[Effect of crystalline metastasis of lactose on hardness of compressed baby milk powder].

The purpose of this study was to examine the relationship between the crystalline metastasis of lactose, which is a main component baby milk powder, and the hardness of baby milk powder compressed by humidification followed by drying. Because baby milk powder is manufactured using a spray dryer, lactose in compressed baby milk powder exists in an amorphous (solid dispersion) form. X-ray diffraction measurement showed that this amorphous lactose metastasized to ß-form crystalline lactose, and thereafter metastasized to the α-form during the humidification-drying process. As a result of this crystalline metastasis, the hardness of the compressed baby milk powder increased, and then decreased. Furthermore, scanning electron microscopy (SEM) showed bridging structures between the particles increased and then decreased during the humidification-drying process. This showed that bridging structures between the particles produced by crystalline metastasis of lactose as a result of the humidification-drying process, which leads to an increase in the hardness of the compressed baby milk powder. These results show that the necessary degree of hardness of the porous compressed baby milk powder (necessary for packaging and transportation) resulted from the humidification-drying process.

[Making tablets of powdered milk and the physical properties].

Compressed baby milk powder has proven to be very convenient for parents due to the ease with which it can be handled, and the fact that use of a measuring scoop is not necessary. The purpose of this study was to develop a compressed baby milk powder and analyze the resulting physical properties. The basic production process consisted of the following steps: 1) molding milk powder by low compression pressure, 2) humidification at 25°C·97%RH and 3) drying with use of a desiccant. No chemical additives were used for solidification; therefore the chemical composition of the compressed milk powder is identical to the base milk powder. The important properties of the compressed milk powder are both ready solubility and the strength of the solid. The compressed milk powder obtained at low pressure was too brittle for practical use, but the strength was increased by humidification followed by drying. During the humidification process, the powder particles located close to the surface of the compressed milk powder partially dissolve resulting in bridging structures between the particles, leading to an increase in strength. Both specific surface area and the volume ratio of the compressed milk powder decreased. Testing showed that caking between the particles occurred following humidification, and that the volume of caking affected the ease with which the compressed milk powder dissolves in water.