Preparation And Function Evaluation Of Enzymatic Hydrolysates Of Marine Proteins Enriched Oligopeptides

The creature in the sea have formed special structure and function to adapt the special environment in the sea ,such as high pressure, low nutrition, high salt, low temperature especially in deep sea, high temperature near the volcano mouth in the deep sea bed. The marine creature provides man a lot of bioactive material with new structure and special function, including terpene, sierols, glucoside, polysaccharide,peptides, nuclear acids, proteins and enzymes. Marine proteins have wide source and abundant content, which have potential in gene engineering medicine. Therefore, marine proteins are becoming a research hot spot of marine bioactive materials. Now, beside as man food, most of the marine proteins with low value and the leftover bits and pieces of marine product processing become fish powder through pressing and drying or were .abandoned. Their adding value is very low. High-value utilization of the low value marine proteins is now an urgent research content of marine bio-technology. Ferment engineering and enzyme engineering technology are important path for the development of utilization of marine proteins. The peptides formed by protein hydrolysis by proteases have advantages of low molecular weight, good emulsification, enhancement of hot-adapted ability, easy absorbance by organism and new bioactivity and was used in many field.In this article, four kind of marine proteins— taking shark, oyster, scallop, shrimp were hydrolyzed whit 4 kind of protein enzymes—protease of SM98011, Alcalase, protease of SM97010 and Flavourzyme. Four protein hydrolysates were obtained. the content of protein, amino acids and peptides in every hydrolysate were tested. The content of amino acids in all hydrolysates were markeredly high and balanced. The content of essential amino acids in all hydrolysates were especially high and their ratio was obvious higher than that of WHO/FAO standard (35.38%). So, the hydrolysates of 4 marine proteins were all protein resource with high nutrient value. They could be used as high quality forage additive, even alternatives of dairy products. The ratio of essential amino acids in the hydrolysate of taking shark hydrolyzed whit Flavourzyme is the highest (48%).Besides the high concent of essential amino acids in the hydrolysates, the content of flavor amino acids, such as Glu, Asu and Gly, in the hydrolysates is also abundant. The contents of flavor amino acids in the hydrolysates from protease of SM98011 and Flavourzyme were obviously higher than that in the hydrolysates from the other two proteases. This result indicated that protease of SM98011 and Flavourzyme were good enzymes used to digest marine protein resource to develop seafood flavouring.The peptide ratio in the hydrolysates from protease of SM98011, Alcalase andprotease of SM97010 were obviously higher than the control, especially in the oyster hydrolysate and scallop hydrolysate from these three proteases. This result showed that these three proteases contained a lot of endopeptidases and they could be used to screen active peptides.Through the animal model of trans planted tumor in mice, the anti-tumor activity of the hydrolysates and the effect of the hydrolysates on lumph apparatus were studied. The hydrolysates of oyster and scallop not only had a high inhibition rate, but also could activate thymus function. The hydrolysate of shark digested by Protamax had the lowest inhibition rate and no effect on lumph apparatus.The antioxidant activities of the hydrolysates of 4 marine proteins digested by 4 proteases were studied in this article. The result showed that the hydrolysates from protease of SM98011 and protease of SM97010 had higher antioxidant activities than the other two protease hydrolysates.