Abstract: The change in the particle size of whole milk powder during rehydration was studied by particle size analysis. This study also determined the effect of rehydration temperature (30, 40 and 50 ℃) and milk powder particle size on the rehydration process. Results showed that the rehydration of whole milk powder was affected by both temperature and its particle size. The rehydration time at 50 ℃ was 50% and less than 7.5% as compared to that at 40 ℃ and 30 ℃, respectively. For whole milk powder prepared using the same process, the larger the particle size, the shorter the rehydration time, and after rehydration under the same conditions whole milk powders with different particle size distributions exhibited different particle size distributions.

Key words: particle size analysis; whole milk powder; particle size distribution; rehydration

摘要： 采用粒径分析法研究全脂乳粉再水化过程中的粒径变化以及再水化温度（30、40、50 ℃）、乳粉粒径 对全脂乳粉再水化过程的影响。结果表明：全脂乳粉的再水化受水化温度和乳粉粒径大小的影响，当水化温度为 50 ℃时，再水化时间是水温40 ℃时的50%，且不足水温30 ℃时再水化时间的7.5%；同种加工工艺下的全脂乳粉， 粒径越高其再水化时间越短，且粒径分布不同的全脂乳粉同种条件水化后其粒径分布不同。

关键词: 粒径分析；全脂乳粉；粒径分布；再水化