Research Of Growth And Decline Regularity On 3-Chloropropane-1,2-Diol Ester In Roasted Flaxseed Oil

In recent years,the topic 3-Monochloro-1,2-propanediol ester(3-MCPD ester)is common occurrence in the world,which is a kind of contaminant in the oils.As one of non-mutritive ingredient and one matter,3-MCPD ester has underlying hazard to human body,study on the formation mechanism and the growth and decline regularity of 3-MCPD ester is of vital significance to the safety of plant oil.Object: A method gas chromatography-negative chemical ionization-mass spectrometry(GC-NCI-MS)was established to study the growth and decline regularity of 3-MCPD ester in roasted and refining process of flaxseed oil.To evaluate the risk of 3-MCPD ester in virgin flaxseed oil and to provide some theoretical basis for improving the refining process of flaxseed oil,and to better control the content of3-MCPD ester in refined flaxseed oil.Methods: The content of 3-MCPD ester in flaxseed oil of Xinjiang was detected by Gas chromatography-negative chemical ionization-mass spectrometry(GC-NCI-MS).Industrial refining was simulated in laboratory,combined with industrial refining to study the growth and decline regularity of3-MCPD ester in flaxseed oil.(1)A method,hydrolyzed by sodium methoxide-methanol,purified by solid phase extraction(SPE)using diatomaceous earth as the sorbent,derivatized with heptafluorobutyrylimidazole(HFBI)and combined with gas chromatography-mass spectrometry(GC-MS)was used in order to detecting the content of 3-MCPD ester in edible plant oils.The method showed good linear relationship in the range of0.50~2.50 mg/L(r=0.9942).The detection limit and quantification limit were 0.0255mg/kg and0.0933mg/kg respectively.The recovery rate was between 94.80%~104.62%,and the relative standard deviation was between 1.47%~5.23%.The method was easily operated with good sensitivity and repeatability,and it could meet the determination demand of 3-MCPD ester in edible plant oil.The content of 3-MCPD ester in several edible plant oil of Xinjiang was detected,and the results shown: 3-MCPD ester was found in all of edible plant oil with different concentration.Rapeseed oil,flaxseed oil,tomato seed oil,peanut oil,and grape seed oil were severely contaminated with 3-MCPD esters,and the content of3-MCPD esters were both higher than 0.4 mg/kg.The content of 3-MCPD esters in walnut oil,soybean oil and safflower oil were both lower than 0.4 mg/kg.(2)Gas chromatography-negative chemical ionization-mass spectrometry(GC-NCI-MS)was used in order to establishing a method for the content determination of 3-MCPD ester in flaxseed oil.The method showed good linear relationship in the range of 0.01~0.10 mg/L(r=0.9987).The detection limit and quantification limit were 5 ?g/kg and 20 ?g/kg,respectively.The recovery rate was between 80.47% and81.68%,and the relative standard deviation was between 5.60% and 8.35%.The content of 3-MCPD ester in flaxseed oil was detected,and the results showed that the content of 3-MCPD ester in three flaxseed oils was between 0.3077 and 1.2059 mg/kg.Compared with other oils,the content of 3-MCPD ester was at a moderate level.(3)The content of 3-MCPD ester in virgin flaxseed oil was detected,and the results shown: The lowtemperature of roasted flaxseed had no effect on the formation of 3-MCPD esters in virgin flaxseed oil.When heated at 160 °C to 200 °C,with the increase of oil temperature,the content of 3-MCPD ester in the virgin flaxseed oil was slightly increased.When heated at 200 °C,the heating time had slightly effect on the formation of 3-MCPD esters in virgin flaxseed oil.But at the same heating temperature,with the increase of chloride content,the content of 3-MCPD ester in the virgin flaxseed oil was significantly increased.(4)Industrial refining was simulated in laboratory.In the process of roasted flaxseed of flaxseed oil,when heated at 120 °C to 170 °C,with the increase of oil temperature,the content of 3-MCPD ester in the virgin flaxseed oil was increased from 0.093 mg/kg to 0.352 mg/kg.The flaxseed oil roasted temperature at160 °C was refined in the laboratory,the content of 3-MCPD ester was slightly increased after the process of degumming and neutralization,the content of 3-MCPD ester was decreased from 0.282 mg/kg to 0.212mg/kg.The content of 3-MCPD ester was increased to 0.374 mg/kg after of bleaching process.The content of 3-MCPD ester was significantly increased after deodorization,the content up to 0.849 mg/kg The results of different deodorization time and deodorization temperature on the formation of 3-MCPD ester in flaxseed oil showed that the content of 3-MCPD ester in flax oil increased gradually with the heating time under the heating condition of 220 °C,and reached the highest value after 2 h,the content of 3-MCPD ester reached 0.557 mg/kg.Under 180 °C and 200 °C heating conditions,the content of 3-MCPD ester in flaxseed oil increased linearly,reaching 0.403 mg/kg and 0.484 mg/kg respectively at 2.5 h,which did not reach the maximum value.(5)The content of 3-MCPD ester in different refining processes of flaxseed oil was detected,and the results shown: The 3-MCPD ester was largely formed in the process of roasted flaxseed and the content was 0.410 mg/kg.However,the 3-MCPD ester in flaxseed oil increased further after deodorization,reaching 0.610 mg/kg.This also shows that the roasted flaxseed process and deodorization of refining process are important processes on the formation of 3-MCPD ester in flaxseed oil.