Annex A - Group Research Proposal

Group Project Proposal (Science)


Names: Ang Liya, Rishita Subnavis, Kho Hannah

Class: S2-01

Group Reference: D

A.    Indicate the type of research that you are adopting:

[    ] Test a hypothesis: Hypothesis-driven research
e.g. Investigation of the antibacterial effect of chrysanthemum

[    ] Measure a value: Experimental research (I)
e.g. Determination of the mass of Jupiter using planetary photography

X ] Measure a function or relationship: Experimental research (II)
e.g. Investigation of the effect of temperature on the growth of crystals

[    ] Construct a model: Theoretical sciences and applied mathematics
e.g. Modeling of the cooling curve of naphthalene 

[    ] Observational and exploratory research
e.g. Investigation of the soil quality in School of Science and Technology, Singapore  

  1. Type & Category

Type of research: 3

Category  –  10

Sub-category –  e (Organic Chemistry)

Application of project relevant to SST Community, Society or the World:
Casein that is found in milk can be used to create plastics, fibres and paints. By using this protein, people can make use of milk to make biodegradable plastic and fibres that would not harm the environment when unwanted. The project can tell us which acidic liquid would work most well to create the casein from the milk so that the milk can be used to its maximum potential and create as much casein as possible.
Our project can be useful to the industry because people can use this idea to make other materials with milk, which is easily found.
It can also be useful to create paint, which can benefit artists. The casein-milk can be homemade, and helping to make use of the casein in milk, will allow people to use the paint and create art.

C.    Write down your research title:

Investigation of the effect of acids on curdling of milk

D.   (a) Aim / question being addressed 

 To find out about how the amounts of vinegar and other acids will affect the amount of curdling of casein in milk.

Q: How does the acidic liquid make the casein from milk?
A: Casein is a protein in milk which is insoluble, and when the vinegar is poured into the milk and turning it acidic, the casein reacts by precipitating and turning into clumps which can be separated from the rest of the milk.

Background research:
 In milk, casein is not dissolved, just suspended, so it can be filtered out of milk. Heating and boiling milk does not alter its state but dilute acids and rennet cause it to precipitate, stronger ones dissolve it.

 Casein is a protein that is commonly found in mammalian milk, making up at least 80% of the proteins in cow’s milk and between 20% to 45% of protein in human milk. Casein has a wide variety of uses, from being component of cheese, to use as a food additive, to a binder for safety matches. As a food source, casein supplies amino acids.

 Casein contains a fairly high number of proline residues, which do not interact. It is rather hydrophobic, making it poorly soluble in water. It is found in milk as a suspension of particles called “casein micelles” which show only relatively limited resemblance with other micelles in a sense that the hydrophilic parts reside at the surface and they are spherical.

 The isoelectric point of casein is 4.6. Since milk’s pH is 6.6, casein has a negative charge in milk. The purified protein is water-insoluble. While it is also insoluble in neutral salt solutions, it is readily dispersible in dilute alkalis and in salt solutions such as sodium oxalate and sodium acetate.

 Casein can also be used and/or found in paint glue, cheese making, plastics and fibre, protein supplements and other medical and dental uses.

 There is evidence that it has been used during the middle ages and it has been identified in 18th century ceiling paintings. However, there are problems using casein as paint because it is brittle and can become moldy.

(b) Independent variable

Acidic liquids:
  • Cider vinegar        (3.10 pH level)
  • Yuzu juice          (2.00 - 2.60 pH level)
  • Apple juice            (3.35 - 4.00 pH level)
  • Red wine               (2.90 - 3.90 pH level)
  • Aloe vera juice      (6.00 - 6.80 pH level)
  • Cola                      (2.30 - 3.50 pH level)
And the amount of acid added.

(c) Dependent variable

Weight of curd (casein)

(d) Controlled variables

(a)The starting amount and concentration of casein of the milk (same brand and type of milk) (eg. Marigold full cream milk)
(b)The temperature of the milk (49 degrees Celsius) after the milk is heated
(c)The beakers used

      (e) Hypotheses

The higher the pH of the liquid is, the more curds is present.
The higher the volume of acid, the more curd is present.

E.    Method – Description in detail of method or procedures (The following are important and key items that should be included when formulating ANY AND ALL research plans.)

(a) Equipment list:
  • Beakers 500 ml capacity (x3)
  • Beakers 250 ml capacity (x2)
  • Masking tape (x1 roll)
  • Pen or permanent marker (x2)
  • Glass rod (x1)
  • Cider vinegar (200ml)
  • Yuzu juice (200ml)
  • Apple juice (200ml)
  • Coca-Cola (200ml)
  • Aloe vera juice (200ml)
  • Red wine (200ml)
  • Full Cream Milk (4 cartons) (4ℓ)
  • Microwave (x1)
  • Laboratory thermometer (x1)
  • Plastic tray (x1)
  • Kitchen scale (x1) (accurate to 0.01 gram)
  • Paper towels (x1 roll)
  • pH sensor (x1)
  • Measuring cup (x1)
  • Sieve (x1)

(b) Diagrams
Screen Shot 2016-02-24 at 8.15.11 am.png

(c) Procedures: Detail all procedures and experimental design to be used for data collection

  1. Using the pH sensor, measure the pH of all acids and record them in the notebook.
  2. Using the masking tape and pen, label the three beakers: 1, 2, and 3.
  3. Use the measuring cup to add 25 ml of cider vinegar to the beaker labeled "1," 50 ml, to the beaker labeled "2," 100ml. to the beaker labeled "3,”.
  4. Heat 750ml of milk in a beaker in the microwave.
    1. The exact amount of time needed will depend on your microwave. Start by warming the milk at 50% power for five minutes. The 50% power will help you avoid scalding (burning) the milk.
    2. Check the milk with a thermometer to make sure it is 45°C. If it is not heated enough, put it back in the microwave for another two minutes at 50% power.
    3. Repeat this step until the milk is 45°C.
  5. Carefully pour 250ml of hot milk into each of the two beakers with cider vinegar in them. Write down the observations in a data table in the notebook. Observe if the milk has separated into white clumps (called curds).
  6. Mix each mug of hot milk and cider vinegar slowly for a few seconds, to maximise the amount of vinegar reacting with the milk.
  7. Once the milk and cider vinegar mixture has cooled a bit, carefully pour the mixture from beaker "1" into the sieve. If there are any curds, they will collect in the sieve. The leftover liquid will filter into the beaker.
  8. Rinse the curds in the cloth with tap water 3 times, each time letting the water flow through the cloth before doing it the next time.
  9. Over a sink, squeeze all the extra liquid out of the curds. Scrape the curds off of the cloth.
  10. Weigh the ball of casein plastic on a kitchen scale (0.01g) using the tray. Record the weight in the table.
    1. The amount of casein plastic each recipe makes is called the yield for that recipe. The more plastic, as measured by weight in this case, the greater the yield
  11. Repeat steps 7-12 for the other two beakers of milk and cider vinegar.
  12. Repeat steps 1-13 for the yuzu juice, apple juice, aloe vera juice, soda and wine.

d) Risk, Assessment and Management: Identify any potential risks and safety precautions to be taken.

As the experiment involves fragile and brittle equipment, there is a risk of breakage and cutting of the hands.
Wear gloves when carrying out the experiment. In case of breakage, the cut to the hands will be minimized.
As the experiments involve heating, there is a risk of scalding the hand accidently.
Use mittens or thongs when carrying out the experiment
The experiment involves the handling of acids, so there is a risk of irritation when comes in contact with skin.
Wear gloves and goggles while conducting the experiment.
The experiment involves many liquids and drinking any would result in contamination and/or poisoning.
Do not drink any liquid included in experiment.
Table 3: Risk Assessment and Management table

(e) Data Analysis: Describe the procedures you will use to analyze the data/results that answer research questions or hypotheses

1.    Tabulate the data and calculate the mass of the casein produced with each acidic liquid
2.    Plot a graph of the mass of the casein against the different acids in which it is made.
3.    From the graph, we can find out which pH level of acid will create more casein from the same amount of milk. (The aim)

Screen Shot 2016-03-01 at 11.50.43 am.png

F. Bibliography: List at least five (5) major sources (e.g. science journal articles, books, internet sites) from your literature review. If you plan to use vertebrate animals, one of these references must be an animal care reference. Choose the APA format and use it consistently to reference the literature used in the research plan. List your entries in alphabetical order for each type of source.

(a) Books
Scherer, R., & Salter, C. (1911). Casein, its preparation and technical utilisation. Retrieved January 26, 2016, from

(b) Journals
J., Stephenson. (1996). Casein. Casein. Retrieved from

(c) Websites
Wikipedia, Casein

Science Buddies, Making Plastic from Milk

(d) Videos
Making Casein from milk

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