First Experiment by Chan Ka Man (3035574543)
First Experiment - How different types of emulsifier and stabilizer affect the stability of the vinaigrette
Before cooking
What ingredients and equipment needed?
- 100 ml of Cooking Oil
- 300 ml of Grape Vinegar
- 2.5 ml of Honey
- 2.5cm3 of Cheese
- 1 Egg yolk
- 4 glass containers with lid
- Measuring cup
- Measuring spoon
- Calliper
Who does the shopping?
Me and my mother.
Me and my mother.
Where to obtain ingredients/equipment/tools?
There are all obtained from my home.
There are all obtained from my home.
Where do I cook?
In my home, mainly in the dining room.
In my home, mainly in the dining room.
Objective:
To find out how effective certain ingredients are in emulsifying and stabilizing oil and vinegar, and find the type or combination of emulsifier and stabilizer that can best stabilize the vinaigrette.
Why is this investigation important?
There exist many websites talking about emulsifiers, yet there are some ingredients that they cannot seem to agree with, and they seem to mix up emulsifiers and stabilizers. This investigation aims to check if their claims are correct, and if so, how effective they are in emulsifying and stabilizing oil and vinegar.
Why these ingredients?
Cheese: The emulsifiers Sodium Phosphates are used during the production of cheese, and cheese is recommended as an emulsifier on some websites. Theoretically, if molten cheese is added into the mixture, the sodium phosphates in the cheese should emulsify the oil and vinegar.
Honey: It is commonly treated as an emulsifier and stabilizer on many websites, yet its effect is unknown. I aim to compare its emulsifying and stabilizing effect to other emulsifiers to see if they are comparable.
Egg yolk: It is a very common emulsifier, and is often treated as one of the strongest emulsifiers. It is used as a comparison to the other 2 questionable emulsifiers.
Why vote out some ingredients?
Salt and pepper: Vinaigrette usually contains salt and pepper as seasonings. However, they are not necessary, so in order to keep the experiment simple, and to better control the experiment, they are voted.
Mustard: Mustard is a very common emulsifier. However, since it is hard to obtain during this time, and it does not go very well with the recipe of grape vinaigrette, it is voted out.
Hypothesis:
Egg yolk has the strongest emulsifying and stabilizing effect, followed by honey, then cheese.
To find out how effective certain ingredients are in emulsifying and stabilizing oil and vinegar, and find the type or combination of emulsifier and stabilizer that can best stabilize the vinaigrette.
Why is this investigation important?
There exist many websites talking about emulsifiers, yet there are some ingredients that they cannot seem to agree with, and they seem to mix up emulsifiers and stabilizers. This investigation aims to check if their claims are correct, and if so, how effective they are in emulsifying and stabilizing oil and vinegar.
Why these ingredients?
Cheese: The emulsifiers Sodium Phosphates are used during the production of cheese, and cheese is recommended as an emulsifier on some websites. Theoretically, if molten cheese is added into the mixture, the sodium phosphates in the cheese should emulsify the oil and vinegar.
Honey: It is commonly treated as an emulsifier and stabilizer on many websites, yet its effect is unknown. I aim to compare its emulsifying and stabilizing effect to other emulsifiers to see if they are comparable.
Egg yolk: It is a very common emulsifier, and is often treated as one of the strongest emulsifiers. It is used as a comparison to the other 2 questionable emulsifiers.
Why vote out some ingredients?
Salt and pepper: Vinaigrette usually contains salt and pepper as seasonings. However, they are not necessary, so in order to keep the experiment simple, and to better control the experiment, they are voted.
Mustard: Mustard is a very common emulsifier. However, since it is hard to obtain during this time, and it does not go very well with the recipe of grape vinaigrette, it is voted out.
Hypothesis:
Egg yolk has the strongest emulsifying and stabilizing effect, followed by honey, then cheese.
While cooking
1. Use the measuring cup to obtain 75ml of vinegar and pour it into a glass container. Repeat the process for all 4 containers.
2. Use the measuring spoons to add 25ml of oil into the 4 containers respectively.
3. Use the measuring spoons to obtain 2.5cm3 of cheese. Heat up the cheese using the microwave until it is molten and add it into one of the containers. Replace the cheese with honey and egg yolk respectively and repeat the process.
Use a knife to assist in measuring the cheese.
Adding honey into a container.
Preparing for the egg yolk.
Egg white and egg yolk separated.
Adding egg yolk into a container.
4. Close the lids to the containers. Shake them to mix the mixture inside thoroughly. Observe the clarity of the mixture and measure the average diameter of the oil droplets.
After cooking
Observation:
Upon mixing, the oil and vinegar appear to have mixed thoroughly in all 4 mixtures.
After 30 seconds, the oil and vinegar in all 4 mixtures separated into 2 layers.
Observation of the vinegar layer:
Observation of the vinegar layer:
Cheese
|
Honey
|
Egg
Yolk
|
Control
|
|
30
seconds
|
Mildly
milky
|
Slightly
milky
|
Very
milky
|
Clear
|
5
minutes
|
Mildly
milky
|
Slightly
milky
|
Very
milky
|
Clear
|
30
minutes
|
Mildly
milky
|
Slightly
milky
|
Very
milky
|
Clear
|
1
hour
|
Slightly
milky
|
Clear
|
Very
milky
|
Clear
|
4
hours
|
Slightly
milky, decolourized, the cheese precipitation changed from white to purple
|
Clear
|
Very
milky
|
Clear
|
The 4 mixtures after 5 minutes.
The clarity of the 4 mixtures.
Observation of the oil layer:
Cheese
|
Honey
|
Egg
Yolk
|
Control
|
|
30
seconds
|
Entire
oil layer made of oil droplets with average diameter 1.0mm
|
Entire
oil layer made of oil droplets with average diameter 0.6mm
|
Entire
oil layer made of oil droplets with average diameter 0.6mm
|
Entire
oil layer made of oil droplets with average diameter 1.2mm
|
5
minutes
|
About
2/3 of the oil layer has settled, forming a single merged layer, the rest of
it remains as droplets with an average diameter of 2.2mm.
|
The
oil droplets don’t merge with an average diameter of 1.1mm.
|
The
oil droplets don’t merge with an average diameter of 0.8mm.
|
Oil
droplets have settled, forming a single merged layer with a few large droplets.
|
30
minutes
|
About
3/4 of the oil layer has settled, forming a single merged layer, the rest of
it remains as droplets at the base of the layer with an average diameter of
2.2mm.
|
The
oil droplets don’t merge with an average diameter of 1.3mm.
|
Some
oil droplets merged to form larger droplets with an average diameter of 5.0mm,
the rest of it remains as droplets beneath the large droplets with average the diameter of 0.8mm.
|
Oil
droplets have settled, forming a single merged layer with no visible droplets.
|
1
hour
|
About
3/4 of the oil layer has settled, forming a single merged layer, the rest of
it remains as droplets at the base of the layer with an average diameter of
2.2mm.
|
The
oil droplets don’t merge with an average diameter of 1.3mm.
|
Some
oil droplets merged to form larger droplets with an average diameter of 5.0mm,
the rest of it remains as droplets beneath the large droplets with average the diameter of 0.8mm.
|
Oil
droplets have settled, forming a single merged layer with no visible droplets.
|
4
hours
|
About
3/4 of the oil layer has settled, forming a single merged layer, the rest of
it remains as droplets at the base of the layer with an average diameter of
2.2mm.
|
The
oil droplets don’t merge with an average diameter of 1.5mm.
|
About 1/2 of the oil droplets merged to form a layer of larger droplets,
the rest of it remains as droplets beneath the large droplets with average the diameter of 0.8mm.
|
Oil
droplets have settled, forming a single merged layer with no visible droplets.
|
The 4 mixtures after 4 hours.
Analysis:
Result:
- Comparing with the control, all 3 ingredients can be observed to have an emulsifying or stabilizing effect to some degree.
- Emulsified mixtures have a significantly lower clarity when compared to the ones without an emulsifier. From the comparison of the clarity of the vinegar layers, egg yolk has the strongest emulsifying effect among the 3 ingredients used; on the contrary, considering the slight clarity change after the addition of cheese and honey, these 2 ingredients have a weaker emulsifying effect.
- Stabilizers prevent oil droplets from merging, giving the mixture a lower clarity in the process. From the comparison of the oil layers, honey has the strongest stabilizing effect among the 3 ingredients, followed by egg yolk, then cheese.
Result:
- Comparing with the control, all 3 ingredients can be observed to have an emulsifying or stabilizing effect to some degree.
- Emulsified mixtures have a significantly lower clarity when compared to the ones without an emulsifier. From the comparison of the clarity of the vinegar layers, egg yolk has the strongest emulsifying effect among the 3 ingredients used; on the contrary, considering the slight clarity change after the addition of cheese and honey, these 2 ingredients have a weaker emulsifying effect.
- Stabilizers prevent oil droplets from merging, giving the mixture a lower clarity in the process. From the comparison of the oil layers, honey has the strongest stabilizing effect among the 3 ingredients, followed by egg yolk, then cheese.
Discussion:
- Considering the different strengths of the emulsifying and stabilizing effect of the 3 ingredients, it can be concluded that emulsifier and stabilizer have to be both added into the vinaigrette in order to give it optimal stability.
- Egg yolk has a very strong emulsifying effect, yet a relatively weak stabilizing effect. This leads to effective emulsification after mixing. However, after a long period of time, its weak stabilizing effect leads to the oil droplets to merge, forming larger droplets and even a single oil layer.
- Honey has a very strong stabilizing effect, yet a very weak emulsifying effect. This leads to a relatively quick separation of the oil and vinegar after mixing. However, its strong stabilizing effect prevents the oil droplets from merging even after a long period of time.
- Cheese has very weak emulsifying and stabilizing effects. This could be due to the emulsifiers and stabilizers used when producing cheese have already firmly bonded to the molecules of cheese. Thus, only a small amount of emulsifier and stabilizer are released and thus emulsify and stabilize the oil and vinegar, leading to a lower clarity after mixing and a small amount of oil droplets not merging with the oil layer.
- After leaving the mixtures to settle for 4 hours, the one that has cheese added undergoes an unexpected colour change. The vinegar layer changes from purple to pale yellow while the cheese precipitations at the bottom changes from white to purple. It is speculated that the cheese molecule or an ingredient used in the making of cheese absorbs the colourings in the grape vinegar, thus decolorizing it.
Possible errors and how they can be improved:
- Since the scale on the measuring cup is relatively large, the about of vinegar may not be very precise. To reduce the error, a measuring cylinder or measuring spoons could be used instead.
- Since the mixtures are mixed by hand, the time of mixing for the 4 mixtures may not be completely identical. To improve, an electric mixer could be used.
- Since the cheese is molten, the mixture which contains cheese has a higher temperature than the other 3, which may affect the result. To improve, the other 3 mixtures could be heated up as well.
- Although a calliper with a resolution of 0.05mm us used, it is still hard to accurately measure the average diameter of oil droplets. To improve, the density of the oil droplets may be measured as a better approximation.
- The comparison of the clarity of the vinegar layer may not be accurate as it is observed objectively. To improve, a transparency meter may be used.
Further investigation:
- Since the mixture that contains cheese undergoes an unexpected colour change over time, further investigation could be conducted to understand the principle behind it.
- A larger variety of emulsifiers and stabilizers can be used and experimented to better find out their emulsifying and stabilizing effects.
- Since emulsifiers and stabilizers could be used as a combination, experiments could be conducted to find out the combination of the 2 that could best stabilize vinaigrette.
- Considering the different strengths of the emulsifying and stabilizing effect of the 3 ingredients, it can be concluded that emulsifier and stabilizer have to be both added into the vinaigrette in order to give it optimal stability.
- Egg yolk has a very strong emulsifying effect, yet a relatively weak stabilizing effect. This leads to effective emulsification after mixing. However, after a long period of time, its weak stabilizing effect leads to the oil droplets to merge, forming larger droplets and even a single oil layer.
- Honey has a very strong stabilizing effect, yet a very weak emulsifying effect. This leads to a relatively quick separation of the oil and vinegar after mixing. However, its strong stabilizing effect prevents the oil droplets from merging even after a long period of time.
- Cheese has very weak emulsifying and stabilizing effects. This could be due to the emulsifiers and stabilizers used when producing cheese have already firmly bonded to the molecules of cheese. Thus, only a small amount of emulsifier and stabilizer are released and thus emulsify and stabilize the oil and vinegar, leading to a lower clarity after mixing and a small amount of oil droplets not merging with the oil layer.
- After leaving the mixtures to settle for 4 hours, the one that has cheese added undergoes an unexpected colour change. The vinegar layer changes from purple to pale yellow while the cheese precipitations at the bottom changes from white to purple. It is speculated that the cheese molecule or an ingredient used in the making of cheese absorbs the colourings in the grape vinegar, thus decolorizing it.
After 4 hours, the mixture containing cheese decolourized.
Possible errors and how they can be improved:
- Since the scale on the measuring cup is relatively large, the about of vinegar may not be very precise. To reduce the error, a measuring cylinder or measuring spoons could be used instead.
- Since the mixtures are mixed by hand, the time of mixing for the 4 mixtures may not be completely identical. To improve, an electric mixer could be used.
- Since the cheese is molten, the mixture which contains cheese has a higher temperature than the other 3, which may affect the result. To improve, the other 3 mixtures could be heated up as well.
- Although a calliper with a resolution of 0.05mm us used, it is still hard to accurately measure the average diameter of oil droplets. To improve, the density of the oil droplets may be measured as a better approximation.
- The comparison of the clarity of the vinegar layer may not be accurate as it is observed objectively. To improve, a transparency meter may be used.
Further investigation:
- Since the mixture that contains cheese undergoes an unexpected colour change over time, further investigation could be conducted to understand the principle behind it.
- A larger variety of emulsifiers and stabilizers can be used and experimented to better find out their emulsifying and stabilizing effects.
- Since emulsifiers and stabilizers could be used as a combination, experiments could be conducted to find out the combination of the 2 that could best stabilize vinaigrette.
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