Determination of amino acids and protein content in fresh and commercial royal jelly from Bulgaria
Royal jelly (RJ) is popular among consumers around the world due to its perceived health benefits. The purpose of this study was to assess the levels of free and total amino acid profile as well as protein content in order to characterize Bulgarian RJ samples. A total of 17 fresh and commercial RJ samples from different regions of Bulgaria were analyzed. The results obtained show that proline (Pro), lysine (Lys), methionine (Met), aspartic acid (Asp), cysteine (Cys), histidine (His) were major free amino acids (FAAs) in RJ. The average content of Pro was 2.3 mg/g. The FAA content ranged from 5.5 to 6.2 mg/g of RJ. The most abundant total amino acids (TAAs) were aspartic acid (Asp), glutamic acid (Glu), lysine (Lys), leucine (Leu), serine (Ser) and proline (Pro). The average TAA content in fresh and commercial RJ were 129±10 and 114±8 mg/g, respectively. The results obtained for TAA content were used to establish a range for amino acid composition of Bulgarian RJ. The content of proteins was higher in fresh RJ than in commercial samples and this difference was significant (p<0.05). The following ranges were observed for fresh and commercial samples 14.7–17.3 and 12.5–14.9 mg/g, respectively.
KEY WORDS: Royal jelly (RJ), Free amino acids (FAAs), Total amino acids (TAAs), Protein content, Bulgaria
Bull. Chem. Soc. Ethiop. 2015, 29(3), 485-490.