Summary FPE-32306: Food Digestion: Ingestion and Structure Breakdown

Measuring oral processing behavior & bolus properties
Methods for oral processing
 Video recordings
o Dots on face
o Noldus: Chews,
swallows, eatng
duraton
o Kinovea: Number of
chews, chewing rate,
consumpton tme
 Electromyography (EMG)
o Contracton of jaw
muscles
o Total muscle actvity, muscle actvity per chew, vertcal movement and
number of chews.
 Videofuorography
o Video
o Focus on swallowing process over tme
o Identfy anatomical abnormalites
o Follows swallowing process, expensive, contrast fuid is needed
 Magnetc resonance imaging
o Tracking of food movements
o High spatal resoluton, only liquids, subjects lay down (artfcial), invasive
technique, expensive method
 Pressure sensors
o Dental implants measuring pressure during mastcaton
o Measuring bite force, high burden to subject, limited number of subjects

Consumer groups:
 Young vs. old (consumpton tme elderly > young)
 Asian vs. caucasion
 Male vs. female (bite size of males > females)

Food texture afects the eatng rate. For hard foods a lower eatng rate is observed than for
soft foods. The eatng rate afects food intake.

When consistency (proportonal to viscosity) goes up, the eatng rate goes down and
consumpton tme goes up.
Hard food  more chews and earlier sataton

Short duraton eaters have a diferent swallowing threshold.

, Advantages of video recordings disadvantages
Golden standard when videos are rated by Data processing is tme consuming
two assessors
Detailed informaton about eatng behavior: No informaton on tongue movement
consumpton tme, number of chews,
chewing rate
Suitable to measure eatng behavior during Swallowing points are difcult to obtain
an entre meal
Non-invasive for partcipant

Diferences in eatng behaviour  short and long eatng tme, which does not give
diferences in muscle actvity

Advantages of EMG Disadvantages
Precise measurement Mildly invasive for partcipants
Suitable to measure eatng behaviour Knowledge on measuring locatons needed
during an entre meal
Only method that quantfes muscle actvity Data processing is tme consuming

Advantages Videofuorography Disadvantages
Follows swallowing process Expensive method
Contrast fuid needed

Advantages MRI Disadvantages
High spatal resoluton Only liquids
Subject lay down
Invasive technique
Expensive method



Methods to quantfy bolus propertes
 Partcle size analysis
 Rheology
 Mechanical propertes
 Tribology
 Saliva content

Microstructure can determine mechanical propertes and infuence oral breakdown
behaviour.

Analysis of bolus propertess Partcle
Mastcaton duraton  number of partcles increases and partcle size decreases

, + precise measurement / - only informaton about food propertes, measurement should
take place immediately after expectoraton, only for solid foods

Rheology of bolus
Viscosity changes over mastcaton tme
Advantages Disadvantages
Flow of food Only informaton about food propertes
Precise measurement Measurement should take place
immediately after expectoraton
No interferences by individual variaton

Mechanical propertes during mastcaton
Firmness, adhesiveness and cohesiveness

Adhesiveness increases during mastcaton, frmness decreases

Advantages Disadvantages
Breakdown behaviour Only informaton about food propertes
Precise measurement Combinaton of mechanical methods
required
No interferences by individual variaton Measurement should take place
immediately after expectoraton

Tribology
The fricton, wear and lubricaton of interactng surfaces
Saliva provides a lubricaton flm on oral surfaces – low fricton coefcient: good lubricant

Advantages Disadvantages
Fricton of food Only informaton about food propertes
Precise measurement Surface property  fricton coefcient
depends on tribo-pair (propertes of surface
of the tribometer)
No interferences by individual variaton

When fricton force goes up, the perceived smoothness goes down.
When viscous force goes up, the perceived thickness goes up.