Download Development of a Simple Device for “Oral” Tribology and Food

Development of a Simple Device for “Oral”
Tribology and Food Lubrication Studies
Jianshe Chen and Zhenyu Liu
School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, UK
Introduction
Aims
• To develop a simple device based on the Texture Analyser
for friction and lubrication measurements;
• To test the reliability of the device for food applications.
“Oral” tribology or oral lubrication has recently been recognised as
critically important in the dynamics of food oral processing and
sensory perception. In the past decade, there has been increasing
interests in the lubrication/tribology behaviour of food/saliva
systems. Growing evidence shows that food and saliva mixture
affects the resistance of tongue moving against the hard palate and
the sensation of the textural and other sensory properties. However,
tribology studies are often hindered for food applications due to
high costs of a commercial tribometer. Therefore, to establish a
cheap alternative device is needed and greatly desirable.
Waterbath
A lay-down
texture
analyser
Ball disc sliding against
silicone rubber
Measured friction force for stainless
ball against silicone rubber with
water as lubricant at various sliding
speed (load 327 g; 30 oC).
Load cell
connector
Steel balls
(Ф5mm)
Upside-down disc
Measured friction forces with
syrup solutions as lubricant
(0.3 mm/s, load 327 g, 30 oC).
Tests were conducted for
the reliability of the device,
using samples systems
published by de Vicente et
al (2006). Shown on right
are modified Stribeck curves
of
friction
coefficient
against sliding speed and
speed*viscosity, agreeable
with published results.
The triboplatform
A lay-down texture analyser with a three-ballsdisc connected to its load cell. The balls slide
against the silicone rubber surface at a
controlled speed. A thin layer of fluid was added
to the top of the substrate. The tribo-base was
connected with a water circulation for
temperature control.
Decreased friction coefficient at
increased sliding speed for various syrup
solutions.
Friction curves merge into a pattern
with an identifiable minimum.
Discussion and conclusions
 Current experimental set-up is proved to be feasible and reliable for
friction and lubrication studies;
 The friction was purely sliding with no contribution from rolling friction;
 Sliding speed varies from 0.01 mm/s to as high as 40 mm/s;
 Choice of substrate surfaces is flexible, according to research need ,
from stainless steel to silicone gel, from smooth to specifically textured;
 The device is easy to operate and its cost is only a small fraction of
that of a commercial tribometer. The device will be extremely useful for
food lubrication studies with a small budget.
References
J. Chen and J.R. Stokes (2012). Rheology and tribology: two distinctive regimes of food texture sensation. Trends in Food science &
Technology, 25, 4-12.
J. De Vicente, J.R. Stokes and H.A. Spikes (2006). Soft lubrication of model hydrocolloids. Food Hydrocolloids, 20, 483-491.