Chemistry Reference
In-Depth Information
Figure 11.17.
Solubilization process for probes 1 and 2 (of different hydrodynamic radius)
dispersed in caseinate and modified caseinates, evaluated from ESR spectra. 1: Probe 1 in
caseinate (
&
) and in maltosylated (
) or galactosylated (
~
) caseinates. 2: Probe 2 in caseinate
(D). Some values of the proportions in mobile probes are indicated on the graph (LeMeste et al.,
1991).
11.5.5.
Influence on the Quality of Low-Moisture Foods
The influence of molecular mobility and of glass transition on the
quality of low-moisture food products was reviewed by LeMeste et al.
(2002). Here, we will therefore recall the main conclusions and review the
newer literature, particularly when dealing with dairy products.
11.5.5.1.
Collapse, Caking, Agglomeration
Stickiness and caking are important phenomena to be taken into
account upon drying of dairy products and in handling and storage of their
powders. Structure collapse, which occurs during freeze- or air-drying, or
during the storage of dried products, hinges on the same process as stickiness.
While these phenomena are responsible for deterioration in the quality of
dairy powders, agglomeration - a controlled caking process - is used to
improve the appearance and handling of powders and their dispersibility in
water. From the evidence available in 2002, mainly based on studies on
carbohydrate model systems, we concluded (LeMeste et al., 2002) that struc-
tural collapse, stickiness and caking/agglomeration could be explained suc-
cessfully using the glass transition concept. The formation of bridges between
