Detection And Exposure Assessment Of 3-MCPD Ester In Edible Oils And Optimization Of Refining Process Of Camellia Oil

In recent year,chlorpropanol ester pollution has become a new safety issue and a hot topic worldwide,especially 3-monochloropropane-1,2-diol(3-MCPD)ester.Esterified forms of 3-MCPD can be found in edible oils and hot processed food.Previouce studies have demonstrated that the formation of 3-MCPD ester was associated with high temperature during refining process.Nowadays,the content of 3-MCPD ester in camellia oil was reported at a high level.This study started with the optimization of GC-MS indirect method for the analysis of 3-MCPD ester.We assessed the exposure of 3-MCPD ester based on whole population,investigated the formation law of 3-MCPD ester and optimized the camellia oil physical refining process for reduction of 3-MCPD ester formation.The main results were summarized as follows:1.The impurities in samples was extracted and treated with PSA solid-phase extraction purification steps.The GC-MS indirect method was validated by evaluating the recovery rate,sensitivity,linearity.The limit of detection and limit of quantitation of 3-MCPD ester is 0.03 mg/kg and 0.10 mg/kg,respectively.The average recoveries of 3-MCPD esters spiked at 0.25 mg/kg,1.0 mg/kg and 5.0 mg/kg in crude camellia oil ranged from 98.83%to 108.79%with a relative standard deviation less than 10%.Additionally,this method was applied to the refined palm oil sample of proficiency test 2642 of Food Analysis PerformanceAssessment Scheme(FAPAS)for the analysis of 3-MCPD esters.The value submitted(0.407 mg/kg)by this novel method falls well within the scope of specified "satisfactory" range(assigned value,0.579 mg/kg),with the limits of |z|?2.The result showed that the method has the merit of sensitiveness and accuracy,and satisfied the need of oil analysis.2.68 kinds of edible oil samples were collected from different markets and tested by this novel method.The results showed that the detection rate of 3-MCPD ester was 90%,the average content was 1.07 mg/kg,the highest was 5.86 mg/kg.The content of 3-MCPD ester in crude camellia oil(0.19 mg/kg)was significantly different from refined camellia oil(2.52 mg/kg).The exposure assessment of 3-MCPD ester in edible oils were evaluated basing on Monte Carlo simulation.All evaluation results were based the hypothesis that 3-MCPD ester 100%transfer into 3-MCPD in the human body and edible oils as the only source of dietary exposure of chemicals.The results showed that the average hazard indexes(HI)of 3-MCPD ester to 7-10 year old boys and girls were 1.257,1.024,indicating there was a risk but no immediate measures are required.The average HI of 3-MCPD ester to adolescent,adult,and the elderly people all below 1,indicating no risk for those people,at an acceptable level.3.The change of 3-MCPD ester in camellia oil samples at different refining steps was investigated.The results showed that the content of 3-MCPD ester was low during alkali refining,washing and decolorizing,but increased significantly after deodorization.Results demonstrated that the deodorization played an important part in the formation of 3-MCPD ester during camellia oil refining process.Then the deodorization of camellia oil was simulated at laboratory conditions.The effects of deodorizing temperature,deodorizing time,NaCl concentration and stripping steam volume on the formation of 3-MCPD esters in deodorizing camellia oil were investigated.The main factors of the formation 3-MCPD ester are deodorizing temperature,deodorizing time,NaCl concentration.The 3-MCPD ester content of the sample is the highest when the deodorizing temperature at 250?.With the increase of deodorization time or the content of NaCl in the sample,the yield of 3-MCPD ester increases.However,the amount of stripping steam has no effect on the formation of 3-MCPD ester.4.The modified refining process was optimized for the least 3-MCPD ester formation and acceptable refined camellia oil quality using response surface methodology(RSM)with five processing parameters:degumming moisture,degumming temperature,activated clay,deodorizing temperature and deodorizing time.The refining process parameters of minimum 3-MCPD ester production:degumming moisture 2.97%,degumming temperature 50.5 ?,activated clay content 2.69%,deodorizing temperature 230?,deodorizing time 90 min.The optimization resulted in 76.9%reduction of 3-MCPD esters from3.6 mg/kg in the conventional refining process of C factory to 0.83 mg/kg.Meanwhile,the main quality indexes of the camellia oil sample meet the requirements of the national standards.