两级分子蒸馏深度脱除油脂中3-氯丙醇酯和缩水甘油酯

Deep removal of 3-monochloro-1,2-propanediol esters and glycidyl esters in oils by two-stage molecular distillation

对3-氯丙醇(3-MCPD)酯和缩水甘油酯(GEs)含量超标幅度大的1个玉米油和2个稻米油样品分别进行两级分子蒸馏,研究两级分子蒸馏对油脂中3-MCPD酯和GEs的脱除效果,同时测定其对油脂中V_(E)、甾醇和谷维素含量的影响。结果表明:3个油脂样品中3-MCPD酯含量为6.169~16.008 mg/kg,超出欧盟建议限量(1.25 mg/kg)的3.94~11.81倍,GEs含量为7.004~56.399 mg/kg,超出欧盟限量(1.00 mg/kg)的6.00~55.40倍;经一级分子蒸馏,油脂中3-MCPD酯的脱除率为49%~68%,GEs脱除率为42%~90%;经二级分子蒸馏,油脂中3-MCPD酯和GEs的脱除率分别达到93%~96%和91%~98%,含量分别降低至0.368~0.932 mg/kg和0.545~0.900 mg/kg,均明显低于欧盟限量;经二级分子蒸馏,3个油脂样品V_(E)保留率为11%~14%,甾醇保留率为59%~75%,稻米油中谷维素保留率为88%~89%。采用两级分子蒸馏能实现油脂中高含量3-MCPD酯和GEs的深度脱除,但同时也会造成油脂中V_(E)、甾醇等活性成分的较严重损失。因此,可根据油脂中3-MCPD酯和GEs的超标程度合理选用一级分子蒸馏或两级分子蒸馏。

Two-stage molecular distillation was performed on one corn oil and two rice bran oil samples with excessive contents of 3-monochloro-1,2-propanediol esters(3-MCPD esters)and glycidyl esters(GEs),and the deep removal effects of two-stage molecular distillation on 3-MCPD esters and GEs in oil were studied,the effects on the contents of V_(E)、sterol and oryzanol were also studied.The results showed that the 3-MCPD esters content in the three oil samples(6.169-16.008 mg/kg)exceeded the EU recommended limit(1.25 mg/kg)by 3.94-11.81 times,and the GEs content(7.004-56.399 mg/kg)exceeded the EU limit(1.00 mg/kg)by 6.00-55.40 times.After one-stage molecular distillation,the removal rate of 3-MCPD esters was 49%-68%,and the removal rate of GEs was 42%-90%.After two-stage molecular distillation,the removal rates of 3-MCPD esters and GEs were 93%-96%and 91%-98%,respectively,with the contents 0.368-0.932 mg/kg and 0.545-0.900 mg/kg,which were lower than the EU limit.After two-stage molecular distillation,among the three oil samples,the sterol retention rate was 59%-75%,the V_(E) retention rate was 11%-14%,and the oryzanol retention rate in rice bran oil was 88%-89%.The use of two-stage molecular distillation could achieve efficient and deep removal of high content of 3-MCPD esters and GEs in oil,but it could also cause serious losses of active ingredients such as V_(E) and sterols in oils.One-stage molecular distillation or two-stage molecular distillation could be reasonably selected according to the degree of excess of 3-MCPD esters and GEs in oil.