Selenium-Sulfur Coupled Heat Treatment: A Strategy for Producing High-Quality Broccoli Sprouts

Broccoli sprouts are abundant in bioactive antioxidants and are recognized as a novel class of functional food. This study explored the mechanisms by which selenium-sulfur coupled with heat treatment (HSS) affects the antioxidant capacity and accumulation of bioactive compounds in broccoli microgreens. The results showed that, compared to the control group, 4-day-old broccoli sprouts treated with HSS exhibited a 27.16% increase in total phenolic content and a 26.63% increase in anthocyanin content. Activities of catalase, superoxide dismutase, and peroxidase increased by 27.97, 30.54, and 46.48%, respectively. These changes enhance the antioxidant capacity of broccoli sprouts. HSS induced the biosynthesis of glucosinolates (GLs) and isothiocyanates (ITCs) by increasing myrosinase activity in the sprouts and upregulating the expression levels of genes associated with the GLs and ITCs biosynthetic pathways. iTRAQ proteomics analysis further revealed that the GLs biosynthetic pathway is the key pathway for ITCs accumulation induced by combined selenium-thiocyanate and heat stress. In addition, MAM1, APS3, SULTR1;2, and CYP79B3 were identified as potential key proteins. These proteins contribute to ITCs formation in sprouts under the combined treatment. These findings support the HSS as a novel regulatory strategy to enhance the nutritional value of broccoli sprouts and lay the foundation for the development of functional foods based on broccoli sprouts.