为解决目前油脂微胶囊在高载量条件下包埋效率低、储藏稳定性不佳、粉体流动性能差等问题,本研究以酪蛋白酸钠与低聚异麦芽糖为原料通过湿法制备美拉德反应产物,以其为壁材,通过高压均质和喷雾干燥法对以中链甘油酯为主要组分的混合油脂进行包埋,最后对混合油脂微胶囊理化指标进行分析。通过单因素实验确定了美拉德反应产物制备最佳工艺条件:酪蛋白酸钠浓度为7%(w/v),酪蛋白酸钠与低聚异麦芽糖的比例为1:3(w/w),反应时间为120 min,反应温度为80℃,pH为8.0。在乳化阶段,同时添加2%单甘油脂肪酸酯与1%蔗糖脂肪酸酯,采用40与18 MPa二次均质,制得油脂载量高达68%(w/w)混合油脂微胶囊,其表面油和包埋率分别为3.01%和95.66%,卡尔系数和豪斯比分别为7和1.08。扫描电镜观察混合油脂微胶囊内外结构光滑致密,对混合油脂有良好的保护作用。60℃下贮藏30 d后,混合油脂微胶囊过氧化值仅9.06 mmol/kg,油脂保留率达90.57%。表明美拉德反应产物能有效保护芯材成分,抗氧化性能较强,为工业生产提供一定的工业指导方案。
Nowadays,high load oil microcapsules still face the problems such as poor physical and chemical properties,low microencapsulation efficiency,poor flowability and storage stability. In order to overcome these disadvantages,in this study,the Maillard reaction products(MRPs)was prepared by wet method with sodium caseinate and isomaltooligosaccharide,and then MRPs were adopted as wall material for microencapsulating mixed oil,which contained mainly medium chain triglycerides. The microcapsules were prepared with high pressure homogenization and spray drying. The optimal parameters were as follows for Maillard reaction:Sodium caseinate concentration was 7%,the mass ratio of sodium caseinate to isomaltooligosaccharide was 1:3 (g/g),the reaction time was 120 min,pH was 8.0,and reaction temperature was 80℃. For emulsification,2% glycerin monostearate and 1% sucrose fatty acid ester were added as emulsifiers followed by two-stage high pressure homogenization(40 and 18 MPa respectively). The surface oil and microencapsulation efficiency of the microcapsules were 3.01% and 95.66%,respectively.Carr's index and Hausner ratio of the microcapsules were 7 and 1.08,respectively. Besides,the scanning electron microscopyimage of the powder showed that the internal and external structure was smooth and compact. After storage at 60℃ for 30 days,the peroxide value of the mixed oil microcapsule was only 9.06 mmol/kg,and the oil retention rate was 90.57%.The results showed that MRPs can effectively protect the core material components and have a strong antioxidant property. Therefore,this study provides certain industrial guidance value.