Raffinose

Basic Information

Name: Raffinose

CAS No: b-D-Fructofuranosyl-O-a-D-galactopyranosyl-(1!6), a-D-glucopyranoside, anhydrous [512-69-6], b-D-Fructofuranosyl-O-a-D-galactopyranosyl-(1!6), a-D-glucopyranoside pentahydrate [17629-30-0]

Functional Categories

Stabilizing agent

1. Nonproprietary Names

None Adopted

2. Synonyms

Gossypose; melitose; melitriose; D-raffinose; D-(þ)-raffinose.

3. Chemical Name & CAS Registry

b-D-Fructofuranosyl-O-a-D-galactopyranosyl-(1!6), a-D-glucopyranoside, anhydrous [512-69-6], b-D-Fructofuranosyl-O-a-D-galactopyranosyl-(1!6), a-D-glucopyranoside pentahydrate [17629-30-0]

4. Empirical Formula & Molecular Weight

C18H32O16 504.44 (for anhydrous) C18H32O165H2O 594.52 (for pentahydrate)

5. Structural Formula

D-Raffinose anhydrou

6. Applications

Raffinose is a trisaccharide carbohydrate that is used as a bulking agent, blood substitute, stabilizing agent, and water scavenger in freeze-drying where it acts as a stabilizer for freeze-dried formulations.(1,2) It is also used as a crystallization inhibitor in sucrose solutions.(3–5)

7. Description

Raffinose is a white crystalline powder. It is odorless and has a sweet taste approximately 10% that of sucrose.(6)

9. Typical Properties

Collapse temperature –268C(2) Decomposition temperature 118–1198C (anhydrous); 1308C (pentahydrate).(7) Density (bulk) 0.67 g/cm3 (pentahydrate) Density (tapped) 0.98 g/cm3 (pentahydrate) Density (true) 1.465 g/cm3 (anhydrous) Diffusion coefficient (infinite dilution) 0.33 105 cm2 /s (water at 158C)(8) Glass transition temperature 1148C (amorphous)(9) Heat of solution at infinite dilution (258C) 52 kJ/mol (crystalline pentahydrate); –38 kJ/mol (amorphous).(1) Melting point 808C (pentahydrate);(7) 1188C (anhydrous).(10) Optical rotation 1058 (pentahydrate); 1238 (anhydrous).(11) Specific gravity 1.465 (pentahydrate)(7) Solubility in methanol 0.10 g/mL(11) Solubility in water 0.14 g/mL(7) Solubility Soluble 1 in 10 of methanol, in pyridine and 1 in 7.1 of water; soluble in ethanol (95%); insoluble in diethyl ether. The data for the crystal structure,(12,13) NMR structure,(14) powder x-ray diffraction pattern,(15) water vapor sorption isotherms,(15,16) glass transition temperature as a function of water,(15) heat capacity,(1) heat of solution properties,(1) vapor pressure,(17) and osmotic pressure(18) are described in the literature.

10. Stability & Storage

Raffinose is stable under ordinary conditions of use and storage. Excessive heat should be avoided to prevent degradation. Thermal decomposition products are carbon monoxide and carbon dioxide.(19,20)

11. Incompatibilities

Raffinose is incompatible with strong oxidizers.(21)

12. Method of Manufacture

Raffinose occurs naturally in Australian manna, cottonseed meal, and seeds of various food legumes. It can be isolated from beet sugar molasses through sucrose separation, seed-crystallization, and filtration.(13,22)

13. Safety

Raffinose is a naturally occurring trisaccharide investigated for use in freeze-dried pharmaceutical formulations. It occurs in a number of plants that are consumed widely

14. Handling Precautions

Observe normal precautions appropriate to the circumstances and quantity of material handled. Gloves and safety glasses are recommended. Dust generation should be kept to reasonable levels to avoid ignition or explosion. Short-term exposure has caused respiratory and eye irritation. Long-term exposure has shown adverse reproductive effects in animals. No occupational exposure limits have been established. Dust or air mixtures may ignite or explode.(19,20

15. Regulatory Status

Raffinose is a naturally occurring trisaccharide and is consumed as part of a normal diet.

16. Related Substances

Raffinose is composed of three monosaccharides: galactose, glucose, and fructose. It shares related structures with sucrose and melibiose. It is also related to stachyose, which possesses an additional (1!6)-linked a-D-galactopyranosyl unit. Two solvated forms(22) and an amorphous form(14,23,24) of raffinose can be synthesized

17. Comments

Raffinose has been shown to accumulate in organisms that can survive extreme desiccation, and has therefore been examined as an excipient in stabilizing co-lyophilized protein and labile preparations during storage at elevated temperatures.(25,26) When exposed to elevated relative humidity (RH) of 75% at 258C, raffinose has been shown to form different hydrate levels.(27) Raffinose is indigestible by humans because of a lack of an agalactosidase and undergoes fermentation in the colon, causing production of carbon dioxide, hydrogen, and methane gases.(10) The PubChem Compound ID (CID) for raffinose includes 10542, 219993, and 439242