Table 1.
Compounds | Percentage | Examples | References |
---|---|---|---|
Moisture | 50–70% | Mainly water. | [96,98,99] |
Carbohydrates | 7.5–16% | Sugars such as fructose, glucose, maltose, melibiose, and ribose. | [98,99] |
Proteins | 9–18% | MRJPs (80% of protein content), minor proteins (e.g., aspimin, royalisin and jelleines), peptides (in the form of dipeptides or tripeptides, e.g., alanine-leucine, leucine- aspartic acid-arginine), and free amino acids (e.g., threonine, valine, glycine, isoleucine, leucine, proline, serine, methionine, and tryptophan). | [63,99,102] |
Lipidsa | 3–6% | 10-HDA, sebacic acid, phenols (4–10%), waxes (5–6%), steroids (3–4%), and phospholipids (0.4–0.8%). | [63,98,99,101,102] |
Vitamins | ? | B5 (52.8 mg/100 g), B6 (42.42 mg/100 g), niacin (42.42 mg/100 g), and traces of B1, B2, B8, B9, B12, ascorbic acid (vitamin C), vitamin E and A. | [63,102] |
Minerals | ? | Potassium, sodium, magnesium, calcium, phosphor, sulfur, cupper, iron, zinc, selenium, barium, cobalt, manganese, etc. | [42,63,98] |
Bioactive compounds | ? | ACh and nucleotides both as free bases (e.g., adenosine, guanosine, iridin, and cytidine) and as phosphates (e.g., adenosine 5′-monophosphate, adenosine 5′-diphosphate, and adenosine 5′-triphosphate). | [63,102] |
Others | ? | Volatile organic compounds (e.g., esters, aldehydes, ketones, and alcohols), and minor heterocyclic compounds. | [63,98,102] |
Abbreviations: MRJPs: major royal jelly proteins, 10-HDA: Trans-10-hydroxy-2-decenoic acid, ACh: acetylcholine. N.B. percentages of constituents are reported in fresh RJ, and data on the percentages of RJ constituents denoted by “?” are not clearly available.