IDM ¦ Product development
Predicting creaminess of food
NIZO reports advances in laboratory methods
Helping food manufacturers analyse products in the lab is one
of NIZO’s areas of expertise. A recent publication reporting
research carried out as part of a NIZO/DSM collaboration
provides encouraging results for a new surface material that
can be used in devices that analyse the physical properties
of food. In this study, a hydrophilic gel made from whey protein isolate
(WPI) clearly discriminated between the friction behaviour of low and high
fat yogurts. This makes WPI gel a promising material for use in predicting
sensory mouthfeel and thereby speeding up product development.
To meet the increasing consumer interest in low-fat foods, food manufacturers
are designing foods that contain less fat, but that nevertheless
give the sensation of a full-fat product. However, any changes to the composition
of a product alter its physical properties. In yogurt for example,
the sensation of “creaminess” is due to the breaking up of fat globules.
Without fat you therefore need to mimic this feeling in the mouth.
Assessing the acceptability of new products
But how do manufacturers know if a new yogurt still provides the sensation
of creaminess? The most accurate way is to conduct taste tests
using consumer testing panels. This is relatively expensive and time-consuming
however: such tasters often need to be trained, and the training
20 · April 2020 ¦ international-dairy.com
and testing process can take several weeks or even months. The use of
panels is therefore not an ideal method at the early stages of product
development, when scientists are assessing different types of changes to
ingredients and how these changes will affect sensation in the mouth.
The perception of fat-related attributes such as creaminess is known
to involve the friction forces sensed in the mouth. Fortunately, these friction
forces can also be measured in the laboratory using devices that attempt
to mimic the movement of food against the tongue. These devices
– known as tribometers – can be used to predict whether a product is likely
to give more or less friction against the tongue, and therefore whether the
product’s so-called mouthfeel is likely to be acceptable to the consumer.
Pig’s tongues versus artificial surfaces
There are several different types of tribometers as well as several
types of surfaces used to mimic the tongue. Pig’s tongues have
been used at NIZO, as their surface characteristics are similar to
those of a human tongue. Pig’s tongues have several disadvantages
however, including their limited availability, rapid degradation of
the tissue, and variations between different tongues.
Artificial surfaces have therefore been developed, and commonly
used materials include silicone rubber and polydimethylsiloxane (PDMS).
These materials are shaped into plates which can then be placed in a
tribometer. The main advantage of PDMS is that the degree of surface
roughness can be changed by changing the degree of polymer crosslink