Study On Nutritional Components And Properties Of Crude Polysaccharides From Bottom Farmed Sea Cucumbers In Different Origins Of Dalian

Sea cucumber has high economic value,and it not only is rich in nutrients and but also contains a variety of bioactive ingredients.Sea cumcumber is a good source of healthy,green and nutritious food.The contents of main nutrient components and crude polysaccharides in sea cucumbers vary in different origins due to different growth environments.In this paper,bottom farmed sea cucumbers from 8 origins of Dalian were adopted as raw materials.The main nutritional components were analyzed and compared.The extraction process of crude polysaccharides from sea cucumber was optimized by response surface methodology.The structure,monosaccharide composition and thermal properties of crude polysaccharides were studied.The antioxidant activity was analyzed and compared,and the main results were as follows:1.The main nutritional components(protein,ash,fat,carbohydrate,amino acid,collagen,taurine,saponin and polysaccharide)of bottom farmed sea cucumber from 8 rigins of Dalian were compared and analyzed.The bottom farmed sea cucumbers from different origins had remarkable differences in main nutritional components.protein contents were in the range of 41.2~48.3g/100 g,ash 24.0~29.7g/100 g,fat 2.3-5.2 g/100 g,carbohydrate 13.5~20.9 g/100 g,total amino acid 31.5~43.8%,collagen 111.2~210.2 mg/g,taurine 6.8~12.0 mg/g,saponin 1.15~1.81 g/100 g and polysaccharide 8.1~13.8 g/100 g,respectively.2.The response surface method was used to optimize the extraction process of sea cucumber polysaccharide.The best enzyme was neutral protease,and the optimal conditions were as follows: amount of enzyme added 1.5%,pH 7.0 and temperature 55℃.Polysaccharide compositions were analyzed by chemical method,and the results showed that amino sugar contents were in the range of 6.1~10.8 g/100 g,fucose 3.3~4.9 g/100 g,uronic acid 4.9~9.1 g/100 g,and sulfate group 0.2~0.4 g/100 g.There were significant differences among the sea cucumber polysaccharide compositionsin 8 origins.The sea cucumber polysaccharide monosaccharides were analyzed by high performance liquid chromatography,and the results showed that 7 monosaccharides were detected in polysaccharides from 8 origins.Contents of mannose,glucosamine,glucuronic acid,galacturonic acid,glucose,galactose and fucose were fluctuated within the range of 0.07~1.40g/100 g,0.23~1.64g/100 g,0.08~0.57g/100 g,0.08~0.44g/100 g,0.05~2.24g/100 g,0.07~0.93g/100 g and 0.20~6.42g/100 g,respectively.The contents of monosaccharides in sea cucumber polysaccharides in 8 origins was significantly different.The absorption peaks of characteristic groups of fucose methyl,acetamido,carboxylic acid and sulfate groups were detected by infrared spectroscopy.3.Thermal properties of dried powders and crude polysaccharides from 8 origins sea cucmber were studied,and the results showed that thermal properties were different both among dried powders and crude polysaccharides from 8 origins.Peak temperature and enthalpy varied in polysaccharides from 8 origins,and numbers of exothermic and endothermal peaks in some origins were different.However,DSC profiles among both dried powders and crude polysaccharides were similar.4.Antioxidant activities of sea cucumber polysaccharides from 8 origins were tested,and the results showed that sea cucumber polysaccharides had strong antioxidant capacity.Within the concentration of 1.75 mg/ml,DPPH free radicals and ABTS free radicals scavenging rates increased linearly,and DPPH free radicals and ABTS free radicals scavenging rates showed slow increase with the increase of concentrtion;Iron reduction capacity,superoxide anion radical scavenging rate and hydroxyl radical scavenging rate showed a linear increase.