Physicochemical characteristics of local royal jelly produced in Al-Baha region, Saudi Arabia

Abstract

Royal jelly (RJ) consumption is expanding because of its high nutritional and bioactive content. However, there is a lack of information to standardize the limit of properties of Saudi Royal Jelly for regulation. The aim of this study is to investigate the quality of Saudi royal jelly associated with the international standard. Twelve fresh royal jelly samples were analyzed for moisture, pH value, total acidity, protein, carbohydrate composition, and 10-hydroxydec-2-enoic acid (10-HAD) concentration. The result of physicochemical properties was varied from 61.70 % to76.80 % for moisture; 3.14 to 3.83 for pH; 39.4 to 45.0 mL for free acidity; 0.1 N NaOH/100 g; 571.60 to 745.80 µS/cm for electrical conductivity (EC); 6.73% to 13.27% for crude protein content. Moreover, the 10-HDA, fructose, glucose, sucrose, maltose, and lactose content were ranged from 1.68% to 6.36%, 2.51 to 5.71%, 0.00% to 2.64%, 0.00% to 2.01% and 0.00 to 0.69%, respectively. The obtained results indicated that all samples matched the international standard and Gulf Standardization Organization (GSO ISO 12824:2021) for royal jelly requirements in terms of 10-HDA concentration, one of the most critical quality parameters. The statistical analysis showed a significant positive correlation (r=0.487, P < 0.01) between the EC and the total protein content while negative correlation between EC and sucrose content (r=-0.825, P < 0.01) and 10HDA (r= -0.699, P < 0.01); fructose and glucose content were shown to be statistically significant (r=0.887). The obtained results of present study will assist to the establishment of a standards of the Saudi royal jelly.