Chemistry Reference
In-Depth Information
10.2
DESIGN AND CONTROL OF MATERIAL PROPERTIES
OF FOODS INSIDE PEOPLE
If we are to construct healthy everyday foods, we need to start out by
considering what happens inside the body. The three major stages worth
considering are the mouth, the stomach, and the intestine. The processes
that occur and the rheological considerations that need to be made are
different for these three stages.
10.2.1
Oral perception of foods
Once food has entered the mouth, it is comminuted by mastication and
chewing, which allows the release of flavour and for the texture to be
experienced. As this breakdown proceeds, the coupling of mechani-
cal, thermal and chemical reactions, as well as wetting by saliva, leads
to the formation of a food bolus (Hutchings and Lillford, 1988). The
bolus is processed until a threshold of size distribution and lubrica-
tion is achieved (Lillford, 2000). This processing not only occurs upon
ingestion of solids, where its effect is rather intuitive (reduction of par-
ticle size distribution (Peyron
et al
., 2004), lubrication and hydration
(Bongaerts
et al
., 2007)), but also occurs upon ingestion of soft solids
and liquids, where the effects are more related to the tasting of aroma
and the perception of texture(Kokini and Cussler, 1983).
Kokini and others (Kokini, 1987; Kokini, 1994; Kokini and Cussler,
1983) developed a creaminess 'equation' linking the perception of
creaminess (intuitively related to fat content) with other sensory at-
tributes from trained panellists such as thickness (related to the rheolog-
ical properties), smoothness (related to the particle size in the system)
and slipperiness (related to the friction properties). This relationship
has been formulated in two studies (Kokini and Cussler, 1983; Kokini,
1994) as follows:
thickness
0
.
54
smoothness
0
.
82
Creaminess
∝
·
(10.1)
or
=
.
·
+
.
·
Creaminess
0
54
log(thickness)
1
56
log(smoothness)
+
.
·
0
32
log(slipperiness)
(10.2)
The fact that a strongly hedonic sensory attribute such as creaminess
can be explained by these attributes suggests that creaminess is not only
controlled by the rheology of the product (Malone
et al
., 2003a; Akhtar
