超高压均质制备大豆多肽纳米乳及其粒径和稳定性分析

Soybean Isolate Protein Hydrolysate Nanoemulsions Prepared by Ultra-High Pressure Homogenization:Size and Physical Stability

大豆多肽是具有营养、呈味、抗氧化等生物活性的新型多功能天然乳化剂,为开发大豆多肽在食品乳液中的应用,本研究探索了超高压均质技术制备大豆多肽纳米乳液的影响因素和加工效果。以大豆分离蛋白为原料酶法制备大豆多肽(Soybean protein isolate hydrolysates,SPIH),考察了多肽质量浓度、均质压力和循环次数对纳米乳平均粒径、粒度分布和物理稳定性的影响,在单因素实验基础上,以粒径和稳定性为指标,通过正交试验进行工艺优化,并应用粒度仪和原子力显微镜表征了其储存稳定性和和微观形貌。结果表明,各因素最佳水平为:20 mg/mL多肽质量浓度,140 MPa均质压力和5次循环,在此条件下制备得到粒径为178.8 nm,稳定性指数Ke=7.37%的纳米乳液。超高压均质法制备的大豆多肽纳米乳具有均匀的液滴分布并可稳定储存56 d以上,随多肽质量浓度增加纳米乳液滴聚集情况明显。研究为多肽乳化剂纳米乳液的制备和应用提供了参考。

Soybean peptide is a new type of multifunctional natural surfactant with biological activities such as nutrition,taste and antioxidant.In order to take better use of soybean peptide as emulsifier in food emulsions,soybean protein isolate hydrolysates(SPIH)were prepared by enzymolysis of soybean protein isolate,and SPIH-stabilized nanoemulsions were firstly prepared by ultra-high pressure homogenization(UHPH)in this study.The effects of emulsifier concentrations,homogenization pressure and cycle numbers on the average particle size,particle size distribution(PDI)and physical stability(Ke value)of nanoemulsions were explored.The three preparation conditions were optimized by orthogonal experiment compromising between the mean particle size and Ke value.Particle size analyzer and atomic force microscope(AFM)were applied to characterize the storage stability and microstructure of the nanoemulsion,respectively.Results showed that the optimal conditions were SPIH concentration 20 mg/mL,homogenization pressure 140 MPa and cycle numbers 5,while the nanoemulsion with particle size of 178.8 nm,Ke=7.37%was obtained under this condition,and stabilized for more than 56 d.AFM images showed that droplets of the nanoemulsion distributed uniformly and droplets aggregated when the peptide concentration increased.This study would provide a reference for the preparation and application of nanoemulsions with polypeptide emulsifiers.