Optimize fresh produce nutrition content.

Vegetables contain several nutrients that help prevent such diseases as cancer, diabetes, heart and immuno-deficiency diseases. Ensuring that these nutrients are still available to consumers by the time the vegetables are purchased is the motivation behind research underway in New Zealand. There, scientists with Crop & Food Research want to guarantee that fresh fruit and vegetables deliver optimum health benefits after they are harvested.

The investigators are working to enhance selenium levels in crops, particularly seleno-methyl selenocysteine, which is linked with cancer prevention. Nearly all selenium compounds contribute to the body's nutritional needs for selenium and its defense against cancer. Various selenium compounds have been shown to inhibit cancer in various organs, including the liver, skin, pancreas, colon and mammary gland. Several epidemiological studies show that people with higher levels of selenium compounds in their blood have less incidence of cancer than those with lower selenium levels.

Seleno-methyl selenocysteine is produced naturally in broccoli and other brassica plants, but not in many other horticultural crops. The scientists already have an understanding of the biochemical pathway for its production and are exploring its genetic control in broccoli and non-brassica crops.

Another area of research involves examining nutrient retention in crops that have had their postharvest storage life extended by scientists who have controlled the temperature, humidity and atmosphere of their environment, or who have manipulated their senescence-related genes or hormone content.

Vitamin C is an interesting research target because its loss in vegetables after they are harvested almost mirrors the vegetables' water loss. Yet the processes that control these losses are quite separate. Investigators want to understand the molecular connection between the two processes.

Investigations focusing on vitamin C in vegetables are significant. People who take daily doses of vitamin C can boost their immune system, potentially protecting themselves from viruses and colds. Vitamin C plays an essential role in the immune system. It aids in fighting off foreign invaders. It is vital to the production of collagen, which is involved in the building and health of cartilage, joints, skin and blood vessels. It helps protect the fat-soluble vitamins A and E as well as fatty acids from oxidation. It aids in neutralizing pollutants. It is needed for antibody production. It has natural antihistamine properties.

Further information. Julian Heyes, Crop & Food Research, P.O. Box 8031, Palmerston North, New Zealand; phone: + 64 6 356 8300; fax: + 64 6 356 1687 email: [e-mail].