乳木果液油中生物活性物质提取工艺的研究

Extraction of bioactive compounds from shea olein

以乳木果液油为原料,经甲酯化后得到低酸值的乳木果液油,通过转酯化把甘三酯转化为脂肪酸甲酯,通过分子蒸馏把脂肪酸甲酯和生物活性物质分为轻组分和重组分,重组分(生物活性物质)再经过溶剂结晶进一步提高生物活性物质含量。通过单因素实验确定较好的甲酯化工艺条件为:反应温度70℃,反应时间3 h,醇油质量比3∶10,浓硫酸添加量3%;在此条件下,乳木果液油的酸值(KOH)从56.1 mg/g降至2.1 mg/g,游离脂肪酸转化率达到96.3%。通过单因素实验确定的较佳分子蒸馏条件为:进料速率2 m L/min,刮膜转速250 r/min,蒸馏温度150℃,真空度0.1 Pa;在此条件下蒸馏,生物活性物质在重组分中的回收率达95.9%,生物活性物质含量可达68.8%。乳木果液油经过甲酯化、转酯化、分子蒸馏和结晶得到的产品中三萜醇和甾醇总含量可达69.80%,生物活性物质含量可达83.18%。

With shea olein as raw material,low acid value shea olein was obtained by methyl esterification,then triglyceride was transformed into fatty acid methyl ester by transesterification. After the fatty acid methyl ester and bioactive compounds were separated into light fraction and heavy fraction by molecular distillation,the heavy fraction（bioactive compounds） was crystallized with solvent to further improve the content of active compounds. The optimal methyl esterification conditions were determined by single factor experiment as follows： reaction temperature 70 ℃,reaction time 3 h,mass ratio of methanol to oil 3∶ 10,dosage of concentrated sulfuric acid 3%. Under these conditions,acid value of shea olein reduced from 56. 1mg KOH / g to 2. 1 mg KOH / g,and the conversion rate of free fatty acids reached 96. 3%. The optimal conditions of molecular distillation were obtained by single factor experiment as follows： feed rate 2 m L / min,scraper speed 250 r / min,distillation temperature 150 ℃,vacuum degree 0. 1 Pa. Under these conditions,the recovery of the bioactive compounds in heavy fraction was 95. 9% and the content of bioactive compounds was up to 68. 8%. By the methods of methyl esterification,transesterification,molecular distillation and crystallization,the total content of triterpene and sterol in the product could reach 69. 80%,and the content of bioactive compounds could achieve 83. 18%.