Chemistry Reference
In-Depth Information
in addition to lactose, minerals and other desired key minor constituents.
However, a greater challenge is faced when drying powders of such high-
lactose content.
IV.5.2.
Chocolate
Lactose may be generally regarded as having a secondary role in milk
chocolate, its presence being largely opportunistic by virtue of being a con-
stituent of the milk powder used. However, attempts at explaining variations
in chocolate properties, especially viscosity, have led to greater scrutiny of the
functional quality of such dairy ingredients. When Aguilar and Ziegler (1995)
partially substituted sucrose in milk chocolate by lactose provided by whole
milk powder, the physical state of the lactose had important effects on
chocolate properties - higher concentrations of amorphous lactose reduced
chocolate viscosity, increased particle size of chocolate mass post-refining
and reduced the requirement for surface-active agents to achieve the desired
Casson yield value, while increasing the content of crystalline lactose had the
opposite effect.
Spray-dried whole milk powder (WMP), with its relatively low level of
free fat, is sub-optimal as a dairy ingredient for use in chocolate production
compared to roller-dried WMP. However, adapting our knowledge of lactose
behaviour may now be the basis of a technological approach to circumvent-
ing this problem. Baechler et al. (2005) showed that the phase diagram of
whole milk powder may be exploited to achieve greater functionality of
WMP for use in chocolate. They demonstrated that careful control of the
water activity of WMP before heating at 908C for 70 min could bring about a
desired release of free fat (
>
70% of total fat), while maintaining WMP in
powder form and avoiding the induction of browning. This release of free fat
onto the surface of WMP was correlated with increased lactose crystallization
in the
-form.
IV.6.
Role of Lactose in Microencapsulation
Microencapsulation involves the optimization of ingredient formulation and
process technology (homogenization, spray drying) to produce stable emul-
sions that may be spray dried to yield powder particles with defined char-
acteristics. The protection of an active ingredient (e.g., oils/fats that are
particularly susceptible to oxidation) either during processing, delivery or
subsequent storage is usually the objective. The process differs from conven-
tional whole milk powder production in that emulsion composition and
formation are finely tuned to take advantage of structural changes that
