新生儿配方液态乳的瓶内灭菌工艺优化

Optimization of Retort Process for Liquid Newborn Formula

为优化新生儿配方液态乳的瓶内灭菌工艺(Retort),以黏度为指标,采用单因素实验筛选最佳工艺条件,得到最适均质压力30 MPa,灭菌温度115℃,灭菌时间10 min。在此基础上,用正交试验进一步优化这3个参数,得到最优工艺参数为均质压力20 MPa,灭菌温度115℃,灭菌时间8 min。比较用两种工艺参数生产的产品粒径、黏度和色差(ΔE),结果表明:用正交试验优化的工艺参数生产的产品稳定性更好。对比正交优化的瓶内灭菌新生儿配方液态乳(Retort液态乳)与UHT新生儿配方液态乳(UHT液态乳)的安全性,结果表明:Retort液态乳的菌落总数为0 CFU/mL,嗜热需氧芽孢数较低。采用扫描电镜(SEM)和激光共聚焦显微镜(CLSM)观察Retort液态乳和UHT液态乳的蛋白质和脂肪微观结构,发现Retort液态乳的蛋白质交联结构更加致密,变性程度较小;脂肪球的数量较多,尺寸较小。结论:Retort工艺灭菌效果更好,更适于新生儿配方液态乳的灭菌,这将为生产更加安全、营养的母乳替代品提供基础数据。

In order to optimize Retort process for liquid newborn formula,a single factor experiment was used to screen the optimum process conditions with viscosity as the index.The optimal homogeneous pressure was 30 MPa,sterilization temperature was 115℃,and sterilization time was 10 min.On this basis,orthogonal experiments were used to further optimize three parameters,and the optimum process parameters were obtained as homogeneous pressure 20 MPa,steril ization temperature 115℃,and sterilization time 8 min,the particle size,viscosity and color difference(ΔE)of the products produced by the two process parameters are compared,the results show that the product produced by the process parameters optimized by the orthogonal experiment has better stability.By comparing the safety of the orthogonal optimized Retort liquid newborn formula with UHT liquid newborn formula,the results showed that the aerobic plate count of Retort product was 0 CFU/mL,and the number of thermophilic aerobic spores was lower.Scanning electron microscope(SEM)and laser confocal microscope(CLSM)were used to compare the microstructures of protein and fat between Retort liquid formula and UHT liquid newborn formula.Retort liquid formula protein had a denser network structure and less denaturation;the number of fat globules was more and the size was smaller.Therefore,Retort process has a better sterilization effect and is more suitable for the sterilization of liquid newborn formula,which will lay the foundation for providing safer and more nutritious breast milk substitute for newborn infants.