Preharvest UVB Application Increases Glucosinolate Contents and Enhances Postharvest Quality of Broccoli Microgreens.

Yingjian Lu,Tianbao Yang,Yaguang Luo,Pei Chen,Wen Dong

doi:10.3390/molecules26113247

Abstract

Broccoli microgreens have shown potential health benefits due to their high glucosinolate (GL) levels. Previously, we observed that postharvest UVB treatment did not have much effect on increasing GLs in broccoli microgreens. In this study, we investigated the influence of preharvest UVB irradiation on GL levels in broccoli microgreens. UHPLC-ESI/ITMS analysis showed that preharvest UVB treatments with UVB 0.09 and 0.27 Wh/m2 significantly increased the glucoraphanin (GLR), glucoerucin (GLE), and total aliphatic GL levels by 13.7 and 16.9%, respectively, in broccoli microgreens when measured on harvest day. The nutritional qualities of UVB-treated microgreens were stable during 21-day storage, with only small changes in their GL levels. Broccoli microgreens treated before harvest with UVB 0.27 Wh/m2 and 10 mM CaCl2 spray maintained their overall quality, and had the lowest tissue electrolyte leakage and off-odor values during the storage. Furthermore, preharvest UVB 0.27 Wh/m2 treatment significantly increased GL biosynthesis genes when evaluated before harvest, and reduced the expression level of myrosinase, a gene responsible for GL breakdown during postharvest storage. Overall, preharvest UVB treatment, together with calcium chloride spray, can increase and maintain health-beneficial compound levels such as GLs and prolong the postharvest quality of broccoli microgreens.

Highlights

IntroductionPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
These results indicate that preharvest calcium and UVB treatments stimulated GL accumulation in broccoli microgreens
MY expression levels correlated to the GL levels during storage (Table 1 and Figure 4). These results suggest that the reduction in GLs in broccoli microgreens during postharvest storage mainly resulted from MY catalyzed GL break8 of 10 down

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Consumption of microgreens has increased as a result of consumers’. Appreciation for their diverse flavors, beautiful colors, and highly nutritional value. Microgreens are seedlings of edible plants harvested around two weeks after germination at the emergence of the first true leaves [1]. Previous studies have shown that broccoli microgreens contain higher glucosinolate (GL) content than broccoli florets and mature leaves, indicating that microgreens are a richer source of GLs than mature broccoli [2]

Methods

Results

Conclusion