1 Introduction Introduction 2 onions The nutritional content of onion 2 The health onion 2 juice vegetable juice clarification method 3 Enzyme treatment 3 deal with ultrafiltration membrane 4 to clarify the 5-treated to clarify the preservation methods of onion juice 5 Preservation potassium sorbate 5 Preservation of citric acid 5 Prospect of 6 2 Materials and Methods 6 Test materials, equipment and reagents 6 Test Materials 6 Test apparatus 6 Test Kit 7 Test Method 7 Preparation of onion juice 7 onion juice clarification 7 to clarify the clarification of onion juice preservation 7 3 Results and Analysis 7 onion juice pectinase treatment to determine the optimal dosage of 7 onion juice pectinase processing time to determine the optimum water bath 8 pectinase treatment of onion juice to determine the optimum water temperature of 9 Orthogonal analysis of onion juice pectinase to clarify the role of the optimal conditions for 10 to clarify the preservation of onion juice test 11 to clarify the degree of cold storage on the impact of 11 to clarify the degree of citric acid on the impact of 12 Potassium Sorbate onion juice during the period of preservation to clarify the impact of 14 degrees Potassium sorbate and citric acid to clarify the impact of the degree of contrast 15 4 Conclusion ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 16 5 References ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...... 16 6 a vote of thanks ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .............. 18