0
First you need to understand what milk is, other than a just a white liquid you get from mammary glands. Milk is an emulsion of fat, water, lactose (a type of sugar) and a mixture of proteins (loads of other stuff, but these are what we will talk about).
The small fat globules are surrounded by a skin of phospholipids and proteins, which are chemicals that help them stay as small globules in the mix, rather than cumping together into a big pat of butter. If you beat the milk, that is exactly what happens - and is how you make butter from milk.
The water in the milk contains soluble proteins, which wander around by themselves in the liquid, and proteins which have one end which likes water, and one end which doesn't. Think of a match - a red head on one end, with a tail of wood trailing behind. In order for the "water hating" ends of the protein (the wood of the match) to stay away from the water they are floating in, these proteins arange themselves into globes called micelles. Kind of like a circle of cows in a field standing in a protective circle, with all of the tails in the centre and a circle of heads looking outwards.
The proteins that do this are called caseins, there are four different types and they make up about 80% of the weight of the total protein in the milk. The outer layer of these micelles is made up of a type of casein known as kappa-casein, and the kappa casein reaches out a bit into the surrounding liquid. Under an electron microscope, each ball looks a bit like a little polystyrene ball (like you get in bean bags and the like), with a bit of a lumpy surface. The kappa-casein has a negative charge, and as like charges repel, all of the micelles stay away from each other - which keeps them in solution.
An acid is any chemical which loves to give (positively charged) protons away, and the stronger the acid, the stronger the tendency to force protons onto other chemicals (which usually breaks them down into simpler structures - this is the iconic "fizzing" you see in Hollywood movies involving acids.)
As you add acid to milk, say by pouring in lemon juice, or by letting bacteria turn the milk sugar lactose into lactic acid, more and more positively charged protons are given to the negatively charged kappa-casein, the kappa-casein loses its charge and so the casein micelles begin to clump together. Eventually the clumps become big enough to see - which are the lumps we call curds, and the process is called curdling. Good if you want to collect the curds to make cheese. Bad if you want a smooth drink or sauce!
If you heat the milk up to at least 85 degrees C before you add the acid, then the kappa-casein reacts with the soluble protein (called a whey protein, becasue it doesn't mind floating around by itself in the watery whey) b-lacto- globulin. The result is a complex which makes the casein micelle surface markedly coarser, so if you now add acid (usually by allowing a "good tasting" bacteria to turn the lactose into lactic acid) the casein micelles clump into an open spongy gell. This sponge soaks up the liquid, and you end up with Yoghurt. Yoghurt is much more stable in cooking and acepting acid for this reason.
What else can I help you with?
Why does vinegar separate milk?
Vinegar makes milk curdle and the nature of vinegar is to not mix.
Does tabasco sauce curdle milk?
Tabasco contains quite a bit of vinegar so yes it will curdle milk due to the vinegar.
How can cheese be made using milk and vinegar?
Cheese can be made using milk and vinegar by heating the milk, adding vinegar to curdle it, straining the curds from the whey, and pressing the curds to form cheese.
How do you explain what happened to the milk if the vinegar spilled and give a simple experiment to explain happened?
When vinegar is added to milk, a chemical reaction occurs causing the milk to curdle and form lumps. This is due to the acid in vinegar causing the proteins in the milk to denature and clump together, separating into curds (solid) and whey (liquid). To show this, you can pour vinegar into a beaker of milk and observe how the milk starts to curdle and separate into curds and whey.
Is it camels milk that does not curdle?
Yes, Camels milk does not curdle
Does adding vinegar to milk saw that milk so that the milk will curdle cause a physical change wilco don't cause a physical change?
This is a chemical change.
How to curdle milk effectively for making cheese at home?
To curdle milk effectively for making cheese at home, you can add an acid like lemon juice or vinegar to warm milk and let it sit until curds form. Then, strain the curds through a cheesecloth to separate them from the whey.
How do you make plastic from milk?
Its relatively simple. The plastic is called casein. Basically all you need to do is curdle the milk using vinegar. See the link for more detail.
What makes milk curdle besides acidity and temperature?
Bacteria in the milk can also cause it to curdle.
Do milk and vinegar create a chemical reaction?
Yes, when you add an acid, like vinegar, to milk a chemical reaction occurs. The acid causes milk to curdle. In fact, by adding vinegar to milk you can make cheese! http://www.wikihow.com/Make-Cheese-at-Home
What happens if you put vinegar in cream?
Vinegar will curdle cream or milk. If you need buttermilk for a cake recipe and have none, you can add a couple of teaspoons of white or cider vinegar per cup of milk, let it stand for about 15 minutes and it's ready to add to your batter.
Do you have to have shortening and buttermilk to make biscuits?
The shortening can be replaced with butter of margarine. One can replace buttermilk with regular milk or you may add a teaspoon of vinegar to the milk which will make it curdle.
