Use bioassay to create a standard spectrum of smell.

Distinguishing the difference between the aroma of pepperoni pizza and boiling cabbage is not as simple as it seems for everyone. Some have a heightened sense of smell and can be overwhelmed by aromas. Others suffer from smell blindness--anosmia--that could make the cabbage smell wonderful.

In the industrial world, we have to be able to distinguish between those with an ability to properly determine aromas and those who can't. Cornell University chemists (New York State Agricultural Experiment Station, Geneva, NY 14456) are finding out how to do this by standardizing the spectrum of smell. Scientists are developing aroma standards in the laboratory. Let's say you smell an essence oil like jasmine, which is a pure smell. Your ability to smell that jasmine is based on a small combination of olfactory receptor proteins. Those proteins produce a pattern that your brain would recognize.

But even finite aromas like jasmine are sensed by people in different ways. One reason for the large variation associated with olfactory acuity is anosmia. This smell blindness or insensitivity to the odor of a chemical or group of chemicals may occur in people with an otherwise normal olfactory sensitivity. Specific anosmia poses a challenge to researchers because it can distort data in sensory labs. A classic example of this sensory problem occurred when test subjects sniffed isobutyric acid, which smells like dirty socks or an unclean goat to most people. But there were testers who sensed that the isobutryic acid had a very pleasant fruity odor, like apples.

Experiments later revealed that the wayward individuals had a specific anosmia to isobutyric acid. The fruity smell they detected was the result of the byproducts and impurities usually found in commercial samples of the acid. If a company wants to make pine cleaner for bathrooms and inadvertently tests its product on a person with an anosmic sense of smell, that person may barely perceive the alpha pinen, the active chemical responsible for the smell. This means that most consumers will think the product smells too piney, according to the scientists.

Using a selective and sensitive bioassay for smells based on gas chromatography olfactometry, called CharmAnalysis, scientists have investigated the compounds responsible for specific anosmia. The researchers are attempting to correlate sensitivity to the chemicals to the olfactory receptor genetics. It might be possible to test people and categorize them for their valuable acumen by having them sniff a broad, standard set of aromas in just a few whiffs. The set will allow laboratories to easily screen out individuals with specific anosmia.

The researchers are using standard tests to sort out their testing subjects. They believe that they can accurately classify people as: hyperosmic (very sensitive), hyposmic (the baseline category) and anosmic. This will help other researchers conduct analyses.

Further information. Terry Acree or Jane Friedrich; phone: [phone]; fax: [phone]; email: [e-mail].