Acacia – chemistry, sources, preparation, evaluation, preservation, storage, therapeutic uses and commercial utility is a vital topic for B. Pharm students. Acacia (gum arabic) is a natural, high-molecular-weight polysaccharide–glycoprotein complex from species like Acacia senegal and Acacia seyal. Key concepts include chemical composition (arabinogalactan, uronic acids), pharmaceutical roles (emulsifier, suspending agent, binder, demulcent), collection and purification (harvesting, ethanol precipitation), and quality evaluation (viscosity, ash, microbial limits, FT-IR fingerprinting). Proper preservation and storage (dry, airtight, cool conditions) ensure stability and commercial utility in food, cosmetics and pharma (E414). Clinical and prebiotic therapeutic uses are also important for formulation design. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is the primary chemical nature of gum acacia (gum arabic)?
- Polysaccharide
- Protein
- Lipid
- Alkaloid
Correct Answer: Polysaccharide
Q2. Which botanical species is the principal commercial source of gum arabic?
- Acacia senegal
- Acacia catechu
- Acacia auriculiformis
- Acacia nilotica
Correct Answer: Acacia senegal
Q3. What is the food additive (E-number) designation for gum arabic?
- E120
- E414
- E500
- E322
Correct Answer: E414
Q4. Which functional groups are prominent in the polysaccharide framework of gum acacia?
- Hydroxyl (–OH) and carboxyl (–COOH) groups
- Sulfate (–SO4) groups only
- Primary amine (–NH2) groups only
- Phosphate (–PO4) groups only
Correct Answer: Hydroxyl (–OH) and carboxyl (–COOH) groups
Q5. Which of the following best describes common pharmaceutical roles of gum acacia?
- Binder in tablets only
- Emulsifier in oil-in-water systems only
- Suspending agent only
- All of the above
Correct Answer: All of the above
Q6. Which physicochemical parameter is most critical for characterizing gum acacia performance in formulations?
- Melting point
- Viscosity of aqueous solutions
- Boiling point
- Flash point
Correct Answer: Viscosity of aqueous solutions
Q7. Gum acacia is readily soluble in which solvent?
- Water
- Absolute ethanol
- Chloroform
- Hexane
Correct Answer: Water
Q8. The recommended basic storage condition for commercial gum acacia is:
- Store in a cool, dry, airtight container away from moisture
- Keep refrigerated at below 0°C
- Store submerged in water to maintain hydration
- Expose to sunlight to maintain sterility
Correct Answer: Store in a cool, dry, airtight container away from moisture
Q9. Which classical chemical test is commonly used to indicate the presence of carbohydrates in gum samples?
- Biuret test
- Molisch’s test
- Sudan III test
- Dragendorff’s test
Correct Answer: Molisch’s test
Q10. The main monosaccharide units present in gum arabic are:
- Arabinose and galactose
- Glucose and fructose
- Ribose and deoxyribose
- Maltose and lactose
Correct Answer: Arabinose and galactose
Q11. Gum acacia stabilizes emulsions primarily by:
- Reducing oil viscosity
- Forming a protective interfacial film around droplets
- Acting as a strong acid to break emulsions
- Increasing droplet coalescence
Correct Answer: Forming a protective interfacial film around droplets
Q12. Chemically, gum arabic behaves predominantly as which type of polymer?
- Cationic polysaccharide
- Anionic polysaccharide
- Non-ionic synthetic polymer
- Zwitterionic peptide
Correct Answer: Anionic polysaccharide
Q13. Which quality parameter, when elevated, commonly indicates inorganic contamination or adulteration of gum acacia?
- Low moisture content
- High ash value
- High viscosity
- Low pH
Correct Answer: High ash value
Q14. Gum acacia is considered beneficial in the gut because it can act as a:
- Antibiotic
- Prebiotic dietary fiber
- Synthetic sweetener
- Strong acidifier
Correct Answer: Prebiotic dietary fiber
Q15. A common laboratory purification step for crude gum acacia is:
- Acid hydrolysis to monosaccharides
- Precipitation with ethanol to remove impurities
- Heating to 300°C to carbonize impurities
- Extraction with hexane to remove polysaccharides
Correct Answer: Precipitation with ethanol to remove impurities
Q16. Exposure of crude gum acacia to high humidity most likely causes:
- Improved solubility and sterilization
- Caking, clumping and increased microbial growth
- Reduction in molecular weight to monomers
- Instant sterilization and drying
Correct Answer: Caking, clumping and increased microbial growth
Q17. Which analytical technique is commonly used for fingerprint identification of gum acacia?
- UV-visible spectroscopy only
- Fourier-transform infrared spectroscopy (FT-IR)
- Polarimetry only
- Atomic absorption spectroscopy
Correct Answer: Fourier-transform infrared spectroscopy (FT-IR)
Q18. The molecular weight of gum arabic is best described as:
- Very low (less than 1 kDa)
- High molecular weight polysaccharide (approximately 10^4–10^6 Da)
- Exactly 100 Da
- Identical to monosaccharides
Correct Answer: High molecular weight polysaccharide (approximately 10^4–10^6 Da)
Q19. In pharmaceutical emulsions, gum acacia is primarily used as a(n):
- Emulsifying agent
- Preservative
- Organic solvent
- Oxidizing agent
Correct Answer: Emulsifying agent
Q20. Which major pharmacopoeias include official specifications for gum acacia?
- United States Pharmacopeia (USP) only
- British Pharmacopoeia (BP) only
- Indian Pharmacopoeia (IP) only
- All of the above
Correct Answer: All of the above
Q21. In the food industry, gum arabic is widely used as a:
- Coloring agent
- Stabilizer and emulsifier
- Primary protein supplement
- Preservative solvent
Correct Answer: Stabilizer and emulsifier
Q22. Prolonged heating of gum acacia solutions typically results in:
- Improved emulsifying capacity without any degradation
- Thermal degradation, color change and viscosity loss
- Conversion to pure glucose without any side effects
- Increase in molecular weight
Correct Answer: Thermal degradation, color change and viscosity loss
Q23. To determine the monosaccharide composition of gum acacia, which analytical approach is most appropriate?
- Direct UV spectroscopy of the intact gum
- Acid hydrolysis followed by GC-MS of derivatized sugars
- Simple filtration through a 0.22 μm filter
- Direct weighing on an analytical balance
Correct Answer: Acid hydrolysis followed by GC-MS of derivatized sugars
Q24. Which factors significantly influence the viscosity of gum acacia solutions?
- Concentration only
- Temperature only
- pH only
- Concentration, temperature and pH
Correct Answer: Concentration, temperature and pH
Q25. How is gum acacia best classified pharmaceutically?
- Natural gum
- Synthetic polymer
- Resin
- Inorganic salt
Correct Answer: Natural gum
Q26. Which therapeutic/formulative role is supported by gum arabic in cough syrups?
- Demulcent (soothing agent)
- Systemic antibiotic
- Local anesthetic
- Strong acidifier
Correct Answer: Demulcent (soothing agent)
Q27. For long-term preservation of bulk gum acacia, the best temperature recommendation is:
- Store in a cool, dry place below 30°C
- Keep at boiling temperature for sterilization
- Maintain frozen at −20°C
- Constant exposure to direct sunlight
Correct Answer: Store in a cool, dry place below 30°C
Q28. During laboratory purification, which solvent is commonly used to precipitate and purify gum fractions?
- Hexane
- Absolute ethanol
- Carbon tetrachloride
- Diethyl ether
Correct Answer: Absolute ethanol
Q29. A frequent adulterant of commercial gum acacia that reduces quality is:
- Starch
- Pure cellulose fibers only
- High-purity sucrose only
- Genuine gum tragacanth
Correct Answer: Starch
Q30. Which of the following therapeutic claims is supported for gum arabic in dietary use?
- Acts as a concentrated source of protein
- Functions as a prebiotic fiber improving gut microbiota
- Operates as a potent systemic steroid
- Serves as a primary antihypertensive drug
Correct Answer: Functions as a prebiotic fiber improving gut microbiota
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
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