Featured Research

from universities, journals, and other organizations

Electronic Nose Inspects Cheese, Hints At Human Sense Of Smell

Date:
October 1, 1998
Source:
Ohio State University
Summary:
Researchers at Ohio State University have shown that an electronic nose -- a computerized device that samples scents -- recognizes the unique flavors of different kinds of cheese.

COLUMBUS, Ohio -- Researchers at Ohio State University have shown that an electronic nose -- a computerized device that samples scents -- recognizes the unique flavors of different kinds of cheese.

Aside from determining the value of this technology for the food industry, this research may one day help scientists better understand the human sense of smell.

W. James Harper, professor of food science and technology at Ohio State, explained that most companies employ human sensory panels -- professional taste and smell-testers -- to inspect products such as foods and beverages for which scent and flavor indicate quality. After testing a few samples, however, humans lose the ability to differentiate between similar scents and flavors and must take a rest.

Not so with electronic noses, which can test thousands of samples per day. Still, the machines can’t independently gauge the quality of a scent or flavor. They can only compare it to what human noses and taste buds have previously deemed acceptable.

“An electronic nose is not a replacement for people -- it is a supplement,” said Harper. “It allows companies to run a large number of samples without worrying about fatigue.”

When electronic noses debuted commercially in 1995, the devices promised to test the quality of products ranging from foods to petrochemicals. Since then, few companies have embraced the expensive technology -- costs run as high as $100,000 per machine. That’s why Harper and Kuen-Da Jou, a graduate student, decided to find out whether the devices really work.

Compared to the senses of sight, hearing, and touch, scientists know relatively little about how humans smell and taste. Designers of electronic noses have tried to mimic human noses by linking together sensors that detect a variety of volatile compounds.

“We wanted to prove whether the technology was real -- whether we could differentiate between aromas and relate those differences back to the way humans discern smell. That was essential as a first step to determining whether these devices would be useful in industry and research,” said Harper.

The results appeared in a recent issue of the journal Milk Science International. Harper discussed the work last month at the 216th national meeting of the American Chemical Society in Boston.

Harper and Jou compared the opinions of a human sensory panel to the scent analysis of a commercially-available electronic nose. The panel rated five different types of Swiss cheeses according to scent and flavor.

After the panel finished its work, Harper and Jou studied the cheese samples with gas chromatography, a technique that separates gases into constituent chemicals. The analysis revealed that each cheese contained different amounts of four fatty acids. The researchers then fitted a commercially-available electronic nose with an artificial neural network that trained the device to scan the cheeses for these key fatty acids.

The electronic nose correctly discriminated among the cheeses. It noted that the cheese which panelists described as especially sharp smelled very different from the one they described as especially bland. The device also agreed with the human panelists that the other three cheeses -- one fat-free, one reduced-fat, and one sharp Swiss variety -- all contained similar amounts of the volatile compounds and would taste virtually the same.

Based on these preliminary results, Harper and Jou decided that the electronic nose differentiated between scents well enough to act as a research or quality-assurance tool. “As long as human panels set the standards, then the electronic nose provides a good basis for acceptance or rejection,” said Harper.

The researchers will continue this work, but so far they have observed in the machine a situation analogous to the way in which humans experience a scent -- in stages.

“A good human sensory panel will pick up what they call top notes, middle notes, and bottom notes. When people smell an aroma, they experience one sensation immediately, then another sensation later, and then another at the end,” explained Harper. “We suspect that compounds that are present in a sample in very low quantities but possess a very strong affinity bind to the sensors first. Those are the top notes. Then, compounds with lower affinity but much higher concentration -- the middle notes -- reach the sensors and replace the top notes. We don’t know exactly what’s happening with the bottom notes yet.”

That explains why some scents scramble the machine’s sensors. “Electronic noses have been used to pick up off-odors in beer, but they don’t work on whiskey. When a sample contains one compound such as alcohol in high concentrations, then the machine’s sensitivity for other compounds goes down,” said Harper.

An endowment from the dairy industry of Ohio funded this research, and Brewster Cheese Inc. of Brewster, Ohio, provided the cheeses. The commercially-available electronic nose Harper and Jou used was the Fox 2000 from Alpha M.O.S., a French instruments company.


Story Source:

The above story is based on materials provided by Ohio State University. Note: Materials may be edited for content and length.


Cite This Page:

Ohio State University. "Electronic Nose Inspects Cheese, Hints At Human Sense Of Smell." ScienceDaily. ScienceDaily, 1 October 1998. <www.sciencedaily.com/releases/1998/10/981001080211.htm>.
Ohio State University. (1998, October 1). Electronic Nose Inspects Cheese, Hints At Human Sense Of Smell. ScienceDaily. Retrieved September 22, 2014 from www.sciencedaily.com/releases/1998/10/981001080211.htm
Ohio State University. "Electronic Nose Inspects Cheese, Hints At Human Sense Of Smell." ScienceDaily. www.sciencedaily.com/releases/1998/10/981001080211.htm (accessed September 22, 2014).

Share This



More Matter & Energy News

Monday, September 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Thousands March in NYC Over Climate Change

Thousands March in NYC Over Climate Change

AP (Sep. 21, 2014) — Accompanied by drumbeats, wearing costumes and carrying signs, thousands of demonstrators filled the streets of Manhattan and other cities around the world on Sunday to urge policy makers to take action on climate change. (Sept. 21) Video provided by AP
Powered by NewsLook.com
What This MIT Sensor Could Mean For The Future Of Robotics

What This MIT Sensor Could Mean For The Future Of Robotics

Newsy (Sep. 20, 2014) — MIT researchers developed a light-based sensor that gives robots 100 times the sensitivity of a human finger, allowing for "unprecedented dexterity." Video provided by Newsy
Powered by NewsLook.com
MIT BioSuit A New Take On Traditional Spacesuits

MIT BioSuit A New Take On Traditional Spacesuits

Newsy (Sep. 19, 2014) — The MIT BioSuit could be an alternative to big, bulky traditional spacesuits, but the concept needs some work. Video provided by Newsy
Powered by NewsLook.com
New Music With Recycled Instruments at Colombia Fest

New Music With Recycled Instruments at Colombia Fest

AFP (Sep. 19, 2014) — Jars, bottles, caps and even a pizza box, recovered from the trash, were the elements used by four musical groups at the "RSFEST2014 Sonorities Recycling Festival", in Colombian city of Cali. Duration: 00:49 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins