The problem of rotting apples and mouldering grain may have been a matter of season-to-season survival for our ancestors. Today preventing food waste is no less of a challenge, though the stakes have changed somewhat. The world’s greenhouse gas emissions from wasted food are about 10 times greater than those from the UK.
One potentially promising technology is edible coating: covering fruits and vegetables in a film of protective material that can be consumed with the food. Modern commercial coatings have come on a fair way since the early soy and lard experiments in Japan, England and elsewhere. Coatings based on beeswax or paraffin took off in 1930s, when waxing fruits such as apples became popular.
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While these are pretty good at limiting dehydration of produce, there is still great room for improvement. To create perfect edible coatings scientists are now experimenting with many different substances, from silk fibroin (protein secreted by silk worm) and chitosan (a sugar from the outer skeleton of shellfish), to cashew gum, fish gelatine, fenugreek protein, soy protein, cellulose and algae derivatives – the list goes on.
Such coatings, applied by dipping, brushing or spraying, form a thin membrane on the surface of, say, strawberries or tomatoes, reducing transfer of gas and water vapour, limiting browning and aroma loss, and ultimately prolonging shelf life.
