Factors Affecting Food Emulsion Properties - Home | UMass Amherst

35 Pages·2008·1.29 MB·English

Factors Affecting Food
Emulsion Properties
D. Julian McClements
Department of Food Science
University of Massachusetts , Amherst
Emulsion Properties Depend on
Droplet Characteristics
• Fat droplets affect:
– Appearance
– Flavor
– Texture
– Shelf-life
Need to Understand Role of Fat Droplets !
Emulsion Appearance
Optical Properties Determine:
• Product Desirability
• Perceived Product Quality
• Consumer Sensory Expectations
Influence of Fat Droplets on
Emulsion Appearance
Transmitted
Incident Wave, I(λ)
Wave, T(λ)
Reflected Wave, R(λ)
• Absorption
• Scattering
Emulsion Appearance:
Effect of Droplet Concentration
Hexadecane oil-in-water emulsions (d = 0.3 µm, red dye = 0.1%)
Emulsion Appearance:
Effect of Droplet Concentration
Lightness Color Intensity
100 50
40
Fading
80
30
L c
20
60
10
40 0
0 5 10 15 20 25 0 5 10 15 20 25
Droplet Concentration Droplet Concentration
(wt%) (wt%)
Hexadecane oil-in-water emulsions (d = 0.3 µm, red dye = 0.1%)
Emulsion Appearance:
Influence of Titanium Dioxide
90
80
Hexadecane oil-in-water emulsions
70 TiO
(d = 0.3 µm, red dye = 0.1%)
2
L
60
0%
0.04%
0.10%
50
0.30%
40
0 5 10 15 20 25
Droplet Concentration (wt%)
• Emulsion opacity can be increased by incorporating particles
that effectively scatter light, but are legally acceptable, relatively
inexpensive and compatible with the product
Emulsion Appearance:
Effect of Droplet Size
Lightness Color Intensity
50
80
45
40
70
L C
35
60
30
50 25
0 10 20 30 0 10 20 30
Droplet Diameter (µµµµm) Droplet Diameter (µµµµm)
Hexadecane oil-in-water emulsions (φ = 10%, red dye = 0.1%)
Emulsion Appearance:
Effect of Refractive Index
n /n = 1
d aq
Important for high sugar or polyol foods, or for analysis
Hexadecane oil-in-water emulsions (φ = 4 wt%, d = 1 µm, 0.002% Red Dye)
Main Factors Affecting Emulsion
Appearance
• Droplet Size & Concentration
• Relative Refractive Index
• Dye Type & Concentration
Theoretical models available to
predict emulsion color