Study On Isolation And Activity Of Polysaccharides From The Ink Of The Sthenoteuthis Oualaniensis In South China Sea

Sthenoteuthis oualaniensis is a kind of resources that being potential, which widely distribute the tropical and subtropical Indo-Pacific oceans, of which the South China Sea quantity is larger.Rich in a variety of active substances in the squid ink, the main active ingredient is melanin and protein polysaccharide complexes, which has many physiological function, anti-aging, antioxidation, anti-cancer, enhancing immune ability and so on. With its source widespread and non-toxic, Polysaccharide has many physiological function, anti-tumor, anti-virus, antioxidation, immunoregulation, hypoglycemic ability and so on. There were many studies on animal Polysaccharides of natural resourees recently, but there were few reports on the polysaccharides from the ink of the Sthenoteuthis oualaniensis in South China Sea. This paper focused on the nutritional component analysis, extraction, purification, and antibacterial, antioxidant, fresh keeping activity of polysaccharides from the ink of the Sthenoteuthis oualaniensis in South China Sea.1. The composition and content of the basic nutrients and amino acids, fatty acids and some trace elements and vitamins of Sthenoteuthis oualaniensis ink were analyzed with an atom absorptiometry, gas and liquid phase chromatography as well as general chemical methods. The results shows that the content of water, crude protein, fat and ash in the ink of S.oualaniensis in south China sea are 65%, 30.6%, 0.7%, 2.08%, respectively. Among the 16 kinds of amino acids found, it contains 8 kinds of essential and 1 kinds of half-essential amino acids. Essential Amino acid is about 37.2% of total amino acid in the ink of S.oualaniensis in South China Sea as well as 33.2% of umami amino acid. It contains13 kinds of fatty acids and the unsaturated fatty acid(UFA) is 64%. It is also rich in vitamins and mineral elements such as,K、Na、Ca、Mg、Fe、VB1、VB2、VE, which has significant effect to the operation of the normal physiology function in human body.2.To explore the optimum extraction process of polysaccharide from the ink of the Sthenoteuthis oualaniensis in South China Sea, response surface methodology(RSM) was employed to optimize extraction process of polysaccharide from the ink of the Sthenoteuthis oualaniensis..Along with the center combination experiment design principle, three factors and three levels of response surface analysis was adopted to obtain a multiple quadratic linear regression equation and analyze the interaction among factors chosen Y(polysaccharide content ×total sugar quality)as the response value. The results show that The optimum extraction conditions of polysaccharide from the ink of the Sthenoteuthis oualaniensis in South China Sea were obtained through water extraction and ethanol precipitation, which conditions was ratio of solid to liquid1:2, water extract pH5.5, enzyme concentration1.00%,1/4 volume chloroform-n-butanol(volume 4:1) two steps to remove impurity proteins, the absolute ethanol recipitation to get crude polysaccharide. Under the optimum conditions, the crude polysaccharide yield reached up to 0.91%, the polysaccharide content was 9.8%.3. To analyze polysaccharide components and monosaccharide composition of the ink polysaccharide from the Sthenoteuthis oualaniensis, the polysaccharide was in turn by DEAE- 52 ion exchange column, HR- 300 gel column purification, collecting the eluent, resulting that three different sugar peak :SIP1, SIP2, SIP3 were get. The PMP- derivative method was employed to detect monosaccharide composition of SIP1, SIP2, SIP3, The results show that SIP1 was composed of by D-mannose, D-glucose, D-galactose three monosaccharides according to certain proportion condensation, in the meantime, SIP2 and SIP3 was composed of by D-mannose, Rha, D-glucose, D-galactose and L-fucose five monosaccharides in accordance with the different proportion respectively.4. To study the antibacterial, antioxidant, fresh keeping activity of SIP1 from the ink of the Sthenoteuthis oualaniensis in South China Sea, added the SIP1 to the E. coli bacteria suspension and to determine the absorbance values of OD630 nm.The results show that SIP1 has certain antibacterial activity for e. coli,with the increase of concentration SIP1, in a certain concentration range, bacteriostatic effect and a certain effect relation with the concentration of the sample, when SIP1 concentration reaches 10 mg/m L, almost completely inhibit the growth of e. coli. Methods in vitro antioxidant was employed to determine the removal ability to DPPH free radical, hydroxyl radical and superoxide anion free radical of SIP1, in a certain concentration range, DPPH free radical, hydroxyl radical and superoxide anion free radical removal ability and SIP1 with dose dependent effect, with the increase of SIP1 concentration, scavenging ability increased. The IC50 of scavenging ability to DPPH ·is about 8.45(mg/mL) of SIP1 and hydroxyl free radical is about 6.5(mg/m L).Added different concentration of SIP1 to fresh tilapia fillets soaking liquid and to determine the total number of bacteria in fish, The results show that Soaking by adding SIP1 solution of tilapia fillets experimental group showed good antibacterial effect, and with the increase of the SIP1 concentration, the bacteriostatic effect is enhanced. In conclusion, SIP1 showed good effect on antibacterial, antioxidant, and fresh keeping.