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Options for sourcing 1-methylcyclopropene for 2021


EAST LANSING, MI. — Apple fruit are ripening and headed to storage. How will our storage operators choose among the many options to supply their needs for the apple ripening inhibitor, 1-methylcyclopropene (1-MCP)?

The proliferation of sales options and variations in the formulations and technologies for delivery of 1-MCP has led to some confusion in the apple industry. The following is an update on delivery technologies used by various suppliers of 1-MCP, which has become an essential element of apple handling following the maturation and harvest of this important Michigan fruit. 

1-MCP history

Since its discovery by Ed Sisler and Sylvia Blankenship in 1996, the ethylene action inhibitor 1-MCP, a gas, has dramatically changed the way apple fruit are handled and stored. Typically, the 1-MCP is released into a sealed room being used for treatment and the exposure period is roughly 24 hours. The target concentration for the 1-MCP is one part per million. Following the entry of 1-MCP into the postharvest handling of apple fruit, the quality of fruit delivered to the consumer has undergone a phenomenal improvement in textural characteristics and condition. I cannot remember the last time I found decay in bagged apple fruit; this used to be a common occurrence prior to the introduction of 1-MCP.

There have been many changes in the market for 1-MCP too. Originally, the only purveyor of 1-MCP was Dow/Rohm and Haas/AgroFresh for food crops and FloraLife for non-edible plant products. The food-applied material, SmartFresh, was first commercially available from AgroFresh in 2002, registered first in Chile, then in the U.S. The SmartFresh technology was protected by a number of patents, but principal among them was a use patent that expired in 2015 and a formulation patent that expired in 2018. AgroFresh was sold in 2015 and renamed AgroFresh Solutions. The expiration of the patents has seen a proliferation of alternative suppliers of this technology, some of whom have already left the marketplace.

The following is a chronological portrayal of the various technologies and a little of what is known about the mode of delivery of the 1-MCP molecule.

SmartFresh (2002-present)

SmartFresh (3.3% active ingredient) is a formulation of 1-MCP that is encapsulated in a material known as alpha cyclodextrin. In this formulation, the 1-MCP is lodged in the center of a ring of linked sugar molecules that permits the handling of the gaseous 1-MCP as a powder. This formulation is extremely stable, although it has to be protected from water. Upon the addition of water, the cyclodextrin dissolves and the 1-MCP is liberated as a gas.

Powdered SmartFresh is contained in dissolvable pouches that are added to canisters holding a few gallons of water. After 5 minutes or so, the pouches dissolve and the water gains access to the SmartFresh and 1-MCP is liberated. The transfer of the 1-MCP molecule into the air of the treatment chamber is facilitated by air pumps that bubble air through the solution in which the SmartFresh is being dissolved, or, more recently, through the use of effervescent tablets.

1-MCP is usually applied in the room and the apparatus used to administer the gas is collected after the treatment is finished. The amount of 1-MCP is controlled by the size and number of sachets or tablets used. There are several additional 1-MCP technologies available from AgroFresh Solutions including Harvista, ProTabs, InBox and SmartTabs. SmartFresh tablets and water-dissolvable sachets are handled in a protective sealed foil pouch.

For inquiries, contact Mark Zemaitis of Sparta, Michigan, at 616-215-3558 or MZemaitis@agrofresh.com.

Fysium (2015 - present)

Fysium (100% active ingredient) is a version of 1-MCP from Pace International LLC that is supplied as a gas rather than as a powdered formulation. A module that contains the chemical precursors to the 1-MCP molecule is used to carry out a chemical reaction to generate the gas. The amount of 1-MCP is controlled by the amount of chemical reactants and the number of modules. These modules need to be recharged for reuse. Fysium is introduced from the exterior of the room, usually through a port in the door or wall, so it can be applied after the room is sealed, which is sometimes desirable to accommodate fruit handling needs.

For inquiries, contact Brian Zimmer, Pace International, of Seattle, Washington, at 509-654-0732 or bryan.zimmer@paceint.com. 

TruPick (2016 - 2017, no longer available)

TruPick (2% active ingredient) was a 1-MCP formulation developed by Essentivand marketed by Decco, but following a dispute with AgroFresh Solutions, became the property of the latter in 2017. TruPick used a material called a metal organic framework (MOF), which has the capacity to adsorb (i.e., cling very tightly) 1-MCP and other gases. Adsorbents like MOFs are crystalline powders and do not encapsulate the gas, but can temporarily hold onto the gas, often in very high quantities; in the case of 1-MCP, the holding capacity of the MOF was near 10%.

MOFs tend to be extremely sensitive to water and water vapor, such that exposure to high humidity can induce the release of the adsorbed 1-MCP. To protect the TruPick MOF from losing 1-MCP, the MOF particles were sealed in a water-soluble gel. Like SmartFresh, this allowed the material to be handled as a powder that released the 1-MCP upon dissolving in water. TruPick water-dissolvable sachets are handled in a protective sealed foil pouch.

Easyfresh (2018 - present)

Easyfresh (3.3% active ingredient) is a 1-MCP formulation from Fine Americas, Inc. Easyfresh is a cyclodextrin-based 1-MCP formulation, much like SmartFresh. Also like SmartFresh, it is handled in dissolvable pouches that require dissolution in water. Agitation of the water in the dispensing canister is a combination of air bubbler and submersible water pump that uses rechargeable batteries for reuse. Easyfresh is applied by local distributors of agricultural chemicals, but with training, has the potential for self-application. Self-application reduces the amount of coordination needed for treatment and improves flexibility at the level of the storage operation. Easyfresh water-dissolvable sachets are handled in a protective sealed foil pouch.

For inquiries, contact John Rasch of Sparta, Michigan, at 616-293-8815 or jrasch@wilburellis.com.

Hazel (2019 - present)

Hazel is a 1-MCP formulation developed by Hazel Technologies. It is an activated carbon sorbent, behaving much like the MOFs used for TruPick. Like all adsorbents, it will readily desorb the contained gas. To prevent this, Hazel is held under freezing temperatures in a hermetic pouch prior to use. Hazel CA (2% active ingredient) is fast-releasing version of the technology applied via a dispenser that uses a fan to run room air over the adsorbent. In this system, the hermetic pouch is opened and the chilled material is added to the canister.

In response to the higher humidity and higher temperature of the storage room, the 1-MCP escapes the adsorbent and the fan delivers the released gas to the room. The Hazel technology is also applied as a "time-release" sachet (Hazel 100, 3% active ingredient) that is placed on the top of each bin in a room (or, using a smaller sachet, in a box) without requiring room sealing. The sachet version is self-applied. Hazel adsorbents and sachets are handled in a protective sealed foil pouch.

For inquiries, contact Eli Cannell of Chicago, Illinois, at 559-515-1074 or eli@hazeltechnologies.com.

FirmConfirm (2020 - present)

FirmConfirm (3.3% active ingredient) is a 1-MCP formulation from MirTech, Inc. FirmConfirm is a cyclodextrin-based 1-MCP formulation, much like SmartFresh. Also like SmartFresh, it is handled in dissolvable pouches and requires dissolution in water. Agitation of the water in the dispensing canister is by a rotary paddle. FirmConfirm is intended to be self-applied; the storage operator or grower can apply FirmConfirm following a training session. FirmConfirm water-dissolvable sachets are handled in a protective sealed foil pouch.

For inquiries, contact Xi Chen of Belle Mead, New Jersey, at 732-853-2613 or chenxince4@gmail.com.

Summary

Provided the formulation of choice delivers on its ability to achieve the needed dosage of 1-MCP, the performance of the described formulations should be relatively similar. 1-MCP is, after all, 1-MCP. That being said, there may be situations where rapid (or slow) release for a particular fruit cultivar or application is most appropriate, so some attention needs to be given to achieving treatment targets. Each of the noted companies provides some form of treatment verification or success, so this goal should be readily achievable.

The future

Innovations relative to 1-MCP continue. Options we will likely see include additional opportunities for external applications to rooms, more self application, multiple applications throughout (and following) the storage campaign, sensors that can be integrated into monitoring systems to assess the success of application, and sensors to detect the applied 1-MCP wearing off. There may also be more players in the field, or fewer!

Certainly, there are numerous overseas manufacturers and sellers of 1-MCP, which suggest the former could be true. In any case, 1-MCP, in its many forms and formulations, will continue to provide an important quality protectant for apples in the years to come and it will be up to the individual storage operation to determine the best fit for their needs.