Bee products as valuable nutritional ingredients: Determination of broad free amino acid profiles in bee pollen, royal jelly, and propolis

This study compared the amino acid content of three bee products: royal jelly, propolis, and bee pollen, which is a step toward improving the quality of nutrition and the safety of supplementation with these beneficial products of natural origin. The samples were collected from the hives of Apis mellifera bees in the apiaries located in Poland. A broad panel of free amino acids in bee products was determined using the highly selective liquid chromatography-tandem mass spectrometry method. We quantified 32 amino acids in bee pollen, 31 in royal jelly, and 28 in propolis. The most abundant essential amino acid in bee products was histidine in bee pollen (1.5 mg/g), lysine in royal jelly (2.05 mg/g) and valine in propolis (0.006 mg/g). Proline was the most abundant nonessential amino acid in all bee products and accounted for 6.7 mg/g; 1.4 mg/g; and 0.3 mg/g, in bee pollen, royal jelly, and propolis, respectively. Among the non-proteinogenic amino acids, gamma-amino-n-butyric acid was quantified in the highest concentrations in bee pollen (1.05 mg/g). Our study proved that bee products are characterized by specific profiles of free amino acids. In terms of protein and non-protein amino acid content, bee pollen is the most valuable bee product.