油脂脱臭过程氯离子含量对3-氯丙醇酯和缩水甘油酯的影响

Effect of Chloride Ion Content on 3-Monochloro-1,2-Propanediol Ester and Glycidyl Esters during Soybean Oil Deodorization

对油脂脱臭用直接蒸汽水源中氯离子含量和待脱臭油脂中氯离子含量进行检测分析,并采用不同氯离子含量的直接蒸汽对油脂进行蒸馏脱臭,检测脱臭前后油脂中3-氯丙醇酯(3-monochloro-1,2-propanediol ester,3-MCPD酯)和缩水甘油酯(glycidylesters,GEs)含量及氯离子含量,研究油脂脱臭过程氯离子含量对脱臭油脂中3-MCPD酯和GEs的影响。结果表明:油脂脱臭用直接蒸汽中氯离子含量随其水源中氯离子含量增加而升高,水源中氯离子含量在对应饱和蒸汽中的保留率约为0.1%;当油脂脱臭用直接蒸汽水源中氯离子质量浓度达到50～200 mg/L时,脱臭油脂中3-MCPD酯含量大幅升高至低质量浓度氯离子水源(1～10 mg/L)脱臭油脂中含量的2.6倍,但脱臭油脂中氯离子含量并未升高;待脱臭油脂中氯离子含量升高会导致脱臭后油脂中3-MCPD酯和GEs含量的升高。在待脱臭油脂中添加质量浓度为100 mg/L的氯化钠溶液0.5～5 mL时(相当于油脂中添加量1～10 mg/kg),脱臭后油脂中3-MCPD酯和GEs生成量分别为4.49～7.84 mg/kg和14.88～19.84 mg/kg,是待脱臭油脂含量的5.5～9.5倍和5.8～7.7倍。因此,控制和减少油脂脱臭过程氯离子含量对降低脱臭油脂中3-MCPD酯和GEs含量有重要作用。

The purpose of the present study was to investigate the effect of chloride ion content on the contents 3-monochloro-1,2-propanediol esters （3-MCPD esters） and glycidyl esters （GES） during the deodorization of soybean oil. The chloride ion contents of the water source of steam used directly for the deodorization of soybean oil was analyzed. The deodorization was carried out by distillation with steams of different chloride ion contents and we determined the contents of chloride ion, 3-MCPD esters and GES in soybean oil before and after deodorization. The results showed that the chloride ion content in the steam increased with the increase of chloride ion content in the water, and the retention rate of chloride ion in the water was about 0.1%. When the content of chloride ion in the steam was increased from 1–10 to 50–200 mg/L, the content of 3-MCPD esters in deodorized oil was increased by 2.6 times, while the content of chloride ion in deodorized oil did not rise. Increasing chloride ion content in undeodorized oil resulted in increased contents of 3-MCPD ester and GEs after deodorization. The contents of 3-MCPD ester and GEs in deodorized oil were 4.49–7.84 and 14.88–19.84 mg/kg, respectively, when 0.5–5 mL of sodium chloride solution at a concentration of 100 mg/L （the final concentration in the oil was 1–10 mg/kg） was added before deodorization, which were 5.5–9.5 and 5.8–7.7 times higher than in undeodorized oil. Therefore, controlling or reducing the chloride ion content during the deodorization process plays an important role in reducing the contents of 3-MCPD ester and GEs in deodorized oil.