Extraction Process Optimization By Ultrasonic Assisted Complex Enzymes And Modification For Citrus Pectin

Pectin is an important polysaccharide for the component of cell walls. Because it has good effects of thickening, anti-cancer, anti diarrhea, pectin is widely used in food, pharmaceutical and other industries as thickeners, emulsifiers, suspending agents, sustained-release agents. Stage method for the extraction of pectin drawbacks, a process optimization and a phosphorylated modification were studied based on pectin extraction process, and the follows were main research contents and results.Ultrasonic-assisted for compound enzymes extraction of citrus peel pectin process were optimized. The effects of different pretreatment methods on the yield of pectin were analyzed. On the basis of single factor experiment, the optimum conditions that the solid-liquid ratio1:20(g/ml), ultrasonic power187.5W, ultrasonic time65.3min, enzyme dosage5.6mg, pH4.82and temperature41.8℃were gotten by Box-Behnken Design Response Surface method. Under this condition, the actual yield of pectin was11.93%which illustrated that the yield of pectin was greatly improved by this optimization process, the model could predict the yield of pectin and compared with pure enzyme treatment, the processing time was reduced4-5h.On the basis of the single factor, a phosphorylated modification of pectin was researched by Box-Behnken Design with phosphate content of the product as the response value, the variable of composite phosphoric reagent concentration, temperature, time and pH. Through experiments and analysis, the effects of phosphate content on phosphorylation of pectin’s primary and secondary factors were reaction temperature> phosphorylation reagent concentration> reaction time> pH; The model at the level of93.1%can fit the experimental data, there was about2%errors between theoretical and actual values by the practical verification and was able to interpret the relationships of content of phosphate products and reaction conditions. The optimal preparation conditions is the phosphorylation reagent concentration0.11g/ml, the reaction temperature78.1℃, reaction time4.24h, pH8.06. Therefore, the preparation conditions by the Box-Behnken Design was true and reliable.The physical and chemical properties of modified pectin such as water dispersibility, thermal stability, water retention, pH, hardness were changed, while leading to changes in the scope of application of pectin. It is not only opened up the diversification of pectin varieties, but also could provide a theoretical basis for the application of pectin in functional foods and medicines.