Sauté radish microgreens for an addition to stir-fries and other hearty dishes. Even when exposed to varying hot air drying temperatures, they show excellent resilience in nutrient retention. According to a December 2021 study led by Marjorie J. Jauregui and team leader Joshua Lambert, that’s an effective way to keep the microgreen nutritional profile intact. If they are dried at low temperatures, like 203°F, their phenolic can be preserved. Published in the Journal of Food Science, the study explores the effects of different drying methods on the nutritional stability of radish microgreens.
The research found that radish microgreens retained 91% of their total phenolic content when dried at 113°F and 79% when dried at 149°F. Remarkably, drying at 203°F resulted in total phenolic content retention. These findings suggest that hot air drying may be a promising option. It is a convenient approach for maintaining the health promoting properties of cruciferous vegetables.
Nutritional Stability Across Drying Temperatures
One such study investigated the impact of drying temperature on not only phenolic content, but individual vitamins and phytochemicals. Vitamins B1 and B9 were shown to be stable at every tested temperature. This is important so that these beneficial nutrients remain preserved regardless of the drying conditions.
Additionally, vitamin B2 had significantly higher bioaccessibility when radish microgreens were dried at 149°F versus lower or higher drying temperatures. The study produced some interesting results related to bioaccessibility. The total phenolic content and the vitamins B1, B3, B9, and C were 13-68%, with no significant differences between all the drying processes carried out.
“Hot air drying is more practical, especially in low-resource areas, but we need to fully understand how different drying temperatures affect key nutrients and phytochemicals—plant compounds that provide health benefits. These results are more than a good start.” – Joshua Lambert
Health Benefits and Practical Applications
Radish microgreens have become well known for their high concentration of compounds that promote cardiovascular and immune health. The current study reinforces that hot air drying is a good technique for the conservation of health-promoting attributes. This technique is highly beneficial when developing powdered forms of microgreens to be incorporated into other food products.
Even though some nutrient loss is likely during the drying process, key components such as glucoraphenin stayed consistent at both 113°F and 149°F. Yet, at 203°F, glucoraphenin retention fell to 78%. As a result, the research found a compelling anomaly. Although glucoraphenin and anthocyanins underwent degradation or degradation to unmeasurable amounts after digestion, other nutrients had stability.
“While some nutrients are lost, others remain stable and, overall, hot air drying is a practical and promising postharvest method.” – Marjorie Jauregui
These insights come at a time when microgreens are experiencing increased popularity, thanks in part to their recognized nutritional density. They have a short shelf life. Usually lasting just one to two days at room temperature, they are capable of remaining fresh for a maximum of 14 days in a cool environment, such as a fridge.
Implications for Future Research
Jauregui and Lambert’s study provides some key insights regarding drying methods. These findings represent a novel opportunity to investigate methods of retaining nutritional quality in microgreens. Lambert acknowledged that freeze-drying works well, but it isn’t a new technology that’s readily available, as it needs pricey equipment, which wouldn’t be able to all environments.
“Freeze-dried microgreens require expensive, specialized equipment to produce,” – Joshua Lambert
How different drying methods impact nutrient holding Researchers are still desperately trying to figure out how various drying methods impact nutrient retention. At the same time, radish microgreens hold incredible potential for use in nutrition and health promotion.