food
TRANSCRIPT
o Introduction
o Previous work done
o Working of e-nose
o E-nose vs. Bio nose
o Applications
o Advantages
o Challenges involved
o Future aspects
o Conclusion
o References
o An electronic nose is a
device that identifies the
specific components of
an odor and analyzes its
chemical makeup to find
it.
o It consists of certain
mechanisms such as an
array of electronic
sensors for chemical
detection and artificial
neural network for pattern
recognition.
o E-nose was first suggested by K. Persaud and
George Dodd of Warwick University in 1982.
o Then afterwards in 1988, another professor of this
university named Julian Gardner conducted his
research on this.
o It then came into popular use after 1989.
o Since then, development of sensor array-based
instruments has been actively pursued in Asia,
Europe and North America.
GC-MS measures about 250 volatile organic
compounds, but is time-consuming and expensive.
Dogs just indicate healthy / sick and do not provide
additional insight.
Human noses have too low sensitivity.
Electronic noses are fast and cheap, making them
suitable for mass screening.
The electronic nose was
developed in order to mimic
the human olfaction.
Essentially, e-nose consists of
three major parts:
o Sample Delivery System
o Detection System
o Computing system
o The sample delivery system enables the delivery of
sample( volatile compounds).
o The detection system, which consists of a sensor
set, is the “reactive” part of the instrument. When in
contact with volatile compounds, the sensors
experience a change of electrical properties. Each
sensor is sensitive to all volatile molecules but each in
their specific way.
o The computing system works to combine the
responses of all the sensors which represent the input
for the data treatment; it then performs analysis and
provides results.
o In a typical e-nose, an air sample is pulled by a vacuum
pump through a tube into a small chamber housing the
electronic sensor array.
o A sample-handling unit exposes the sensors to the
odorant, producing a response as the VOCs interact
with the active material.
o The sensor response is recorded and delivered to the
Signal-processing unit.
o Then a washing gas such as alcohol is applied to the
array for a few seconds or a minute, so as to remove
the odorant mixture from the active material.
Based on the type of sensors employed, e-nose can
be classified into the following categories:
o Conductivity Sensors
o Polymer Sensors
o Piezoelectric Sensors
o FET Gas Sensors
o Optical Sensors
The more commonly
used sensors include
• metal oxide
semiconductors (MOS),
• conducting polymers
(CP),
• quartz crystal
microbalance, surface
• acoustic wave (SAW),
and field effect
transistors.
SENSOR SET
IN E NOSE
BIO- NOSE E-NOSE
1. It uses the lungs to bring the odor to
epithelium layer.
2. It has mucus, membrane and hair to
act as filter.
2. The human nose contains the
olfactory epithelium, which
contains millions of sensing cells
that interact with the odorous
molecules in unique ways.
1. It employs a pump to
smell the odor.
2. It has an inlet sampling
system that provides
filtration.
3. E-nose has a variety of
sensors that interact
differently with the samples
provided.
BIO NOSE E-NOSE
4. The human receptors convert
the chemical responses to
electronic nerve impulses
whose unique patterns are
propagated by neurons
through a complex network
before reaching the higher
brain for interpretation.
4. Similarly, the chemical sensors
in the E-nose react with the
sample and produce electrical
signals. A computer reads the
unique pattern of signals, and
interprets them with some form
of intelligent pattern
classification algorithm.
•The Cyranose 320 is a
handheld “electronic
nose” developed by
Cyrano Sciences of
Pasadena, California in
2000.
•Applications researched
using the Cyranose 320
includes the detection of
COPD, and other medical
conditions as well as
industrial applications
generally related to
quality control or
contamination detection.
The applications(current) of an electronic nose include:
Medical diagnosis and health monitoring
Environmental monitoring
Application in food industry
Detection of explosives
Space applications(NASA)
In research and development industries
In quality control laboratories
In process and production department
I. Respiratory disease diagnosis-
o Human breath contains thousands of volatile organic compounds (VOCs) in gas
phase.
o E-nose can diagnose respiratory infections such as pneumonia.
o It does so by comparing smell prints from the breath of a sick patient with those of
patients with standardized readings.
o It is also being studied as a diagnostic tool for lung cancer.
II. Urinary Tract infections-
o The e-nose as a potential diagnostic tool for patients affected with kidney diseases, by
distinguishing traces of blood in urine samples.
o E-nose is capable of distinguishing
between the breath of a healthy person
and a person with cancer.
o The device is especially promising
because it is able to detect cancer
before tumors become visible in X-
rays.
Environmental applications of electronic noses include:
1. analysis of fuel mixtures
2. detection of oil leaks
3. testing ground water for odours
4. identification of household odours
5. identification of toxic wastes
6. air quality monitoring
7. monitoring factory emissions etc.
Analysis of fruit ripening-
o Fruit ripening is associated with an
accumulation of aromatic volatiles during
ripening.
o Information from the noses can help in removal
of rotten fruits at the appropriate time.
o This can help in avoiding storage losses due to
rots and fruit diseases.
o Currently, this is the biggest market for e-nose.
Its applications include quality assessment in
food production and monitoring various food
items based on their odor.
JPL Electronic Nose (e-nose)-A Brief Summary:
o It is a full-time, continuously operating event monitor
used in the International Space Station.
o Designed to detect air contamination from spills and
leaks in the crew habitat
o Provides rapid, early identification and quantification
of atmospheric changes caused by chemical species to
which it has been trained.
o Can also be used to monitor cleanup processes after a
leak or a spill.
o The human sniffers are costly as compared to e-nose.
o Also detection of hazardous gases by them is not
possible.
o E-nose has wide range of sensitivity.
o Results obtained by e-nose are fast and more accurate.
o It is well- suited for repetitive or boring tasks.
o It can also detect substances which are not detected by
our human nose, like mercury.
o E-nose can only identify a standard set of odors
which is stored in its database.
o Though it is effective but still it can’t mimic the
complex human olfactory system exactly.
o They also have shorter lifetime because of the
sensors employed in them.
o Moreover, e-noses available in market are not
economical.
In the field of health and security:
o The quality control of food products as it could be
conveniently placed in food packaging to clearly
indicate when food has started to rot.
o It is used to detect bacterial contamination in the
food products.
o It can be used to detect the cancers like brain
and lung cancer.
o A more futuristic application of e-nose has been
recently proposed for telesurgery.
In the field of crime prevention:-
• The ability of the electronic nose to detect odorless
chemicals makes it ideal for use in the police force,
such as to detect drug odors despite other airborne
odors capable of confusing police dogs. However this
is unlikely in the mean time as the cost of the
electronic nose is too great and until its price drops
significantly it is unlikely to happen.
•It may also be used as a bomb detection method in
airports. Through careful placement of several or more
electronic noses and effective computer systems you
could triangulate the location of bombs to within a few
meters of their location in less than a few seconds
o An electronic nose is a system created to mimic the functioning
of human nose.
o Since the whole working is automatic, it can also be used by non
specialists.
o Although it has several advantages, yet it is still far from the
selectivity provided by a human nose.
o Basically, it is a tool provided to overcome the shortcomings of
human nose thus giving us more fast and accurate results.
o Future developments in the use of advanced sensor arrays and the
development of adaptive artificial neural networking techniques
will lead to superior electronic noses.
• http://en.wikipedia.org/wiki/Electronic_nose
• www.enose.info/environmental.html
• http://enose.jpl.nasa.gov
• http://science1.nasa.gov/2004/06oct_enose
• H. V. Shurmur, “The fifth sense: on the scent of
the electronic nose” IEEE Review, pp:- 59-98,
March 1990