish proteins derived from seafood processing by-products can be hydrolyzed enzymatically to recover protein. Protein hydrolysates from several marine species have been analyzed for their nutritional and functional properties, and researches have mainly explored the possibility of obtaining biologically active peptides (Benkajul and Morrissey, 1997). Moreover, skipjack tuna muscle (Kohama et al., 1988), sardine muscle (Bougatef et al., 2008), and shark meat (Wu et al., 2008) have been used to separate potential peptides. 

He, H. L., Chen, X. L., Sun, C. Y., Zhang, Y. Z., and Zhou, . C. (2007). High throughput and rapid screening of marine protein hydrolysates enriched in peptides with angiotensin-I-converting enzyme inhibitory activity by capillary electrophoresis. Bioresour. Technol. 98, 3499-3505. 

Fish, other marine animals, their products and by-products fish, fish oil and cod-liver oil not refined fish molluscan or crustacean autolysates, hydrolysate and proteolysates obtained by an enzyme action, whether or not in soluble form, solely provided to young animals. Fishmeal... 

Compiano, A.M., Romano, J.C., Garabetian, F., Laborde, P., and Giraudiere, I. (1993) Monosaccharide composition of particulate hydrolysable sugar fraction in surface microlayers from brackish and marine waters. Mar. Chem. 42, 237-251. 

Enzymatic Production of Marine-derived Protein Hydrolysates and Their Bioactive Peptides for Use in Foods and Nutraceuticals... 

Enzymatic production of marine-derived protein hydrolysates 492... 

Enzymatic hydrolysis has long been used to produce functional protein hydrolysates from vegetable and milk proteins however it also shows great potential for use in marine products. During the 1960s and 70s, initial research began into the utilization of fishery by-products through the production of marine-... 

MARINE-DERIVED PROTEIN HYDROLYSATES AND THEIR BIOACTIVE PEPTIDES... 

Food materials, including fish, contain the precursors to these bioactive peptides, which can be formed in vitro or in vivo by enzymatic hydrolysis (Korhonen and Pihlanto 2003). During the past decade, a number of studies have reported on the many physiological properties of these bioactive peptides. The aim of this review is to describe the production of novel peptides derived from marine protein hydrolysates, elucidating the underlying mechanisms of physiological and biofunctional activity that are particular to individual bioactive peptides. The general sources and production of protein hydrolysates will be discussed, followed by a discussion of the nutraceutical properties of protein hydrolysates and their associated bioactive peptides. 

ENZYMATIC PRODUCTION OF MARINE-DERIVED PROTEIN HYDROLYSATES... 

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