Post-harvest Physiology of Microgreens
Microgreens are seven- to ten-day-old seedlings of various vegetable crops that are packaged as young shoots, including both cotyledons and hypocotyls. To improve the marketability of this highly perishable product, shelf life must be extended by controlling respiration rates. Little information is available describing the post-harvest characteristics of this high value specialty crop, and its respiration rates have not yet been carefully quantified. The present study aims to investigate the respiration rates and shelf life of microgreens. Three crop species were evaluated in this study: arugula (Eruca sativa), radish (Raphanus sativus), and red cabbage (Brassica oleracea var. rubra). Respiration rates (estimated by CO2 evolution) were measured at harvest and in storage for a total of three weeks using an infrared gas analyzer. Product quality was evaluated visually each week. Based on visual analysis, shelf life averaged fourteen days for arugula and red cabbage, and twenty-one days for radish when stored at 4°C. However, shelf life was reduced to seven days when stored at 10°C for red cabbage and arugula, while it was reduced to fourteen days for radish. Red cabbage and arugula had the highest respiration rate at harvest, which also corresponded to a decrease in visual quality. Beginning in week two there was a spike in respiration rates, possibly due to decay organisms, which also corresponded to a decrease in the visual quality rating of the crop. This study aims to provide a benchmark data set for future microgreens post-harvest experiments designed to lower respiration rates and increase shelf life. Increased shelf life for this specialty crop will allow for transportation to larger markets.