Silk protein as an edible food wrapper
Silklab at Tufts University has been using silk as a solution for various technological challenges. Scientists have transformed silk into useful materials, such as faux leather, optical sensors and coatings that can extend the shelf life of food.

The silk used in the lab is different from textile commodity silk, as it is melted into a liquid instead of. It can be turned into a variety of materials, including electronics, and it's bio-friendly and safe to eat or implant. One application of silk protein that has found its way into the market is as an edible coating to extend the shelf-life of food.

Basically, the surface of the fruit is moistened with a liquid silk formula. When it dries, it forms a very thin film that is transparent and tasteless. The silk coating controls the respiration of each fruit and acts as a protective barrier, keeping pathogens out while keeping moisture in. In a study published in 2016, they described how pieces of fruit, strawberries and bananas were coated with silk and left at room temperature. Compared to the uncoated fruit, the strawberries were still red and firm after a week, and the bananas did not turn black or overripe.

Hydrolysed silk and silk powder have long been used and consumed as a food additive in some parts of the world. The silk coating technology has been further developed by Mori. Silk coated spinach is now sold in major retail outlets in the Northeastern US.

Any silk can be used as a coating, and very little of it is needed to protect food, which makes it affordable. Unlike the textile industry, silkworms do not necessarily have to be killed to use their cocoons. In the future, with synthetic biology-based approaches, we may be able to produce the protein on a large scale using bacteria, plants or other carriers instead of extracting it from cocoons.The use of silk coating on food could lead to a wider reduction in food waste worldwide, which currently amounts to over a billion tonnes per year.


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