Location: Food Quality LaboratoryTitle: Effect of preharvest CaCl2 spray and postharvest UV-B radiation on storage quality of broccoli microgreens, a richer source of glucosinolates
|LU, YINGJIAN - University Of Maryland|
|DONG, WEN - University Of Tennessee|
|Luo, Yaguang - Sunny|
|WANG, QIN - University Of Maryland|
Submitted to: Journal of Food Composition and Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/29/2017
Publication Date: 12/29/2017
Citation: Lu, Y., Dong, W., Yang, T., Luo, Y., Wang, Q., Chen, P. 2017. Effect of preharvest CaCl2 spray and postharvest UV-B radiation on storage quality of broccoli microgreens, a richer source of glucosinolates. Journal of Food Composition and Analysis. 67(1):55-62. https://doi.org/10.1016/j.jfca.2017.12.035.
Interpretive Summary: Glucosinolates (GLS) namely, glucoraphanin (GLR) and glucoerucin (GLE), are a class of plant compounds that are beneficial to human health. Broccoli flower buds (florets) have been known to be rich in GLS. Recently consumption of broccoli microgreens (sprouts) has increased along with consumer awareness and appreciation for their diverse flavors and beautiful colors. However, it is not clear whether broccoli microgreens contains high GLS. The present study compared the composition of GLS in broccoli florets, mature leaves and microgreens. These tissues varied in their GLR, GLE and total GLS contents. We found that GLE was present mainly in broccoli microgreens while GLR was found mainly in mature leaves and broccoli florets. Microgreens contained four-fold greater total GLS content than mature broccoli. Total GLS levels were increased by calcium spray treatment, while UV-B radiation showed minor effect. However, combined calcium and UV-B treatment increased GLS content greater than either treatment alone in broccoli microgreens. Calcium spray also enhanced visual quality and storage life of microgreens. These results are useful for microgreen producers in producing high quality microgreens with enhanced nutritive value.
Technical Abstract: Glucosinolates (GLS) namely, glucoraphanin (GLR) and glucoerucin (GLE), are a class of phytonutrients which are beneficial to human health. Broccoli flower buds (florets) have been known to be rich in GLS. The present study indicated that the florets, mature leaves and microgreen of broccoli varied in their GLR, GLE and total aliphatic GLS contents. GLE is the unique glucosinolate in broccoli microgreens while GLR is primarily condensed in broccoli florets and mature leaves. Microgreens contained four-fold greater total aliphatic GLS content than mature broccoli leaves and florets. In addition, the effects of preharvest CaCl2 and postharvest UV-B applications on the levels of GLR and GLE were investigated. Total aliphatic GLS levels increased significantly after 10 mM CaCl2 treatment, while postharvest UV-B radiation had minor additive effect. Furthermore, preharvest calcium spray showed improved overall visual quality and longer storage life. Hence, the CaCl2 application is the major factor to increase GLS levels and postharvest quality. These results indicated that broccoli microgreens is a better source of GLS intake than florets, and preharvest CaCl2 and postharvest UV have positive influence on maintaining the health-beneficial compounds and extending the shelf life of broccoli microgreens.