| China has the largest kelp farming and production in the world, and the annual output of kelp was 1.2 million tons. Kelp contains a large amount of fucoidan, iodine, mannitol. Fucoidan has been extensively studied due to its numerous biological activities, including antioxidation, anti-virus and anti-cancer, which have revealed that fucoidan has broad application prospects in functional foods, health products, maquillage and pharmaceuticals industries. However, the fucoidan industrialization was immaturate, and maimly processing method was dry kelp immersion, which result in the low resource utilization ratio of fucoidan in kelp. Further development of fucoidan in kelp, and enhance the yield and utilization value of fucoidan were important to promote the processing technology and value of kelp.In this study, the content of fucoidan, iodine and mannitol in four species fresh kelp firstly. Then the composition and antioxidant activity of fucoidans obtained from these kelps were compared. And effects of different processing on the fucoidan from the product and byproduct. Moreover, we optimizied the process of extracting iodine and initial explorated the fucoidan concentration to improve the development and use of the kelp blaching water.The main results are as follows.1. Sulfuric acid- phenol method was a common and effective method for the determination of polysaccharide. Experiments showed that the method had high accuracy and good reproducibility, and was suitable for the detection of fucoidan analysis.2. The optimum experimental conditions were determined by orthogonal experiment: soaking temperature 60 oC, soaking time 3 h, ratio of buffer: alga 20.0 m L/g, the ratio of contraction was 4.11 mg/m L. It was shown that all the highest contents were in the last picking time. The highest content of fucoidan was in Xinbenniu, the dry weight ratio reached 0.69%; the highest content of manntiol was in Haikeyihao, the dry weight ratio reached 12.88%; the highest content of iodine was in Zaoshu, the dry weight ratio reached 0.45%.3. The composition and antioxidant activity of fucoidans, which were obtained from different species kelp in the same period by the method of pressing and alcohol precipitation, were studied. Results showed that samples were mainly composed of fucoidan(39% ~ 51%) and sulfate content(26% ~ 37%), and fucose was the main component of fucoidan. Results of antioxidant activity showed that, at a concentration of 2.0 mg/mL, the highest DPPH free radical scavenging ratio was IN FSH, which was reached 63.97%; the highest hydroxyl free radical scavenging ability and reducing power were both in FHK1 H, which were 54.90% and 0.475 respectively.4. Blanching, squeezing and air-cure processings were simulated, and fucoidans were extracted from the byporducts and products. Composition, functional properties and antioxidant properties were investigated. Results showed that, Fsq had the highest content of fucoidan and sulfate, which were reached 43.93% and 35.66% respectively, the highest stacking density, solubility, oil absorption capacity and emusifying activity and the most antioxidant activity. At the concentration of 2.0 mg/mL, the DPPH free radical scavenging ratio was 63.97%; the hydroxyl free radical scavenging ratio was 54.90% and reducing power was 0.475.Fucoidans were extracted from the byproducts and products of fresh Laminaria japonica production processes. All extracts were shown to exhibit characteristics of fucoidan by FTIR, and measurements of composition, including fucoidan, fucose, and sulfate. All crude fucoidans contained v A.R.iety fucose and sulfate group. The results showed that the highest content of fucoidin was Fai(43.93%), the highest sulfate content was in Fsq(40.92%). The results showed that the most active functional properties and antioxidant properties was Fsq. At a concentration of 2.0 mg/mL, the DPPH free radical scavenging ratio was 63.97%; the hydroxyl free radical scavenging ratio was 54.90% and reducing power was 0.475.5. The air blow-out method was utilized to exact iodine from kelp blanching waste water and the experimental conditions, such as the pH, temperature and the air flow, were optimized by the orthogonal experiment. In addition, the effect of different oxidizers(H2O2, NaClO, NaNO2) under the optimized condition were tested. The results showed that the optimum reaction condition was pH 2.0, temperature 80 ℃ and the air blown 3 L/min, the exaction rate was up to 96.2%. There is no significant difference on the oxidizing effect among three oxidizers. The results of bleaching water ultrafiltration concentration experiment show that the concentration of fucoidan was increased from 0.3 mg/m L to the 6.59 mg/m L by the 8000 molecular membrane, nearly 32 times. |
PDF Full Text Request