Dairy Processing - January/February 2023 - 34

FORMULATIONS
functionality. This is important for influencing the texture,
mouthfeel and viscosity of the product. In general, the greater
the water content, the more " fluid " the product. Viscosity
increases as water content decreases or gets bound up by
other ingredients.
In fluid products, such as milk, dairy beverages and
drinkable yogurt, water is somewhat free flowing. These
products are all liquids, with the water component functioning
as a solvent or base for the solids, which remain in solution
as a result of inherent and added emulsifiers and added
hydrocolloids, as well as the process of homogenization. These
technologies are usually enough to manage the moisture in
liquid products so that there's no separation or sedimentation.
But it's the water in semi-solid and solid dairy foods, such
as cheese, ice cream, sour cream and yogurt, that needs to
be carefully managed for best consistency. Formulators often
rely on hydrocolloids to do this. This function is alluded to in
the name, where the prefix " hydro " means water and " colloid "
means a gelatinous substance.
In general, hydrocolloids are hydrophilic, high-molecular
weight compounds, usually with colloidal properties. Many
are polysaccharides, e.g., fibers, starches, gums, etc.; however,
some proteins, such as gelatin, as well as specialty proteins
derived from eggs and milk, are considered hydrocolloids.
Their primary function is thickening or gelation, while
secondary functions include aeration, emulsification,
encapsulation and suspension.
In dairy products, hydrocolloids are most often used to
stabilize, thicken or gel the system. Hydrocolloids work in
combination with carbohydrate, protein and fat components
in the dairy system. Blends are common, as they work
synergistically to achieve texture and stability goals with
34 JAN-FEB 2023 | DAIRYPROCESSING.COM
lower total addition levels. Thus, hydrocolloid blends may
reduce formulation costs.
Economics are always a product development
consideration. Hydrocolloids have proven to have a positive
impact on the bottom line - remember, their primary function is
to keep water in the system. This improves yields and profits.
Hydrocolloids also play an important role in keeping
ingredients stable in dairy product systems. This includes
identifiable pieces such as nuts, superfruits and cereals, such
as oats in yogurt, as well as vitamins, minerals and other
nutrients, including fiber and protein.
By definition, all hydrocolloids bind water. After that, they
vary in functionality and long-term performance. For example,
some hydrocolloids form thermoreversible gels, where
gelation occurs after the hydrocolloid dissolves in solution
and is cooled. When heat is applied, the gel melts or dissolves.
This is best exemplified by gelatin dessert, which melts in the
mouth at body temperature. Gelation temperature and melting
point varies by hydrocolloid.
Other hydrocolloids form non-thermoreversible gels, also
called thermally irreversible gels, and will not liquefy when
heated. They may soften or shrink, which is also referred to
as retrograde. In other words, the gel remains mostly intact
once formed.
There also are some hydrocolloids that do not form any
type of gel on their own, but will do so in the presence of
other compounds. The challenge lies in finding the right
balance between the different gelling characteristics. This
allows for products with superior moisture retention and
desirable mouthfeel and texture.
Xanthan gum, for example, is produced by microbial
fermentation. It is a non-gelling hydrocolloid that hydrates
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Dairy Processing - January/February 2023

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