Control And Removal Of 3-monochloro-1,2-propanediol Esters And Glycidyl Esters In Edible Vegetable Oil

3-Monochloro-1,2-propanediol esters and glycidyl esters are a type of harmful components mainly produced in the deodorization process of oil refining,which has potential harm for human body.It has become a hot issue in food safety research in recent years.Current research indicates that chloride ion is an important precursor for the formation of 3-MCPD esters and GEs.At present,there have been studies on chloride ions in oils,but there is no deeper research on the chloride ions in processing aids used in oil and fat processing Therefore,this paper studied the effect of processing aids on the chloride ion content in oils during the oil refining process,and the effect of changes in chloride ion content on the formation of 3-MCPD esters and GEs in oils.Furthermore,the process conditions of refining and water washing with the greatest possibility of introducing chloride ions in the oil refining process were optimized to prevent and reduce the chloride ion from entering the oil.Corn crude oil was refined under optimized conditions based on the control and removal of chloride ions,and the control effect of chloride removal on the production of 3-MCPD esters and GEs during oil refining was studied.Finally,the process conditions optimization and removal effects of 3-MCPD ester and GEs in oils by molecular distillation were studied.(a)Collected common processing aids used in actual production from different oil and fat processing plants to detect their chloride ion content.Studied the level of chloride ions in processing aids and the possibility and extent of migration into oil during oil refining.The results showed that the chloride ion content in phosphoric acid from different sources(for degumming)was not detected-22.647 mg/kg.The content of chloride ion in alkali(for alkali refining)was not detected-27.009 mg/kg.The difference in chloride ion in phosphoric acid and caustic soda caused a significant difference in the chloride ion content in the refined oil(p<0.05).The chloride ion content in the soft water samples of the three oil plants was 0.746-1091.205 mg/kg,which was a huge difference.The refining tests of soft water(degumming,alkali refining,water washing,bleaching,deodorization)of 3 oil plants showed,the processes of degumming,alkali refining,and bleaching can reduce the chloride ion content of oils to varying degrees(except for oils refined with high chloride ion content water).The water washing process was the most obvious stage for the migration of chloride ions into the oils in soft water.The chloride ion content in the washing oil was linearly related to the chloride ion content in the soft water used for refining,with a correlation coefficient of 0.9962.The test results of 3-MCPD esters and GEs in oils and fats showed that refining with soft water with high chloride ion content will produce 3-MCPD esters before deodorization,with a content of 0.364-0.666 mg/kg.The content of 3-MCPD ester in the oil after deodorization was positively correlated with the chloride ion content of the soft water used for refining,with a linear correlation coefficient of 0.9999.In addition,the laboratory simulated the process of evaporating and stripping the mixed oil in the factory after the brine layer settles.It was found that the content of chloride ions,3-MCPD esters and GEs increased after evaporation of the mixed oil compared with that before evaporation.This may be one of the reasons that chloride ions,3-MCPD esters and GEs can still be detected in unrefined crude oil.(b)In order to further clarify the effect of the oil and refining and washing process on the content of chloride ions in the deacidified oil in refining.Optimized the water washing process conditions,analyzed and studied the effect of the washing process on preventing and eliminating the chloride ion content in the deacidified oil in refining.Based on the effect of the optimized washing conditions on the removal of chloride ions from oils,the optimized washing conditions were applied to the refining process of corn crude oil to study the control effect of the removal of chloride ions on the production of 3-MCPD esters and GEs during the oil refining process.the result shows: Under the best conditions of washed with ultrapure water,added water at 30% oil weight,and washed 3 times,the chloride ion removal rate in alkaline refining after washing can reach 98.12%.Refined corn crude oil with optimized conditions based on control and removal of chloride ions(optimized conditions for water washing process,ultrapure water used for degumming,refining,and deodorization),and the general refining process used in oil factories as a control(15% oil weight was added in water washing process,washed twice,and water with a chloride ion content of 100 mg/kg for degumming,refining,water washing,and deodorization).The results showed that the optimization of the water washing process can reduce the formation of 3-MCPD esters and GEs in the oil washing process(reduced from 0.469 and 0.485 mg/kg to undetected,respectively).The two groups of oils were deodorized under the same process conditions.After deodorization,the oils optimized under water washing conditions were reduced by about 22% and the GEs content was increased to 1.73 times compared with the 3-MCPD ester content in general refining processes.The results of the study clarified that the removal of chloride ions in the oil refining process can reduce the formation of 3-MCPD esters,and provided a feasible method for the control of 3-MCPD esters in the oil refining process.(c)The refining and removal of oils,especially the deodorization of oils,will inevitably form 3-MCPD esters and GEs.In order to reduce the content of the two risk components in the refining oil as much as possible and improve the safety quality of the oil,it is necessary to study the removal method of 3-MCPD ester and GEs in the oil.In this paper,the effects and optimized conditions of the molecular distillation method for removing 3-MCPD esters and GEs from oils were studied.the result shows: Optimized molecular distillation conditions using a distillation temperature of 220?,a scraping speed of 230 r/min,and a feed rate of 50 d/min.The content of 3-MCPD ester and GEs in corn oil decreased from 2.686 and 5.909 mg/kg to 0.556 and 0.885 mg/kg,respectively.The removal rate can reach 79.3% and 85.0% respectively.Both can be reduced below the EU limit/recommended limit.However,the molecular distillation process will cause different degrees of loss of sterols and vitamins E in the oil,and the loss rates are 38.2% and 28.6%,respectively.It is clear that the molecular distillation method can be used as a reliable method for removing grease.For oils and fats with higher contents of 3-MCPD ester and GEs,two-stage molecular distillation can be used for deep removal.The removal rates of 3-MCPD ester and GEs reached 93%-96% and 91%-98%,respectively.The content of 3-MCPD ester and GEs decreased from 6.169-16.008 mg/kg and 7.004-56.399 mg/kg to 0.368-0.932 mg/kg and 0.545-0.900 mg/kg,respectively.It has reached the EU's strict limits(?1.25 mg/kg and ?1.0 mg/kg).But it will cause the loss of sterol and oryzanol in oils by 25%-41% and 11%-12%,and the vitamins E loss rate reaches 86%-89%.