Microgreens are edible seedlings harvested at the cotyledon stage or when the first true leaf forms. These delicate young greens are packed with nutrients and add a distinct flavor, texture, and color to a variety of dishes. Consumers and chefs alike appreciate their aesthetic appeal as much as their fresh taste and high nutritional content. However, given their fragile nature, microgreens have a relatively short shelf life, typically ranging from one to two weeks. Despite this, there are methods that can ensure their freshness lasts longer. Let’s delve into how you can achieve this.
Proper Harvesting
The longevity of microgreens begins at the harvesting stage. Using a sharp blade, cut the seedlings near the base but be cautious not to cut into the growing medium. Always harvest the microgreens when the growing area is dry to prevent the spread of disease or mold.
Immediate Cooling
Following harvesting, an immediate cooling process known as hydrocooling can greatly extend the shelf life of microgreens. This involves placing the greens in chilled water (0-5°C). The swift reduction in temperature is effective in reducing the rate at which the microgreens respire, thereby prolonging their freshness.
Maintaining Hydration
While it’s important to keep microgreens dry during harvesting, hydration post-harvest plays a crucial role in extending their shelf life. Pack the microgreens so that they retain their moisture without soaking in water. Use a perforated plastic bag that allows airflow but retains enough moisture to keep the greens hydrically balanced.
Packing And Storing
Pack microgreens loosely to prevent them from being crushed. Using hard, vented clamshells or clamshell tray’s can be helpful for protecting the tender microgreens from damage. In terms of storage, the optimal conditions are a low temperature (1-2°C) and a high relative humidity (90-95%). These will reduce the rate of respiration and transpiration, and consequently slow down the aging process.
Modified Atmosphere Packaging (MAP)
This is an innovative way to extend the shelf life of microgreens. MAP involves the regulation of oxygen, carbon dioxide, and nitrogen within the packaging in a way that retards the growth of harmful organisms and slows down the product aging process. When combined with refrigerated storage, MAP significantly lengthens the shelf life of microgreens.
Regular Quality Checks
Performing regular quality checks while they are stored is integral for maintaining the freshness of microgreens. Make sure to discard any that have turned yellow or have foul odors as they can spoil the rest in the pack.
Handling During Delivery
Proper handling of microgreens during delivery is essential. Use a refrigerated vehicle to maintain optimal temperature. Toss and shake the boxes gently so the microgreens are not packed tightly together.
Active Packaging Technologies
The use of active packaging technologies can also assist in prolonging the shelf life of microgreens. Examples include antimicrobial packaging, which releases antimicrobial substances to kill or inhibit the growth of microbes or nanotechnology-based containers that incorporate natural plant extracts to slow down the degradation process.
Use Of Plant Growth Regulators (PGRs)
Some studies suggest the use of post-harvest sprays with plant growth regulators (PGRs), like gibberellic acid, can extend the shelf life of microgreens.
Education and Training
Lastly, training those handling microgreens about the sensitivity of the product reinforces proper handling, cooling, and storage practices, thereby contributing to longer shelf life.
The exact duration of microgreens’ freshness depends on several factors. However, with education, technology, proper handling, and storage techniques, the shelf life of these nutritious greens can be greatly extended. Remember, preserving the shelf life of microgreens isn’t just about maintaining their visual appeal. It’s also about preserving their nutritional content and ensuring they retain their distinct flavor, appealing texture, and vibrant colors. By following these steps, both growers and consumers can enjoy high-quality, long-lasting microgreens.
