The gel, which does not appear to affect food taste or appearance, shows promise as a safe, natural and environmentally-friendly alternative to conventional synthetic preservatives that are currently applied to produce after harvesting, the researchers say.
Although a number of edible coatings have been developed to preserve food freshness, the new coating is believed to be the first to use Aloe vera, according to study leader Daniel Valero, Ph.D., of the University of Miguel Hernández in Alicante, Spain.
Valero and his associates dipped a group of common table grapes (Crimson Seedless) into Aloe vera gel and stored them for five weeks under low temperature while exposing a group of untreated table grapes to the same conditions. The colourless Aloe gel used in this study was developed through a special processing technique that maximised the amount of active compounds in the gel, Valero and associates say. The gel can also be applied as a spray, they add.
The untreated grapes appeared to deteriorate rapidly within about seven days, whereas the gel-coated grapes were well-preserved for up to 35 days under the same experimental conditions, the researchers say. The gel-treated grapes were firmer, had less weight loss and less colour change than the untreated grapes, measures which correspond to higher freshness, they say.
A sensory panel (ten people) evaluated the quality of both the untreated and the gel-treated grapes by consuming some of the grapes. They found that the gel-treated grapes were generally superior in taste.
The researchers believe that the gel works through a combination of mechanisms. Composed mostly of polysaccharides, the gel appears to act as a natural barrier to moisture and oxygen, which can speed food deterioration.
The gel also offers potential environmental benefits, the researchers add. It could provide a greener alternative to sulfur dioxide and other synthetic food preservatives that are commonly used on produce and increasingly the target of health concerns, they say.
MEDICA.de; Source: American Chemical Society