2019 ASHS Annual Conference

Microgreens are seedlings of edible plants harvested 7 to 14 days after germination at the emergence of the first true leaves. In recent years, microgreen industry is emerging as an important part of urban farming. This presentation reports studies that comprehensively evaluated microgreen phytonutrient and technologies to improve microgreen production yield. Microgreens of selected species of Brassica family were grown, harvested, and tested for their nutritional values, along with their more mature counter parts. The effects of physical treatment (UVB) and plant growth regulators such as CaCl₂ on broccoli microgreen yield and levels of phytonutrients were also evaluated. Results demonstrate that microgreens contain abundance of various antioxidant compounds, with the exact concentration dependent on the plant species. In general, carotenoids, tocopherols, phylloquinone, and total phenolic compounds were high at younger growth stages (microgreens and baby greens). However, higher total ascorbic acid contents were found in mature red cabbage (91.8 mg/100g FW) and mature broccoli (118.8 mg/100g FW) than in their younger counterparts, respectively. Broccoli microgreens had four-fold greater total glucosinolates than mature broccoli leaves and florets.. Preharvest application of CaCl₂ and UVB boosted microgreen yield by 50% and improved overall visual quality and shelf life. These treatments significantly increased the content of total glucosinolates by around 70%. Thus microgreens have the great potential to be an important dietary source of phytochemicals for urban farming.