| With the rapid development of economy and technology, the living standards of people is increasing day by day, people put forward higher requirements for vegetable oil quality. meanwhile it also puts forward higher requirements to produce the health, nutrition, safety, good storage stability and the inexpensive vegetable oil on China's oil refining processing industry, to meet consumers for the urgent request of vegetable oil quality. Degumming is the basis of oil refining processing, traditional degumming process effect is poorer, the environmental pollution is larger, and the enzymatic degumming with its best degumming effect and the advantages of less environmental pollution pay more and more attention. The research discussed the process of enzymatic degumming combined with the traditional hydration degumming pretreatment, and response factors which influence the phospholipase Lecitase Ultra degumming were discussed. The main research content is as follows:(1) After analysis of the single factor, the optimal operation conditions for hydrated degumming are as follows: water content, reaction time, hydration temperature, and stirring speed, was, 8%, 30 min, 75 and 300 r/min, respectively. The content of residual phosphorus ?after hydration degumming was 102.6±1.1 mg/kg. Enzymatic degumming after hydration degumming not only save the dosage of enzyme, but also can shorten the reaction time of enzymatic degumming at the same time.(2) In order to increase the degumming rate of soybean oil, traditional method to improve the degumming effect was compared and modified by the method of magnetic water assisted phospholipase Lecitase Ultra. Based on the single factor design, the Plackett-Burman experimental design was used to screen and optimize the significant ones on the degumming rate, the further parameters were analyzed by the Box-Benhnken experimental design with this magnic water assisted phospholipase method on the degumming technology. The results of optimal parameters indicated that the magnetic water content, dosage of enzyme, reaction time, temperature, and pH, was 3%, 34 mg/kg, 3.2 h, 46 ?and 4.8, respectively, in which the degumming rate of soybean oil was 95.03%, and that of rate was improved to 4.54% in comparison with the traditional method of water assisted phospholipase Lecitase Ultra. The improved method of the magnetic water assisted phospholipase Lecitase Ultra can decrease the colloid compound in soybean oil significantly.(3) Soybean oil used phospholipase Lecitase Ultra with ultrasound assisted was degumming. The catalytic reaction rate of phospholipase Lecitase Ultra was accelerated, the optimum reaction temperature was increased,the optimum water dosage was reduced,but the optimal pH of phospholipase Lecitase Ultra was not altered in ultrasound field.Compare to the quality of oil under different treatment methods, most of the metal ions were separated by enzymatic method, metal ion content was significantly reduced in the oil. Phospholipase Lecitase Ultra did not significantly increase the content of fatty acid in ultrasound field, but the Oxidative stability index(OSI value) of the oil was reduced, which can make oil easy to oxidize.(4) The effect of metal ions, nonionic surfactant and acid treatment on the phospholipase Lecitase Ultra was studied.The catalytic reaction of phospholipase Lecitase Ultra can be influenced by the metal ions in soybean oil. Ca2+ and Mg2+ played positive effect; Fe3+ and Cu2+ played negative effect. Zn2+ showed a promotion effect at lower concentration, and the Zn2+ was inhibited at higher concentration. For the study of nonionic surfactants, the degumming rate of adding magnetized water experimental group was significantly higher than deionized water experimental group. The degumming rate of Tween 20 and Span 40 experimental group were higher than magnetized water experimental group, but the difference was not significant(P < 0.05). The degumming rate of Tween 80 and Span 80 experimental group were higher than the other experimental group,and the degumming rate of Tween 80 reached the highest value 96.74±0.47%. The result of different acid pretreatments, the optimum reaction pH of phospholipase Lecitase Ultra was citric acid,and the result was significantly better than other acids, which can also chelate metal ions at the same time. |
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