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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Food Quality Laboratory » Research » Publications at this Location » Publication #408985
Research Project: Integrated Approaches to Improve Fruit and Vegetable Nutritional Quality with Improved Phenolics Contents

Location: Food Quality Laboratory

Title: Effects of harvest day after first true leaf emergence of broccoli and radish microgreen yield and quality

Author
item Ortiz, Irma
item ZHU, XUDONG - Orise Fellow
item SHAKOOMAHALLY, SHIRIN - Orise Fellow
item WU, WENYI - Eleanor Roosevelt High School
item KUNLE-RABIU, OLAYANJU - Eleanor Roosevelt High School
item Turner, Ellen
item Yang, Tianbao

Submitted to: Technology in Horticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/26/2023
Publication Date: 2/2/2024
Citation: Ortiz, I.N., Zhu, X., Shakoomahally, S., Wu, W., Kunle-Rabiu, O., Turner, E.R., Yang, T. 2024. Effects of harvest day after first true leaf emergence of broccoli and radish microgreens. Technology in Horticulture. 4. Article e003. https://doi.org/10.48130/tihort-0023-0031 .
DOI: https://doi.org/10.48130/tihort-0023-0031

Interpretive Summary: Microgreens are 10-20-day old vegetables with high nutritional content. Commercially, producers tend to harvest microgreens at different times, after the first true leaf emerges. To determine the optimal harvest time, the microgreen yield and quality of two Brassicaceae vegetables, broccoli (Brassica oleracea L.) and radish (Raphanus sativus), were studied. Plants were grown in hydroponic conditions in a controlled growth chamber at 25 oC under a 16/8h photoperiod. The first true leaf of broccoli and radish emerged in average on day 11 and day 8 respectively. The microgreens were harvested at days 11, 12, 13 and 14 for broccoli or days 8, 9, 10, and 11 for radish. Broccoli harvested on day 13 days and radish harvested on day10, when about 75% of plants had first true leaf emergence, showed significantly highest yield and chlorophyll content compared to that in plants harvested at any other days. The overall visual quality of stored microgreens at 4 oC was also evaluated, in particular assessing the incidence/severity of decay. There was less visible decay for broccoli harvested at day 13 and radish harvested at day 10. In addition, there was a significant decrease in anthocyanins for radish harvested at day 11. The lowest glucosinolate content in broccoli was found on day 12. Overall, the results suggest that the best harvest time for radish and broccoli microgreens is when about 75% true leaf is emerging. This research provides results that can be helpful to microgreen growers for determining the optimal harvest time of microgreens.

Technical Abstract: Microgreens are 10-20-day old young vegetables with rich nutrition. In commercial settings, their harvest time varies after first true leaf emerges. To determine the optimal harvest time, the microgreen yield and quality of two Brassicaceae vegetables, broccoli (Brassica oleracea L.) and radish (Raphanus sativus), were analyzed after different harvest times. Plants were grown in hydroponic conditions in a controlled growth chamber at 25 oC under a 16/8h photoperiod regime. The first true leaf of broccoli and radish emerged on day 11 and day 8 respectively. Then the microgreens were harvested at days 11, 12, 13 and 14 for broccoli or days 8, 9, 10, and 11 for radish, to determine the effect of harvest time on microgreens yield, decay, and nutrient quality. Broccoli harvested at day 13 and radish harvested at day 10 day, when about 75% of plants had their first true leaf emergence, showed significantly highest yield and chlorophyll content compared to that of plants harvested at any other day. The plant yield was 20% higher when radish and broccoli were harvested at day 10 and day 13 compared to those harvested on earlier days. The overall visual quality of microgreens stored at 4 oC was evaluated for the extent of decay. There was less visible decay for broccoli harvested at day 13 and radish harvested at day 10. Regarding nutrient quality, there was a significant decrease in anthocyanins for radish harvested at day 11. The lowest glucosinolate content in broccoli was at day 12. Overall, the results suggest that the best harvest time for radish and broccoli microgreens is when about 75% true leaves emerge. This research will provide microgreen growers a basis for determining the optimal harvest time of microgreens.