真空冷冻干燥与喷雾干燥长双歧杆菌的工艺比较研究

为有效延长双歧杆菌的保存期和耐受性，利用真空冷冻干燥及喷雾干燥法制备活性菌粉。研究两种干燥方法的工艺参数，并对干燥得到的活性菌粉性能进行比较。真空冷冻干燥法制备的长双歧杆菌活性菌粉的活菌数为7.98×109CFU/g、存活率90.9%、含水量3.8%，4℃保藏90d后活菌数为2.5×108CFU/g，菌粉的水溶性好；喷雾干燥法制备的活性菌粉的活菌数为4.4×109CFU/g、存活率82.2%、包埋率71.9%、含水量5.6%，4℃保藏90d后活菌数为4×108CFU/g，菌粉在水中的溶解时间较长。真空冷冻干燥成本较高、操作时间长、菌粉的保藏期较短；而喷雾干燥工艺简单、生产成本低、工作效率高，包埋的菌粉保藏期较长。

Comparison of Vacuum Freeze-Drying and Spray-Drying Processes for Active Bifidobacterium longum Powder Production

For long term storage and to improve its stress resistance,Bifidobacterium longum was made into active bacteria powder by vacuum freeze-drying or spray-drying.In this study,we first optimized the technological conditions for active Bifidobacterium longum powder production and then compared these two processes in term of bacterial survival rate,cost,and ease of operation.The viable count,survival rate,moisture and viable count after storage for 90 days at 4 ℃ of vacuum freezedried active Bifidobacterium longum powder were 7.98 × 109CFU/g,90.9%,3.8%,and 2.5 × 108CFU/g,respectively.The powder dissolved easily in water.In contrast,the viable count,survival rate,encapsulation efficiency,moisture and viable count after storage for 90 days at 4 ℃ of spray-dried Bifidobacterium longum powder were 4.4 × 109CFU/g,82.2%,71.9%,5.6% and 4 × 108CFU/g,respectively.It took longer time to dissolve in water when compared to vacuum-freeze dried powder.Vacuum freeze-drying was more complicated to operate,time-consuming and expensive than spray-drying.In conclusion,these two processes have both their advantages and disadvantages,which make them fit for different purposes.