In 1999, Greenvale stumbled across an idea and began to test the storage of bananas with potatoes in sealed bags.
The project showed very good anti-sprouting results and in 2003, a dedicated business, The Restrain Company Ltd was launched. Today, the business leases ethylene generators across the world. The generators maintain a stable atmosphere of ethylene within potato and onion stores for sprout suppression. The technology is also being used in greenhouses for tomato ripening.
The treatment is continuous until the final potatoes leave the store.
Using the Restrain generator and sensor, a very low ethylene gas concentration is delivered. The dynamic ethylene gas, is about the same weight as air and evenly spreads to all stored potatoes in either bulk or wooden bins. The generated low ethylene concentration is automatically monitored in the store. During the storage time the ethylene production by the Restrain generator stops when it reaches a maximum level, and produces ethylene again once the minimum level is detected.
Along with potatoes, the concept of anti sprouting onions is based on maintaining certain levels of natural ethylene gas during storage which will evenly spread through onion stores.
Onions require 3 days ethylene exposure before the sprouts will be blocked. If the onions have already sprouted the ethylene gas will block further cell elongation.
The Restrain generator allows growers to harvest naturally ripened tomatoes at the end of the growing season direct from the plant.
Ripening tomatoes at the end of the season is often problematic. Strict residue legislation challenges the ability to produce full yields. With Restrain zero residue treatment growers can safely accelerate the ripening process on the plant using the natural ethylene gas.