Introduction to Microgreens

In response to evolving health trends and the prevalent adoption of the nutritionally deficient Western diet, a global deficiency in essential vitamins and minerals has emerged. Coupled with the increasing global population and climate change-induced declines in traditional agricultural productivity, there is a pressing need for novel functional foods characterized by rapid growth cycles, drought resistance, and compatibility with urban farming techniques such as vertical farming, hydroponics, greenhouses, and aquaponics.

Microgreens represent a convergence of medical, nutritional, and biological innovation, standing out as an exceptional functional food. These young seedlings of edible vegetables and herbs, harvested before developing cotyledonary leaves, possess nutrient densities up to forty times greater than their mature counterparts. With their demonstrated health and beauty benefits, cultivation adaptability, resilience, and positive environmental impacts, microgreens are gaining recognition as a potential staple of future diets.

The Development of Microgreens

Although the term ‘microgreens’ is relatively recent, the consumption of young, unripe vegetables has been practiced for decades. Some historians trace the modern microgreens movement back to chefs’ gardens in the 1980s in the United States, where young vegetables were cultivated, shipped, and consumed in their nascent stages. This trend gained further momentum as health-conscious eateries marketed microgreens as more nutritious than their mature versions.

Despite their existence predating the coining of “functional foods” in 2000, a standardized definition of microgreens and the plant species they encompass remains ambiguous. Synthesizing various studies, microgreens can be described as seedlings that have fully developed true leaves and non-senescent cotyledons but are harvested before root development.

Mass Production of Microgreens

Microgreens offer unparalleled cultivation versatility compared to their mature counterparts. Typically grown in controlled greenhouse environments, they can thrive in any setting with stable temperatures below 20°C and consistent humidity. Microgreens require significantly less labor and space than traditional crops; for instance, three to four individuals can produce over 90 kg of microgreens weekly within a 400 m² area. Fast-growing varieties can be harvested in just 10 to 14 days.

Effective pest management and humidity control are crucial for optimizing microgreen yields. Although susceptible to the same pests and pathogens as mature plants, their rapid growth and intrinsic bioactive compounds mitigate these challenges. Biopesticides and bacterial treatments have proven effective in preventing losses, and recent advancements in automated humidity regulation and harvesting have further enhanced yields in commercial operations.

Nutritional Superiority of Microgreens

Research has demonstrated that dormant dry seeds undergo significant biochemical and nutritional transformations upon germination, resulting in a concentration of nutrients within the edible parts of the plant. Consequently, microgreens boast a remarkably high nutrient content.

Comparative studies between germinating seeds, non-germinating seeds, and mature plants reveal that the primary and secondary metabolite profiles of germinating seeds differ significantly from those of the other two groups. As a result, some microgreen varieties contain nutrients not found in adult plants.

Health Benefits of Microgreens

Microgreens are rich in carbohydrates, proteins, lipids, vitamins, minerals, and phytochemicals. Clinical trials have highlighted their significant antioxidant potential and their medical benefits in reducing blood glucose levels, aiding weight management, and lowering cardiovascular disease risk. The phytochemicals in microgreens are easily digestible and are believed to possess antibacterial, anti-diabetic, and anti-inflammatory properties.

Notably, microgreens from broccoli, radish, and other Brassicaceae family members contain indoles and flavonoids with proven anti-cancer properties, particularly against colorectal cancer. Further research is needed to determine whether these benefits extend to other types of cancer and other microgreen species.

Challenges in Microgreen Production

The primary challenge facing the microgreen industry is storage; these plants have a very short shelf life, with rapid nutritional degradation during storage. Another significant challenge is the initial investment required for commercial production, which demands costly and specialized substrates, seeds, machinery, and labor.

Future Prospects

Looking ahead, well-designed clinical trials are essential to fully understand the health impacts of microgreens and to provide robust evidence of their health benefits. As research into microgreens continues, their promising attributes position them as a valuable focus for future advancements in preventive and therapeutic medicine.