Metabolic profiling unravels the effects of enhanced output and harvesting time on royal jelly quality.

Abstract

Royal jelly (RJ), a natural secretion of nurse bees, is a functional food with health-promoting properties. To investigate RJ quality changes with enhanced output and harvesting time, we compared metabolic profiles of RJ harvested at 24\xa0h, 48\xa0h, and 72\xa0h after larval grafting into queen cells from Italian bees (ITBs) and high RJ-producing bees (RJBs) selected from ITBs. A total of 77 high-abundance compounds were identified with reverse-phase liquid chromatography- and hydrophilic interaction liquid chromatography-high-resolution mass spectrometry. Metabolite abundance, water content, and antibacterial activity were found largely unchanged between both bee strains, indicating that a similar RJ quality was achieved. Notably, the observed 10-hydroxy-2-decenoic acid content in RJBs (1.98%) and ITBs (2.41%) meet the standard for premium RJ in China. RJ harvested at 48\xa0h and 72\xa0h had similar metabolic profiles, indicating little influence of the two harvesting times on RJ quality. The harvesting at 24\xa0h could lead to a higher RJ quality with higher abundance levels of many bioactive compounds and lower water content. Our data based mainly on RJ metabolic composition constitute evidence for mass production of high-quality RJ.