Spanish researchers have developed a gel from tropical plant aloe vera useful as an edible, invisible and tasteless coating, prolonging the quality of fruits and vegetables.

The University of Miguel Hernández, Alicante, Spain, study will appear in the American Chemical Society's Journal of Agricultural and Food Chemistry. The researchers claim the gel - based on a plant widely used in Spain by sunburned tourists - could be a safe and environmentally friendly alternative to synthetic preservatives.

They experimented on table grapes, using a gel processed to maximise active aloe compounds: untreated grapes deteriorated rapidly within seven days, while gel-coated grapes were well-preserved for up to 35 days.