But with increasing demand to reduce the use of plastic in the food chain, new technologies are emerging to keep food fresher for longer. One of these is the edible coating of fruits and vegetables, which are covered with a film of protective material that can be consumed with food. In the UK, this artificial coating is already used on apples, oranges, lemons and other fruits to help conserve moisture and extend shelf life.
Researchers are also experimenting with different substances, such as the protein secreted by the silkworm, chitosan (a sugar compound from the outer skeleton of shellfish), cashew gum, fish gelatin and cellulose and algae derivatives. The function of all of them is to form a thin membrane on the surface of the food. This reduces gas and water vapor transfer, which limits browning and loss of aroma and extends shelf life.
A recent study, covered strawberries with chitosan and an isolated substance of whey protein and, with that, increased the shelf life of the fruit by 60%, kept in the fridge. Tomatoes coated with chitosan and green algae remained nearly perfect even a month after picking.