The dehydrated lactose forms αH and αS were investigated by time- and temperature-resolved X-ray powder diffractometry and differential scanning calorimetry. We
found different X-ray structures for these two forms, which is probably related to the different dehydration processes. The
rapidly dehydrated form αH obviously has the same X-ray structure as the starting material α-lactose monohydrate, although the crystallinity is reduced.
A thermally induced transition of the αH-form into the αS-form was observed. This transition should allow one to “switch” between the physicochemical properties of the excipient,
which may be important for applications in pharmaceutical and food industries.
The use of dataloggers in food engineering is discussed in two examples. The first example describes the measurement of temperature and humidity in a bulk tank car during transport and unloading. In the case of wheat flour the relative humidity in the air raises from about 80% r.h. to values near 100% r.h. at the air compressors for pneumatical unloading start working. The second example shows the use of the datalogger in education on heat transfer. The device was fixed in an ice cream sample which was placed in a store at –25°C. The measured hardeningtime agrees well to theoretical heat transfer calculation.
Authors:H. K. Cammenga, L. O. Figura, and B. Zielasko
The glass transition of isomalt and its components, the enthalpy of solution (crystalline state, glassy state) and the enthalpy of melting are reported. From the measured data (solution enthalpy, enthalpy of fusion and heat capacities) a cycle like the BORN-HABER cycle can be constructed. It is possible to calculate the amounts of amorphous isomalt from measured solution enthalpies; however, the values obtained do not agree with those provided by X-ray powder diffraction studies.