Hydrophile-Lipophile Balance

Question 1

Commercial food emulsifiers Hydrophilic part: (5)

Answer 1

glycerol, sorbitol, sucrose, propylene glycol or polyglycerol

Question 2

Commercial food emulsifiers lipophilic part:

Answer 2

fatty acid

Question 3

what to consider when Choosing an emulsifier?

Answer 3

what is the application ?

Do we want to disperse oil in water?
–> make the oil droplet hydrophilic
Do we want to disperse water in oil?
–> make the water droplet lipophilic

Question 4

what is Hydrophile-Lipophile Balance?

Answer 4

HLB is used extensively to predict surfactant properties of a molecule
–> expresses to what degree the molecule is hydrophilic or lipophilic

high HLB value corresponds to high water solubility

Useful to identify surfactants for oil and water emulsification

Question 5

Water-in-oil (w/o) emulsions require [HIGH / LOW] low HLB surfactants?

Answer 5

low HLB surfactants

–> more lipophilic

Question 6

Oil-in-water (o/w) emulsions require [HIGH / LOW] low HLB surfactants?

Answer 6

higher HLB surfactants

–> more hydrophilic

Question 7

HLB values scale

Answer 7

Scale of values ranging 0 to 20

Different oils require different HLB values

2~ antifoaming agents
3-6~ w/o emulsifying agents
7-8~ wetting/ spreading agents
8-16~ o/w emulsifying agents
13-15~ detergents
15-18~ solubilizing agents

Question 8

Griffin’s method

Answer 8

to describe the non-ionic surfactants:

HLB = 20 x ( M[h] / M )

M[h] = the molecular mass of the hydrophilic portion of the molecule
M = the molecular mass of the whole molecule

Question 9

Davies’ method

Answer 9

to describe and takes into account strength of groups:

HLB = 7 + (m x H[h] – n x H[l])

m = number of hydrophilic groups
n= number of lipophilic groups
H[h] = value of hydrophilic groups
H[l] = value of the lipophilic groups

Question 10

Mixed emulsifier systems

Answer 10

(HLB)[m] = XA + XB

X[A] = mass fraction of A
X[B] = mass fraction of B

Question 11

HLB value determination

Answer 11

Use mixtures of hydrophobic (Span) and hydrophilic surfactants (Tween)

Question 12

Typical HLB experiment

Answer 12

prepare 8 simple emulsions

• each with the same amount of oil
• each with the same amount of surfactant but with a different HLB value
• each with the same amount of water and mixing

observe which emulsion appears to be the most stable
- “stable” meaning here the one least separated or the one that separates last