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Spray-On Edible Coating Might Replace Plastic Wrap
The problem of dealing with plastic wrap used on baled hay and silage might be a thing of the past, if a promising new spray-on edible coating proves reliable.
The focus of a field trial at the University of Guelph with 13 producers and a team of researchers is to test a spray made of natural biodegradable materials to provide a protective seal. The natural ingredient is zein, a powder protein byproduct of corn that is not commonly used in food, but is edible, water-insoluble and dries hard when combined with a follow-up spray with a salt or acetic acid. Zein has been used in many applications, such as coating for candy and fruit, encapsulating drugs and coating paper cups.
  “When you spray it, it clings like a spray-on Band-Aid,” says Environment Engineer Erica Pensini, who has been experimenting with adding zein to water, spraying it on hay or soil, then spraying it again with a solution containing fertilizer salts to solidify it. Working with Alexjandro Marangoni, a professor in the Food Science Department and graduate students, the goal is to find a formula that provides good protection and breaks down safely to work into the soil.
  Last summer, she sprayed it on soil to create an invisible mulch, with holes poked in it to place seeds or plants. Because the zein spray seal held moisture, the plants did better during drought times compared to plots that weren’t mulched. This summer, Pensini is working with a garlic grower using the same principle.
  But the biggest interest comes from dairy and beef producers interested in protecting silage and bales, so she will also be experimenting with them. Since the products are edible, cattle could eat the coating along with the feed. The problem is that rodents could also eat the coating, resulting in feed losses.
  To avoid that, researchers will be testing various formulas adding things like linseed oil hardened with oxidizers.
  The trial’s goals are to come up with a spray that stands up in all field conditions in low and high temperatures, and holds up when silage ferments and that can degrade safely back into the soil. Creating a flexible, durable bale wrap will likely be the biggest challenge, Pensini says.
  With zein easy to access and only simple mixing involved, a successful product would be easy to make. It likely won’t be cheaper than plastic. But for many farmers, avoiding the hassle of waste plastic is worth the cost of an environmentally-friendly product.
  There are many other potential applications. For example, Pensini melted zein, added linseed oil, and shaped plants for pots that are durable and attractive to consumers who are environmentally conscious.
  Contact: FARM SHOW Followup, Erica Pensini, University of Guelph, 50 Stone Rd. East, Guelph, Ont. N1G 2W1 Canada (ph 519 824-4120; epensini@uoguelph.ca).

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2021 - Volume #45, Issue #3