The document discusses color measurement and summarizes key aspects. It begins by explaining that color is the sensation of light in the visible spectrum perceived by the eye. Color measurement involves using instruments like a colorimeter or spectrophotometer to objectively quantify color values such as brightness, hue, and saturation. The document then summarizes experiments measuring the color of various samples and the effects of factors like target size, optical path length, and pH on color values.

1. THEORY & PRINCIPLE
OF COLOR
MEASUREMENT

2. COLOR??
COLOR : the sensation –
experienced by individual- radiant
energy within –light visible
spectrum (400-800 nm) –retina of
eye.
COLORANT : pigment that is used
to color a product.
COLORIMETRY : the science of color

3. COLOR
PERCEPTION

4. Things required to see
color
A light source
observer
object

5. A light sources
- normally emits light that appears
to be white
- when the light is dispersed by a
prism it is seen to be made up to all
visible wavelength

6. Object
-object modify light
- colorants such pigments or dyes
, in the object selectively absorb
some wavelengths of the incident
light while reflecting or
transmitting others

7. -luminosity is the relative -rod shaped receptors in
sensitivity of the human the eye are responsible
eye to various wavelength for night vision
of light
Observer
- there are three types
-cone shaped receptors of cones shaped
are responsible for day receptors sensitive to
light and color vision red , green and blue

8. Factors different perception
• different direction (angle)
• different sizes --> color different
e.g small more darker
• different background --> different brightness
• different observer --> various color
• Different material --> solid, liquid
e.g liquid sample more dark
• Different cross-sectional of cell holder--> > thick
, > darker

9. COLOR
MEASUREMENT

10. Things required to see color
To see color: to measure color:
Light sources Light sources
Object Specimen
Observers Spectrometer

11. Measuring color
A colorimeter spectrophotometer or
spectrophotometer

12. Color scales

13. Visual organization of color
Visual organizations of color:
-color has a degree of lightness or value
- hue is the color from the rainbow or spectrum or colors
- colorant can be added or increase the amount of chroma or saturation
Measured color values:
-visual methods of specifying color are subjective
- measuring color using an instrument gives objective results

14. Quantification of color
-brightness (lightness, L)
 light or dark
- color tone (hue, H)
- saturation (chrome, C)
 vivid : more vivid, saturated
 subdued

15. Amount of green-red (-a to +a)
Amount yellow-or-blue (+b to -
b)
The brightness (or
lightness,L) based on the
amount of light reflected or
transmitted.

16. Color opponent theory
State that the red, green and blue cone
responses are re-mixed into opponent coders
as they move up the optic nerve to the brain

17. Importance Of Colour Measurement
As A Quality Control Tool
● Uniform
● Specific
● Attraction
● Providing a colorful identity to products
that would otherwise have little colour

18. CIE Colour Space or Colour Model

19. Lightness (*L)
Chroma (*c)
Hue (*h)

20. ● Delta E
● difference between two colour samples
● show how far apart the two samples are in the colour
'sphere' visually

21. Tips for selecting the right color
management instruments
● Select instruments with good repeatability
● Ensure instruments have sufficient
measurement area
● Software that goes with the colour
measuring instruments

22. Observations

23. Part 1
• Colour measurement of
– liquid (distilled water) and
– solid sample (Washington apple)

24. Table 1: Values of L, C and H for distilled water
Average Std. Dev
L 30.27333 1.589727
C 22.69667 3.466588
H 21.73333 0.638148
Table 2: Values of L, C and H for Washington Apple
Average Std. Dev
L 88.64667 0.005774
C 138.0233 0.005774
H 85.74333 0.005774

25. Figure 1: CIELAB Colour Space

26. Part 2
• The effect of target mask size on colour
parameters
– Sample used: US Enza Jazz apple
– Target mask sizes
• 3mm
• 11mm
• 36mm

27. Table 3: Value of L, C and H of US Enza Jazz apple using different target mask sizes
Aperture's Size (mm) L C H
3 40.408 25.497 39.534
11 52.298 43.046 43.977
36 56.195 50.16 44.439
Comparison of L,C and H between different target mask sizes
60
50
40
L
30
C
20 H
10
0
0 5 10 15 20 25 30 35 40

28. Part 3
• Effect of optical path length on colour
parameters
– Sample used
• DNS Solution
– Thickness of cell holder used
• 2mm
• 10mm
• 20mm

29. Table 4: Value of L, C and H of DNS solution using different thickness of cell holders
Cell thickness (mm) L C H
2 88.677 137.993 86.091
10 81.545 140.154 77.577
20 76.85 136.319 73.469
Value of L, C and H of DNS solution using different cell holder
thickness
160
140
120
100
L
80
C
60
H
40
20
0
0 5 10 15 20 25

30. Part 4
• Effect of pH on the colour values of red
cabbage
– Sample used
• Red Cabbage
– pH used
• 3
• 5
• 7
• 9
• 11

31. Table 4: Value of L, C and H of red cabbage of different pH
pH L C H
3 81.62 39.2967 343.613
5 90.53 13.1133 317.543
7 85.6067 24.5267 171.977
9 95.7667 37.01 107.53
11 96.83 38.0333 103.187
Value of L, C and H of red cabbage in different pH
400
350
300
250
L
200
C
150
H
100
50
0
0 2 4 6 8 10 12

32. References
• http://www.rpdms.com/cielch/index.html
• http://allfreshkosher.com/red-delicious-washington-apples-extra-fancy-
xl.html
• http://www.chem.uiuc.edu/webfunchem/grammoleprob/GramMoleProb
2.htm
• http://www.arboschwin.com/index.php?page=hr1
• http://fitlifestyle.blogspot.com/2011/06/healthier-with-red-cabbage.html

33. STARCH
• Predominant food reserve substances in plant
• Provides 70-80% of the calories consumed by human.
• Made up from polysaccharide and commonly found in food

34. Source of starch
• Cereal grain seeds
– Corn
– Wheat
– Rice
• Tubers and Roots
– Potato
– Tapioca
– Arrowroot
• Peas
• Sago

35. Amylose
Starch
Amylopectin

36. Amylose
• Straight-chain glucose polymer
• Account 15% - 20% of starch
• Connected by α-1,4-glycosidic bonds
• Molecular weight ranging from 105-106

37. Amylopectin
• Very highly branched molecule
• Much larger size that amylose
• Branches of the amylopectin molecules are clustered
and occur as double helix
• Glucose units are linked by α-1, 4-glycosidic bonds and
α-1, 6-glycosidic bonds
1
6

38. Starch granule
• Made up of amylose and amylopectin molecule arranged
radially
• contain both crystalline and non-crystalline regions in
alternating layer.
• The clustered branches of amylopectin occur as packed
double helix
• packing together of double-helical structures forms small
crystalline lamellae.
• more dense of starch granule, which alternate with less dense
amorphous layers, contain greater amounts of the crystalline
lamellae.

39. Potato
starch
granule
2µm
Corn starch
granule

40. General Properties of Potato Starch and
Corn starch
Starch Granule Amylose Amylopectin Pasting Viscosity Paste Fat Protein Phosph
size, % % temperature, clarity % % orus %
μm ⁰C
Potato 5-100 21 79 56-65 Very high Clear 0.1 0.10 0.08
Corn 2-30 28 72 62-80 Medium Opaque 0.8 0.35 0.00

41. Starch granules contain both linear amylose
and branched amylopectin.

42. Raw, uncooked starch granules heated in water

43. Swelling is evident

45. Some granules have collapsed

46. Amylose Amylopectin
Do not contribute Give viscosity to cooked
significantly to viscosity paste
For formation of gel Do not contribute to
gel formation

47. Advantages:
1. Uses small
sample size
2. Short testing time
3. Ability to modify
testing conditions

48. Rapid Visco Analyser (RVA)
indicates starch viscosity by
measuring the resistance of flour and
water slurry to the stirring action of
a paddle.

49. RELEVANT OF PASTING
PARAMETERS TO PROCESSING
STEPS CONSIDERATION

50. pasting temperature
• Temperature at initial swelling of starch
granule,takes place when suspended in water.
• Heating starch granules in suspension in water
cause water penetrates the granules to
hydrate them and resulting swelling.
• provide indication of minimum temperature
required to cook.

51. peak viscosity
• the highest viscosity reached during
gelatinization of starch
• occurs prior to the initiation of sample cooling
• indicate water binding capacity of starch

52. breakdown viscosity
• rate of breakdown in viscosity to a holding
strength, hot paste viscosity or trough.
• depend on temperature and degree of mixing
or shear rate applied to the mixture and the
nature of material.

53. final viscosity
• the increase in viscosity during cooling of
paste.
• a measure of retrogradation due to
reassociation of the starch molecules

54. setback viscosity
• reassociation between starch molecules
during cooling.
• involve retrogradationor re-ordering of the
starch molecules and has been correlated with
texture of various products.

55. DIFFERENCE IN PASTING
PARAMETERS FOR CORN STARCH
AND POTATO STARCH

56. peak viscosity Peak
temperature
breakdown
Pasting
temperature
Total setback
Holding strength
pasting curve for potato starch

57. Peak
peak viscosity temperature
Total setback
Pasting
temperature
breakdown
Holding strength
pasting curve for corn starch

58. potato
starch
corn starch
potato starch
corn starch

59. • pasting temperature of corn starch higher than
potato starch. It is about 63.5°C for potato starch
and about 75.05°C for cornstarch.
• larger granules gelatinizing at lower temperature
and swelling more rapidly than small ones.

60. •peak viscosity for potato starch is 6069 cP and for
corn starch is 2899cP.
•potato starch granules are much larger and, as a
result, swell more easily.
• Large starch granules tend to build higher
viscosity

61. •breakdown viscosity for cornstarch is lower than potato
starch. for corn starch it is 1037 and for potato starch it is
4237.
•Viscosity break-down is the result of the molecule chain
lengths being broken caused by heat.
•The larger size of granule,the less molecular bonding so it
will breakdown faster.

62. • final viscosity of cornstarch is slightly higher than potato
starch.
• due to higher amylose content in corn starch compared to
potato starch.
• corn starch has a higher setback value compared to potato
starch
• the amylose in corn starch reassociate more readily.
• retrogradation occurs due to association of linear amylose
molecules, which can give rise to “setback”.