T E S T I N G
TECH HELPS
GET THE MOST
OUT OF FOOD
With food becoming increasingly high tech, and consumers paying
extra attention to what they are putting into their bodies, analytical
equipment is becoming more important than ever.
Analytical equipment like the
Zetasizer analyses the particle size
of products at sub-micron range
and measures the surface charge
Postdoctoral research
fellow at Massey
University Dr Zhigao
Niu says utilising
analytical technology can be the
difference between a products
success or being overlooked on
the shelf.
One such instrument is the
Zetasizer. The Zetasizer analyses
the particle size of products at
sub-micron range and measures
the surface charge. Knowing what
both these are is very important
to researchers in the food industry
as this information is the key to
understanding how food will look,
taste, and feel on the palate as well
as how it will react on the shelf over
time.
This technology is particularly
useful for analysing milk and milk
powder. As New Zealand has a
large dairy industry, Dr Niu says
companies could benefit greatly
from paying more attention to
details like this.
The Zetasizer is also used in food
product areas such as edible
films, wine and beer, oil in water
emulsions, food flavourings
and coffee. The monitoring and
adapting of colloidal properties
have become common practice
as a way of ensuring products are
meeting customer demands and
enhancing their satisfaction.
Particle size is directly related
to how a customer perceives a
product and, in turn, the reputation
of a company. This is especially
noticeable in food where the
particle size changes the enjoyment
of the product such as coffee
grains milk powder.
Instruments in the Zetasizer range
can measure particle and molecular
size from a few nanometers to
several hundred nanometres
using dynamic light scattering;
zeta potential and electrophoretic
mobility using electrophoretic light
scattering; and molecular weight
using static light scattering.
The relationship between shelf
life and zeta potential has been
acknowledged for many years. As
the magnitude of the zeta potential
increases, so does the electrostatic
repulsion between neighbouring
particles.
The electrostatic stability of a food
product determines whether, by
the time the item is on the shelf,
its particles will be dispersed
evenly or whether it will become a
separated mixture which can look
unappealing to consumers.
In New Zealand many milk
companies use this machine
to understand how big the fat
particles are. The size of the
fat particles depends on the
homogenisation and species of
the milk. It also provides valuable
information about how the milk will
keep and behave once packaged
and on the shelf.
Smaller companies do
not have the funds for
this type of research, but
Dr Niu says this is where
universities and other
research institutes can assist
with collaboration.
“There are more and more
high-tech products in
the market. There are
22 APRIL / MAY 2020