鱼油微胶囊制备工艺优化及其理化性质研究

为了解决鱼油在食用过程中易氧化及带有鱼腥味等问题,以豌豆蛋白(PPI)-阿拉伯胶(GA)复合物为壁材,冷冻干燥制备鱼油微胶囊。通过正交试验研究了壁材质量分数、芯壁比、均质压力、PPI与GA质量比等4个因素对鱼油包埋率的影响,得到鱼油微胶囊制备的最佳工艺:壁材质量分数5%,PPI与GA质量比1∶1,均质压力50 MPa,芯壁比1∶2。最佳条件下鱼油微胶囊的包埋率78.10%、水分含量(1.94±0.08)%、休止角(41.40±0.25)°、堆积密度(0.11±0.02) g/cm3。利用气相色谱法测定鱼油包埋前后DHA的保留率为95.33%;通过热重分析,鱼油微胶囊的热稳定性良好。对鱼油微胶囊进行零级、一级反应方程式氧化动力学分析,并运用Vant’Hoff经验公式预测微胶囊产品的货架期,结果发现,在4℃贮藏条件下鱼油微胶囊的货架期为176 d。运用Avrami’s公式研究鱼油微胶囊的释放性能,结果表明高温、高湿条件下不利于芯材的保留。

Optimization of preparation process of fish oil microcapsules and study on their physicochemical properties

Fish oil has many dietary benefits,but due to their strong odors and rapid deterioration rates,their application in food formulation is limited. This article reported a systematic study of encapsulation of fish oil into PPI-GA microparticles by emulsification and subsequent freeze drying in order to protect it from lipid autoxidation and facilitate its incorporating into healthy food. According to the single factor experiment result,four factors and three levels experiments were designed with the encapsulation rate as index,and the optimized experimental conditions were as follows: wall material mass fraction 5%,mass ratio of PPI to GA 1 ∶1,homogenization pressure 50 MPa,and core-wall ratio 1 ∶2. Under this condition,the encapsulation rate of fish oil microcapsules was 78. 10%,the moisture content,angle of repose,and bulk density were( 1. 94± 0. 08) %,( 41. 40 ± 0. 25) ° and( 0. 11 ± 0. 02) g/cm3,respectively. the fish oil package was determined by gas chromatography. The retention rate of DHA before and after encapsulation was 95. 33%.The relationship between the quality of fish oil microcapsule products and temperature was analyze by TG analysis. The results showed that the pyrolysis process was divided into two stages,the first stage occurred at 189. 61-255. 10 ℃,when the microcapsule wall material underwent violent physicochemical reactions.The second stage occurred at 255. 10-396. 01 ℃,which was the accelerated stage of weightlessness,at this stage,the core material may be completely decomposed and finally carbonized. The fish oil microcapsule products were stored in a constant temperature incubator at 4,25 and 35 ℃ for 21 days,and the peroxide value was measured every 3 days. The Arrhenius empirical formula was used to analyze the oxidation kinetics of fish oil microcapsules and the Vant’Hoff empirical formula was used to predict the shelf life of the microcapsule products. The results showed that the shelf life of fish oil microcapsules under 4 ℃ storage conditions was 176 d,and the microencapsulated fish oil performed prolonged shelf life than normal fish oil.The releasing of fish oil microcapsule products under different temperature and humidity conditions was studied. An appropriate number of microcapsules was taken every 3 days to determine the core material retention rate,and the Avrami’s formula was used to analyze the core material release process. The results showed that with the increase of temperature and humidity,the release of fish oil microcapsules gradually increased,and high temperature and high humidity conditions were not conducive to the retention of core materials.