Sugar, mineral, B-vitamins profiles and radical scavenging activity of Royal jelly collected at different harvesting times

Royal jelly is produced by young worker honeybees that support the growth of their larvae. Human beings can harvest and use it as functional food due to its high content of nutrients and beneficial human health effects. This study aims to investigate how harvesting time affects sugar and minerals, B vitamins profiles, and antioxidant (free radical scavenging) activity. Royal jelly samples were collected at third and sixth days of secretion and deposition by honeybees (Apis mellifera) in Holeta Bee Research Center, Ethiopia. Sugar, minerals and B-vitamins profiles and radical scavenging potential were examined by using standard methods. The highest sugar level was fructose (0.48 ± 0.03%) and the lowest was maltose (0.05 ± 0.01%) harvested on the third and sixth days, respectively and significant difference (ρ < 0.05) among fructose and sucrose. The minerals concentrations in descending order are K (4144.32 ± 174.98 mg/kg)> Mg (309.61 ± 8.33 mg/kg)> Ca (235.26 ± 1.05 mg/kg)> Na (155.60 ± 1.76 mg/kg) and the most abundant elements in royal jelly and significantly vary (ρ < 0.05) based on harvesting time, except in Mg. The highest vitamin content was vitamin B9 (14.8 ± 0.07 mg/kg) and the lowest was vitamin B3 (0.57 ± 0.06 mg/kg) harvested on third and sixth days, respectively and significant difference (ρ < 0.05). Royal jelly exhibited the strongest free radical scavenging activity (75.38%) and the lowest (59.97%), collected from the third and sixth days respectively and significant difference (ρ < 0.05). The inhibition concentration (IC50) value of royal jelly collected on third and sixth was 4.84% and 6.56%, respectively. Thus, the evaluated nutritional components and antioxidant properties in the royal jelly altered through harvesting times, and varied between royal jelly collected at different times, and found that royal jelly collected at third days more nutritious.