Chemistry Reference
In-Depth Information
of emulsions are crucial in terms of the achieved microstructure and its
stability during storage, what has become clear is that oral processes
are equally (if not more) important. The reason for this is that it is the
interplay between oral processing and the structure of the food emul-
sion that determine its sensory attributes and thus consumer acceptance.
This section will concentrate on the in-mouth behaviour of emulsions
in general and, to an extent, how this affects their perception.
The mouth is a device where digestive processes commence, and
despite being used every day, very few people appreciate the complex-
ity of the oral cavity and of the processes occurring during mastication.
Traditionally, this area of work has appeared in physiology and dentistry
journals with sporadic and non-conclusive information on the physic-
ochemical transformations of food in the oral cavity. Recently, there
has been an appreciation that a thorough understanding of the in-mouth
behaviour of food products is required to be able to design novel food
products and also develop respective instrumental methods with which
to test them. As such, journal articles and topic chapters have recently
appeared in the food-related literature (Chen, 2009; Van Der Bilt, 2009;
van Vliet
et al
., 2009).
In Fig. 9.2, a schematic diagram of the oral cavity is shown. In prin-
ciple, the oral cavity is similar for all individuals, but significant differ-
ences do exist based on gender, age or health status; a normal mouthful
of water for male adults is 30
8.1 g for females
(Hiiemae
et al
., 1996). The amount of food decreases when moving
from liquids to soft solids and to hard solids; for example, the average
mouthful for males is 13.1
±
10.1 g and 25.2
±
2.3 g for bananas and
peanuts, respectively. The reason for this is probably due to the increased
difficulty of breakdown.
Eating is a mixture of complex coordinated movements involving the
complex coordinated motions of the jaw, tongue and inner cheeks (Lund,
1991). Chewing patterns are rhythmic-periodic differing between indi-
viduals, resulting in three-dimensional motions of the ingested foods.
±
4.0 g and 5.5
±
9.3.1
Different stages and phenomena during oral processing
Significant efforts have been devoted towards understanding the physi-
ological mechanisms occurring during eating. Oral processing of foods
is highly dependent upon the structure/consistency of the food products
themselves. For solid products, discrete stages in the mastication have
been identified (Hiiemae and Palmer, 1999):
stage I transport
,inwhich
food is ingested and positioned on the occlusal table, where reduction to
an appropriate size, if required, is achieved;
stage II transport
,inwhich
a bolus is formed by moving food distally through the pillars and lastly
the
hypopharyngeal transit time
, in which the bolus is swallowed. Using
