ravi's chem file.pdf

  • View

  • Download

Embed Size (px)

Text of ravi's chem file.pdf


    I would like to express my sincere gratitude to my

    Chemistry mentor Miss Deepika Arora for their

    vital support, guidance and encouragement without

    which this project would not have come forth

    from my side.

    Special thanks of mine goes

    to my colleagues who helped me a lot in completing

    the project by giving interesting ideas, thoughts &

    made this project easy and accurate. I wish to

    thanks my parents for their undivided support &

    interest who inspired me & encouraged me to go

    my own way, without which I would be unable to

    complete my project. And at last by no means

    the least I would thank to God who made all the

    things possible.

    Ravi baghel












    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.

  • AIM To study the quantity of Casein in different

    samples of milk.


    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 natures 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 Cows 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 extra vitamin to milk.

    All mammals contain the same nutrients but these nutrients are

    not at all identical in kind or in quantity. Compared with cows

    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 cows 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.

    Milk is a complete diet as it contains in its Minerals,

    Vitamins Proteins, Carbohydrates, Fats And Water. Average

    composition of milk from different sources is given below:

    Source of Milk

    WATER (%)

    MINERAL (%)

    PROTEINS (%)

    FATS (%)


    COW 87.1 0.7 3.9 3.9 4.9

    HUMAN 87.4 0.2 4.0 4.0 4.9

    GOAT 87.0 0.7 4.2 4.2 4.8

    SHEEP 82.6 0.9 5.5 6.5 4.5

    Caesin is a major protein constituent in milk & is a mixed

    phosphor-protein. Casein has isoelectric pH of about 4.7 and

    can be easily separated around this isoelectric pH. It readily

  • dissolves in dilute acids and alkalies. Casein is present in milk

    as calcium caseinate in the form of micelles.


    > Beakers (250 ml)

    > Filter-paper

    > Glass rod

    > Weight box

    > Filtration flask

    > Buchner funnel

    > Test tubes

    > Porcelain dish

    > Different samples of milk

    > 1 % acetic acid solution

    > Ammonium sulphate solution

  • THEORY Natural milk is an opaque white fluid Secreted by the

    mammary glands of Female mammal . The main

    constituents of natural milk are Protein, Carbohydrate,

    Mineral Vitamins, Fats and Water and is a complete

    balanced diet. Fresh milk is sweetish in taste. However ,

    when it is kept for long time at a temperature of 5 degree it

    become sour because of bacteria present in air. These bacteria

    convert lactose of milk into lactic acid which is sour in

    taste. In acidic condition casein of milk starts separating

    out as a precipitate. When the acidity in milk is sufficient

    and temperature is around 36 degree, it forms semi-solid

    mass, called curd. Casein is present in milk as calcium

    caseinate in the form of micelles. These micelles have

    negative charge and on adding acid to milk, the negative

    charges are neutralized.


    Casein (/kes.n/ or /kesin/, from Latin caseus,

    "cheese") is the name for a family of related phosphoproteins

    (S1, S2, , ). These proteins are commonly found in

  • mammalian milk, making up 80% of the proteins in cow

    milk and between 20% and 45% of the proteins in human

    milk. Casein has a wide variety of uses, from being a major

    component of cheese, to use as a food additive, to a binder for

    safety matches. As a food source, casein supplies amino

    acids, carbohydrates, and the two inorganic elements

    calcium and phosphorus.


    Casein contains a fairly high number of proline residues,

    which do not interact. There are also no disulfide bridges. As

    a result, it has relatively little tertiary structure. It is

    relatively hydrophobic, making it poorly soluble in water. It

    is found in milk as a suspension of particles called "casein

    micelles" which show only limited resemblance with

    surfactant-type micellae in a sense that the hydrophilic

    parts reside at the surface and they are spherical. However,

    in sharp contrast to surfactant micelles, the interior of a

    casein micelle is highly hydrated. The caseins in the

    micelles are held together by calcium ions and hydrophobic

    interactions. Any of several molecular models could account

    for the special conformation of casein in the micelles. One of

  • them proposes the micellar nucleus is formed by several

    submicelles, the periphery consisting of microvellosities of

    -casein. Anoher model suggests the nucleus is formed by

    casein-interlinked fibrils. Finally, the most recent model.

    proposes a double link among the caseins for gelling to take

    place. All three models consider micelles as colloidal

    particles formed by casein aggregates wrapped up in soluble

    -casein molecules.

    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