Experiment to determine the amount of Casein in different samples of milk
Experiment to determine the amount of Casein in different samples of milk.docx (Size: 26.21 KB / Downloads: 199)
Milk is a complete diet as it contains proteins, carbohydrates, minerals, fats, vitamins and water in it. Casein is the major protein constituent of present in the milk and is a mixed phosphor-protein.
Casein has isoelectric pH of about 4.7 and can be easily separated around this pH. It readily dissolves in dilute acids and alkalis.
Casein is present in milk as calcium-caseinate in the form of micelles. These micelles have negative charge. On adding acids to milk the negative charges are neutralized.
Milk is the whit fluid produced by the female of warm-blooded animals for feeding her young ones. Animals that produce milk directly gives birth to their offspring are called mammals.
In mammals the blood is pumped from the heart to the mammary glands. The mammary glands are able to separate different substances from the blood and combine them to make milk.
Milk has been called as nature’s most perfect and complete food. It provides all the nutrients, which are required by the human babies and other young mammals need for the growth and development.
Value of milk as food
Cow’s milk contains about 87% of water and 13% of solids. These solids contain nutrients of milk.
Nutrients of milk
Our body needs five kinds of nutrients daily for our good health, growth, development, and replacement of worn out tissues. These nutrients are required by our body to get energy to perform various metabolic activities in daily life. These nutrients are:
These are the major source 0f energy for our body. Carbohydrates are also called Polyhydroxyl aldehyde or Polyhydroxyl ketone. Carbohydrates content of milk is mainly lactose of milk sugar. In addition to provide energy, lactose helps the body to absorb minerals, calcium, and phosphorus in milk. Our bones and teeth are largely consisting of these minerals. Lactose also gives sweetness to milk.
Like carbohydrates fats also provides energy. They also supply certain fatty acids that our body must have. Fat give milk its rich flavor. Milk fat contains vitamins and several other substances. One of these substances is carotene which our body converts into vitamin-A. Milk fat appears as tiny globules.
They help the body to grow and remain healthy. Calcium and phosphorus is the most important mineral of milk. In fact, milk is the chief food source of calcium. Other minerals in milk include potassium, odium, sulphur and small amount of aluminium, copper, iron, iodine, manganese and zinc.
Like minerals help the body and maintain it, they also supply energy. The protein contains all required amino acids for building blood and tissue. Only egg protein and the proteins in some meat have higher food value than milk proteins content of milk.
These are essential for growth maintaining tissue and prevention of such diseases night blindness, beriberi, scurvy and rickets due to deficiency of vitamin-A, vitamin-B, vitamin-C, and vitamin- D. Milk provides more vitamins and in larger amount then most of the other natural foods. Milk is an excellent source of vitamin-A and B2 and a good source of vitamin-B1. Other vitamins include C, K, E, B6, B12 and Niacin. Milk also has vitamin-D the quantity is very low. In some countries, diaries add rxtra vitamin to milk.
All mammals contain the same nutrients but these nutrients are not at all identical in kind or in quantity. Compared with cow’s milk, for example, the milk from a water buffalo has 3 times as much as protein but three quarters the amount of sugar. Human milk has fewer proteins and minerals than cow’s milk but contains 1.5 times more sugar.
In almost every country with dairy industry, whole milk is sold, as food must meet certain standards most countries insist that whole milk should contain at least 3.0% milk fat and up to 8.5% non fat milk solid. Some require a higher percentage of about 3.5% milk fat, 5.0% lactose, 3.5% proteins and 0.7% minerals. The percentage differs between individual cow breeds. The quantity and composition of milk also depends on what a cow feed and how the animal is cared.