Studies On Concentrating And Recovering Engraulis Japonicus Cooking Soup With Membrane Separation Technologies

The features of Engraulis japonicus are small body, easy rotten and low value. Because of the high endogenous enzyme and content of fat, they were extremely apt to rot and must to be processed immediatelyly out of water. With the improvement of the technology in on-board processing, it had formed a"fishing-processing integration"of mobile processing mode to produce dried Engraulis japonicus products. With the annual output of 3,000 tons, there would be 5,250 tons cooking soup every year. At present, the utilization of cooking soup of Engraulis japonicus which was rich in proteins was low and some wre even discarded directly. It not only wasted the resources, but also polluted the marine and terrestrial environments.?It is the inevitable trend to make the wastes into the treasures in the modern seafood high-value processing.Ultrafiltration and Nanofiltration was used for concentrating and recovering protein and amino acid from Engraulis japonicus cooking soup. The effect of desalination was also studied.The mechanism of membrane flux decline was syudied and membrane flux decline process was also simulated. The main contents of this paper as following:Technical route of concentrating and recovering effective ingredients from Engraulis japonicus cooking soup were confirmed as: microfiltration with the pore size of 0.2μm was used for the preprocessed measurement. Then ultrafiltration with the pore size of 30kDa was used for concentrating. The method had the advantages of faster processing speed and better desalination. But the effect of concentrating amino nitrogen was poor. Ornanofiltration was used to concentrate the cooking soup which was pretreated by microfiltration. The method had the advantages of better effect of concentrating proteins and amino nitrogen. But the processing speed was slower and the desalination was poorer. The concentrated soup was reserved for the preparation of anchovy sauce.The method of SDS-PAGE gel electrophoresis was used to study the distribution of protein molecular weight in cooking soup. The results showed that protein molecular weight were greater than 36KDa. Five PES (Polyethersulfone) membranes with different MWCOs were used in the experiment according to the molecular weight distribution of proteins in the soup. The membrane with MWCO of 30kDa was selected as the optimal membrane for further investigations accoding to the membrane flux, retaining ratio of protein, amino nitrogen and NaCl. Orthogonal test was carried out to optimize the process parameters basing on the single test. The optimalizing operating conditions of Ultrafiltration with the pore size of 30 KDa were as following: temperature 30℃,operating pressure 0.30 MPa, flow speed 10.5L/h, sample pH 8.5,membrane flux 146.5 L/m2h.Volmue concentration times after concentrating cooking soup was 6.0, protein concentration times was 5.12, retaining ratio of protein was 85.3%; amino nitrogen concentration times was 1.56, retaining ratio of amino nitrogen was 26.1%; NaCl concentration times was 2.77, retaining ratio of NaCl was 46.1%. It showed good separate performance in concentrating protein and desalination, but the effect of concentrating amino nitrogen was poor. The research will provide helpful references for the high value application of by-products from Engraulis japonicus product processing.The single chemical cleaning agents were used for cleaning the PES membranes. The results showed that washed with distilled water for the firet 30min, 0.3N NaOH for the second 30min and finally washed with distilled water to neutral, the membrane flux recovery can reach to 91.4%. Because of the less use of chemical cleaning agents and easy operate, the cleaning method can be used for industrial mass production in the cleaning of PES membranes.Based on Matlab 7.1.0 Release statistical software and multivariate nonlinear regression method, the mode of concentrating Engraulis japonicus cooking soup with Ultrafiltration was established. The results showed that the deviations of membrane flux were small and ranged between 0.44% to 10.00%. The simulation results agreed with the experimental results well and the correlative coefficients were all around 0.99. So it can basically accurate the membrane flux under different operating conditions. Using this model in industrial design and practice, flux change can be predicted. So we can control the concentration polarization and membrane pollution effectively. Polyamide Nanofiltration membranewas used for concentrating amino acid and protein from Engraulis japonicus cooking soup. The optimalizing operating conditions of Nanofiltration were as following: temperature 30℃, operating pressure 2.0 MPa, sample pH 8.5, flow speed 1.4m3/h. Volmue concentration times after concentrating cooking soup was 5.0, amino nitrogen concentration times was 4.61, retaining ratio of amino nitrogen was 92.2%; protein concentration times was 4.9, retaining ratio of protein was 98.0%; NaCl concentration times was 4.77, retaining ratio of NaCl was 95.4%, membrane flux was 14.93L/m2h1. It showed good separate performance in concentrating amino nitrogen and protein, but the effect of desalination was poor. But it did no affect to the prepararion of anchovy sauce. Meanwhile, the polyamide membrane had the advantage of easy cleaning. Therefore, it was suitable for continuous large-scale industrial process.