核桃油的分子蒸馏法脱酸、脱塑工艺条件优化Optimizaiton of deacidification and deplasticization of walnut oil by molecular distillation

为了提高核桃油产品品质，采用分子蒸馏法对核桃油中的游离脂肪酸和塑化剂(DBP、DEHP、DINP)进行脱除，并兼顾营养物质的保留。通过单因素实验和正交实验对核桃油中脱酸、脱塑条件进行优化。结果表明：进料速率和蒸馏温度对营养物质和DBP的影响较为显著，蒸馏温度和刮膜转速对于游离脂肪酸和DEHP的脱除影响更大；最佳脱酸、脱塑工艺条件为真空度0.1 Pa、蒸馏温度170 ℃、进料速率600 mL/h、刮膜转速350 r/min，在此条件下核桃油酸值(KOH)由1.08 mg/g降为0.057 mg/g，DBP含量由1.54 mg/kg降为0.12 mg/kg，DEHP含量由4.83 mg/kg降为0.98 mg/kg，DINP均为未检出，维生素E及甾醇的综合保留率达到82.77%。综上，所优化的条件可以将塑化剂含量降至标准要求范围内，可大幅降低酸值，且较好地实现了对维生素E和甾醇的保留。 In order to improve the quality of walnut oil, the molecular distillation technology was used to remove free fatty acids and plasticizers(DBP, DEHP, DINP) from walnut oil, meanwhile, taking into account the retention of nutrients. The deacidification and deplasticization conditions of walnut oil were optimized by single factor experiment and orthogonal experiment. The results showed that the feeding rate and distillation temperature had a significant effect on the nutrient and DBP, and the distillation temperature and scraping speed had a greater effect on the removal of free fatty acids and DEHP. The optimal conditions were as follows: vacuum degree 0.1 Pa, distillation temperature 170 ℃, feeding rate 600 mL/h, and scraping speed 350 r/min. Under these conditions, the acid value of walnut oil decreased from 1.08 mgKOH/g to 0.057 mgKOH/g, the content of DBP decreased from 1.54 mg/kg to 0.12 mg/kg, the content of DEHP decreased from 4.83 mg/kg to 0.98 mg/kg, and the content of DINP was not detected. The comprehensive retention rate of vitamin E and sterol reached 82.77%. In summary, the optimized conditions can reduce the plasticizer content to within the standard, get a significant reduction of acid value, and achieve a better retention of vitamin E and sterol.