Benxoic acid

Question 1

What is benzoic acid?

Answer 1

• Food molecule found in plants but commonly used as food preservative
• May have negative health effects
• Occur in some berries in small amounts

Question 2

Body mechanisms to deal with benzoic acid?

Answer 2

Humans have a
mechanism to modify and excrete benzoic acid which
is not utilized in our bodies.

Question 3

Structure of benzoic acid?

Answer 3

• Different to most other acids in living tissue as it has a benzene ring
• Aromatic properties due to sharing of electrons within the ring structure
• Simplest aromatic acid and has a carboxylic acids functional group attached to the ring

Question 4

Properties on benzoic acid?

Answer 4

Molecular formula: C7H6O2

Polarity: Relatively non-polar

Solubility: Very soluble in solvents and low water solubility (due to carboxylic group)

Question 5

Benzoic acid is monoprotic. What does this mean?

Answer 5

This means that it ionises once and this establishes an equilibrium, the position of which depends upon the pH conditions prevailing. It will therefore be at least partially ionised in many food products

Question 6

Benzoic acid as a food additive?

Answer 6

• Is a antimycotic (antifungal)
• Is a antibacterial
• Not that effective against food spoilage
• More effective against food poisoning and spore forming bacteria

Question 7

4 chemical forms for benzoic acid used as food additives?

Answer 7

• Benzoic acid:
• Calcium benzoate
• Potassium benzoate
• Sodium benzoate

These vary in terms of solubility. Important that oily the unionized form is active as preservative in foods

Question 8

Food pH and the use of benzoic acid?

Answer 8

• As the ionisation results in an equilibrium, unless we add a
  large amount of benzoic/benzoate additives,
  then the chemical form occurring in the food depends
  only on the pH of the food
• We know that only the unionised form of benzoic acid
  is effective as an anti-microbial agent

Question 9

Safety of benzoic acid?

Answer 9

• Concerns for health
• Aminal trials used to est. NOAEL values and ADI
• The total diet survey data found there is no cause for alarm in relation to the amount of benzoic acid present in the foods analysed

Question 10

Recent research on benzoic acid (health effects)?

Answer 10

• Possible cause for hyperactivity in children

- Few studies were done but the also used other additives so unable to know which one was the cause