Small and mighty: microgreens

In addition to their intense flavour, vivid colour and high nutritional values, microgreens are considered to be “functional foods,” which are known to have disease-preventing and health-improving properties. Dr Kevin Robinson visited 2BFresh in Israel to find out more

According to the USDA-ARS Food Quality Laboratory in Baltimore (MD, USA), microgreens is a marketing term used to describe tiny, tender, edible greens that germinate in soil or a soil-less substrate from the seeds of vegetables and herbs.

Smaller than “baby greens” and different in nature from “sprouts,” microgreens can provide a variety of flavours and aromas that are similar to their mature plant counterparts … only more intense — from sweet and spicy to sour and salty and much more. They are also known for their various colours and textures. Among upscale markets, they are now considered to be a specialty genre of greens that are good for garnishing salads, soups, plates and sandwiches.

According to 2BFresh, however, a subsidiary of Teshuva Agricultural Projects Ltd (TAP), their microgreens — smaller and more tender, yet more robust and flavourful than sprouts — offer sustainability, food safety, freshness, convenience and value for money.

2BFresh produces agricultural products using advanced methods and provides consulting services for companies wishing to establish new agricultural ventures.

Advanced methods result in fresh herbs and lettuces being grown in a variety of different soil-less cultures, such as coco-peat grow bags and a hydroponic nutrient film technique (NFT) whereby a shallow stream of water containing nutrients is recirculated past the exposed roots of plants in a watertight gully, all inside a climate-controlled, insect-protected greenhouse. This unique growing method leaves the plants free from insects, sand, pesticides, etc., and also uses less water and less labour than conventional techniques.

“Our production, post-harvest and logistics methods are environmentally friendly,” noted Shay Zeltzer, Senior VP, as I toured the impressive facility in Olesh, Israel. “All the water is recycled and there’s no wastewater to pollute the ground,” he added. In addition, even in the accelerated growth environment of the company’s greenhouses, there’s no etiolation and the plants are ready for harvest in just 7–21 days (variety and season dependent).

Traditionally, microgreens are germinated in a pot containing a growth substrate and subsequently delivered intact. 2BFresh has developed the expertise and protocols so that instead of having to cut the plants prior to service, they’re available in a pre-cut and packaged format.

“This makes them more compact,” adds Shay, “so the shipping volume is much lower than that of living microgreens. We can provide ten times more plant matter per volume shipped, they’re more convenient and easy to use, and the packaging itself is recyclable, which means less waste. All of that with uncompromised freshness and shelf-life.”

Microgreens are usually harvested when they’re 2–3 inches tall and, depending on the species, are sold with the stem attached to the cotyledons. When analysed by USDA for essential vitamin and carotenoid content, researchers found that among the 25 species tested, red cabbage, cilantro, garnet amaranth and green daikon radish had the highest concentrations of vitamin C, carotenoids, vitamin K and vitamin E, respectively.

In general, microgreens contained considerably higher levels of vitamins and carotenoids — about five times greater — than their mature plant counterparts.

“Our products are not only highly nutritious, they’re also clean and ready to use,” says Shay. Once only available for chefs in professional kitchens, 2BFresh is also targeting the home and retail markets. With 20–30% of its output sold in Israel, the company's portfolio includes the following:

Basil Neto: Described as “nothing but edible product,” Neto translates as more leaves, fewer stems, which means that customers aren’t paying for the parts of the plant that get cut off and discarded. Instead of a bunch of basil providing 20% useful material, Neto delivers 100% in a reusable and recyclable container. Harvested in a unique serving size — larger than microleaves, yet much smaller than the mature herb, this basil is highly fragrant and rich in colour.

Pearl Herbs: For picky chefs and high end restaurants, these are hand-picked “elite” herbs with increased flavour and texture — small, very aesthetic prime leaves. These exquisite “pearls” have a long shelf-life, a rich flavour and crispiness that makes them ideal for garnishing gourmet dishes. The kit contains five punnets and buyers can choose from a list of Pearl-approved products.

Chef’s Kit: “Green, clean and perfect,” a selection of ready-to-use herbs for domestic use. Described as a presentable assortment of seven microgreens, specially packed in a handy kit, a selection can be made from the following list: sakura, pea shoots, mustard green/red, rocket, red chard (green bull's blood), pak choi (green/red), mizuna (green/red), kale and broccoli.

“They’re not just for chefs and they’re more than a garnish,” enthuses Shay. And with the company exporting its microleaves and products to the UK, Germany, France, Poland, the Czech Republic, Russia, Switzerland, Hong Kong and the USA, there’s clearly a growing market.

“We’ve developed pre- and post-harvest best practices,” comments Shay, “such as drying and precooling. We’ve also invested a lot of time and effort in cold chain management to ensure that our greens arrive in the best state of freshness. Each batch generates a shipment arrival report, which lists every stage of its journey, from the packing facility to the airport to the customer, providing full date, time and temperature information.”

In addition, 2BFresh products have a much longer shelf-life than regular fresh herbs; 90% of the microgreens stay fresh for more than 10 days and some can remain edible for more than 2 weeks.

Health benefits

The consumption of cruciferous vegetables has long been associated with several health benefits, including cancer prevention. Many of these benefits are attributed to the isothiocyanate phytochemical, sulforaphane (SFN), which is derived from cruciferous vegetables such as broccoli and broccoli sprouts.

These vegetables contain glucoraphanin (GFN), SFN’s precursor, which is converted to SFN by the plant enzyme, myrosinase. Studies have shown that SFN influences a variety of biological pathways that are thought to be critical for maintaining health and preventing disease. For example, SFN has been shown to reduce inflammation and oxidative stress, and promote cancer cell-specific cell cycle arrest and apoptosis, leaving healthy cells intact.

Although there has been intense study of the molecular and genetic targets of SFN, there is still limited knowledge regarding the biological pathways it targets in humans. A recent study was done to identify examine certain metabolomic profiles in healthy adults before and after consuming fresh broccoli sprouts, a rich and bioavailable dietary source of SFN, to observe how multiple metabolites respond to SFN consumption in vivo.

Twenty healthy adults consumed 200µmol of SFN equivalents from fresh broccoli sprouts and provided blood samples at time 0, 3, 6, 12, 24 and 48 hours following consumption. Untargeted metabolomic analysis was done on plasma samples from each time point using an AB Sciex TripleTOF 5600 coupled to a Shimadzu ultra-high performance liquid chromatography system.

Following sprout intake, altered levels for metabolites associated with steroid, lipid and protein metabolism, the urea cycle, nucleotide and one-carbon metabolism, and glutathione synthesis were observed, providing important information on novel molecular targets and mechanisms of SFN that may help to improve the understanding of SFN’s role in health and disease prevention.

Granted, the research was done using sprouts as opposed to microgreens, and it’s recognised that growing, harvesting and handling conditions may have a considerable effect on nutrient content, but studies on individual plant species that are grown and harvested as microgreens are currently helping to fill the dearth of available information in this budding industry, which will ultimately assist growers, grocers, chefs and, ultimately, consumers.