响应面法优化叶酸微胶囊制备工艺及其初步应用研究

Optimizing the preparation process of folic acid microcapsules by response surface methodology and its preliminary application

以食用叶酸为芯材,明胶、阿拉伯胶为壁材,采用复凝聚法搭配真空冷冻干燥法对叶酸进行包埋,制备了一款叶酸微胶囊。以叶酸的包埋率和产率为评价指标,以壁芯比、壁材比、总壁材浓度、反应体系pH、反应时间和TG酶添加量为影响因素,通过单因素试验和响应面试验优化其制备工艺。结果表明,叶酸微胶囊最佳制备工艺条件为:以200 g反应体系总质量为基准,壁芯比1.8∶1、明胶:阿拉伯胶1∶1、总壁材浓度2.0%、反应体系pH 4.2、反应时间41.5 min、TG酶添加量150 mg,此时的包埋率和产率分别为86.8%、80.4%。叶酸微胶囊成品为浅黄色粉末,电镜下成囊情况良好,分布较为均匀,呈椭球形或短杆形,其长径为0.6~1.2μm、短径为0.3~0.5μm,整体饱满充实,无破裂、孔洞和褶皱出现。同时探究了叶酸微胶囊在馒头制作过程中的变化规律,结果表明微胶囊包埋的叶酸留存率为93.8%,比直接添加的叶酸留存率高21.4%,说明微胶囊对叶酸有很好的保护作用,可以通过添加叶酸微胶囊实现馒头中叶酸的营养强化。

A folic acid microcapsule was prepared by using eating folic acid as the core material and gelatin and gum arabic as the wall material. Taking the encapsulation rate and yield of folic acid as the evaluation index,wall-to-core ratio,wall material ratio,total wall material concentration,pH of the reaction system,reaction time and amount of TG enzyme amount as influencing factors,the preparation process was optimized through single factor tests and response surface tests. The optimal preparation process conditions were:based on the 200 g reaction system,walltocore ratio 1.8∶1,gelatin :gum arabic 1∶1,total wall material concentration 2.0%,pH value of the reaction system 4.2,reaction time 41.5 min,and the amount of TG enzyme 150 mg. Under the above conditions,the encapsulation rate and yield of folic acid microcapsules were 86.8% and 80.4%,respectively. The finished product of folic acid microcapsules is light yellow powder. Under the electron microscope,the capsule is in good condition,the microcapsules are distributed evenly and are ellipsoid or short rod-shaped. The long diameter is 0.6 ~ 1.2 μm and the short diameter is 0.3 ~ 0.5 μm. The capsule has no cracks,holes and folds. At the same time,the changes of folic acid microcapsules in the production process of steamed bread was explored. The results showed that retention rate of folic acid embedded in microcapsules was 93.8%,which was 21.4% higher than that of directly added folic acid,indicating that microcapsules had a good protection against folic acid. The nutritional enhancement of folic acid in steamed bread can be achieved by adding folic acid microcapsules.