Electronic Sweetness Meter

From Omni Continuum, issue unknown

Consumers soon may find sweetness labels on the onions in supermarkets.

Scientists with the U.S. Department of Agriculture (USDA) have developed a light meter that can, 'read' the sweetness of onions and possibly of other fruits and vegetables.

'We found that by using near-infrared light and special filters we could measure the dry matter in onions, which is related to their sweetness,' says chemist Gerald D. Dull of the USDA's Agricultural Research Service. Dull and engineer Gerald S. Birth have been working together at the agency's Russell Research Center in Atlanta since 1973. Their goal is to rely on an instrument rather than taste and sight, to analyze fruits.

A silver-colored aluminum box about a foot long and two-feet deep, the onion meter works because the skin of an onion is translucent; in fact, about 1 percent of light directed at an onion passes right through it. In the box, devices on either side of the onion measure the amount of light transmitted. Once collected, this information is fed into a computer that analyzes the onion.

Dull believes the same technique can be adapted to test other fruits and vegetables as well. 'A portable meter in a supermarket could analyze fruits and vegetables to find out what carbohydrates and nutrients they contain,' says Dull. 'It would be like the labels on canned and frozen foods.'

The onion meter is available through the Varex Corporation in Rockville, Maryland. So far its primary users have been onion growers and breeders, who use it to select quality onions for replanting. 'Previous selection methods involved boring out a section of the onion,' explains Dull. This is destructive and slow, while the light meter can sample an onion a second.

What's next? Dulla and Birth have developed a meter that measures the sweetness of papayas based on the amount of the pigment carotene they contain. They hope to expand present technology so that they can measure the sugar in cantaloupes, melons and even potatoes. - Lisa Werner

Low-Tech Handheld Device Detects Counterfeit Drugs

ATLANTA -- Scientists at the Centers for Disease Control and Prevention (CDC) have adaped a simple low-tech device normally used to examine urine specimens to test and detect counterfeit drugs. They report their results on a method to test malaria drugs today at the 50th Annual Meeting of the American Society of Tropical Medicine and Hygiene in Atlanta.

"Counterfeit malaria drugs are a widespread problem in many parts of the world, especially in southeast Asia ," says Michael D. Green, a chemist in the CDC Division of Parasitic Diseases and the presenting author of the study. "A survey in southeast Asia determined that 38% of samples of the malaria drug artesunate purchased at retail outlets contained no active ingredients whatsoever." In 1999 at least 30 malaria deaths in Cambodia could be linked to inadequate treatment due to counterfeit drugs

. The device, called a handheld refractometer, has been commonly used by clinics to measure the specific gravity of urine specimens. Green and his colleagues realized that by measuring the specific gravity of certain dissolved drugs, one could easily determine the amount of active ingredient in a tablet. While not able to conclusively identify an unknown drug, the device could be used as a first line of defense to identify counterfeits.

The test is simple and the refractometer is relatively inexpensive with adequate devices costing less than $100. The tester simply takes a sample of the medication (usually a tablet), pulverizes it, dissolves it in alcohol and filters out any solids left. A drop of the clear solution is placed on the refractometer, which casts a shadow line giving the refractive index. That index can be converted to specific gravity, which is compared to a standard already established for that particular drug.

"This is a simple, relatively low-tech approach that people in developing countries who have limited resources can use," says Green. So far, Green and his colleagues have only tested this approach in the lab. He hopes to begin field testing soon. While this study focused only on malaria drugs, the refractometer can be used to detect all sorts of fake drugs. Green has also studied several tuberculosis drugs and hopes to expand this application to other drugs.

"This application could be used to test mass batches of drugs imported from overseas. It could also be used to screen drugs sold outside the formal U.S. pharmacy system, such as over the internet, where counterfeits could be easily pushed on the consumer," says Green.