不同温度分子蒸馏脱酸处理对茶叶籽油馏出物和馏余物的影响

Effect on Distillate and Distillation Residue of Tea Seed Oil During Deacidification Treatment by Molecular Distillation at Different Temperatures

利用分子蒸馏技术对茶叶籽油进行脱酸处理,研究了不同蒸发面温度下分子蒸馏脱酸对馏出物及馏余物酸价及过氧化值的影响;采用Schaal烘箱加速法评价分子蒸馏脱酸处理后茶叶籽油的氧化稳定性;为分子蒸馏技术在茶叶籽油物理精炼规模化应用奠定基础。结果表明,采用分子蒸馏操作条件为进料流量120 mL/h,刮板转速50 r/min,蒸发面温度230℃,绝对压强4 Pa,冷循环温度8℃时,脱除茶叶籽油中的游离脂肪酸效果显著,馏出物质量所占比例仅6%,馏余物酸价由原来的3.09 mgKOH/g降至0.18 mgKOH/g,同时过氧化值也显著降低,由原来的3.52 mmol/kg降至0.45 mmol/kg;优于传统的碱炼脱酸工艺。加速试验表明氧化稳定性比未经分子蒸馏处理的茶叶籽油较佳。分子蒸馏技术在高档茶叶籽油的物理精炼具有一定的应用前景。

Molecular distillation has been used to remove free fatty acid from the tea seed oil in the paper. The effects of different molecular distillation evaporation surface temperatures on the acid value, as well as peroxide value of distillate and distillation residue have been researched. Schaal method was utilized to study the oxidation stability of tea seed oil which was pretreated by molecular distillation, in order to provide foundation for the large - scale application of molecular distillation in the tea seed oil＇s physical refinement. The experimental results showed that molecular distillation could transport the free fatty acid effectively; while this would have a high yield of heavy fractions on the operation condition as： material -feeding rate of 120 mL/h, agitating speed 50 r/min, distillation temperature 230 ℃, distillation pressure 4 Pa and cooling circulation temperature 8 ℃. On the above conditions, the distillate account for 6% only; the acid value of distillate residue was lowered to 0.18 mgKOH/g from 3.09 mgKOH/g after the removal of free fatty acid by molecular distillation; while the peroxide value was lowered to 0.45 mmol/kg from 3.52 mmol/kg, much better than traditional technology of normal alkali refining. The results showed that the oxidation stability of tea seed oil pretreated by molecular distillation was better than that of the primary degumming tea seed oil. In all, the application of molecular distillation in the physical refining of high grade tea seed oil exhibits a great potential.