'Fingerprinter' tells when and why foods lose taste

A major food commodities corporation has developed a technique that measures taste in order to take it away.

Central Soya Company wants to keep its soy oil as bland as possible. That's how customers like Nabisco and Frito-Lay like it, the company says.

Mark O. Flanagan, vice-president of the Refined Oil Division of the $2 billion Fort Wayne, Ind., company says Central Soya's customers use soy oil to make margarine, mayonnaise, cooking oil, salad oil, and shortenings. The less the flavor the soy oil has, the less there is to compete with flavors food-processing customers are trying to build into their foodstuffs.

The technique is called ''fingerprinting.'' It was developed by Dr. Harold P. Dupuy, a professor at Virginia Polytechnic Institute (VPI). Fingerprinting produces computer-generated profiles that instantly tell companies how bland their soy oil is, or why it's not as bland as they would like. Fingerprinting is not restricted to soy oil. Mr. Dupuy says the technique can assess the flavor quality of spices, cereals, and dairy products as well.

''VPI is using the method to examine off-flavors in fish. This is one of the greatest problems in developing aquaculture as a viable food industry. Our goal is to determine the chemical composition and the origin of compounds that cause off-flavors,'' Mr. Dupuy says.

The process measures a food's ''volatiles'' - chemical molecules that evaporate to produce odors or aromas. Mr. Dupuy says the process was used to detect the reason a new strain of rice developed a poor taste after processing.

''Less than a gram of rice was positioned in the injection port assembly of the gas chromatograph, and volatile analysis revealed that the product contained a strange compound that shouldn't be there. The extra element was identified by mass spectrometry as a fumigant used in storage,'' Dupuy said.

The injection port assembly allows the instant testing of a sample without sophisticated ''prepping'' of the sample first, he said. This testing can be done by nonscientists in environments that are less demanding than those of a strict laboratory. That makes Central Soya's commercial application of the process possible, says Dr. L. D. Williams, vice-president of research for the company.

''We sent our scientists to consult with Dr. Dupuy,'' he says. ''We then assembled the special equipment needed and tested it at the plant level. Today we still use the same gas-chromatography method devised by Dr. Dupuy, but we've automated it.''

The technique has reduced, but not totally replaced, the work done by panels of trained human taste testers, Mr. Williams says. It has added to their capabilities and ability to please customers.

Besides verifying flavor, the process can monitor the effects of processing conditions, evaluate the effects of storage, follow oil changes during shipment, monitor the the oil quality of finished products, and gauge the freshness and ''shelf life'' of a wide range of foods.

As for the competition, Mr. Williams says, ''We're pretty sure a couple of refineries are doing this in their labs. They know how to do it. But, as far as we know, we're the only ones making it available on a commercial basis.''

Mr. Flanagan says Central Soya welcomes the use of the technique by competitors so industry standards can be set and quality comparisons can become objective.