MILK AND MILK PRODUCTS
Milk is a creamy liquid produced from the mammary glands of all female mammals for feeding their young ones. Milk can be produced from cows, horses, goats, sheep etc. The commonly used worldwide is cow milk. It is one of the most valuable foods containing practically all foods substance. It is sometimes regarded as nature’s perfect food but this is only true for babies , the nutrients are not in the correct proportions for adults , the proportions of carbohydrate is too law and it also lacks iron and vitamin C . Milk is extremely valuable in the diet of invalids and convalescent on account of its food value. It is richly digested.
Table of Contents
NUTRITIVE VALUE OF MILK
The percentage nutrient composition is shown below.
Composition of whole milk
NUTRIENTS PERCENTAGE (%)
Milk, as can be seen from the composition above, has a good balance of carbohydrate, fat and protein. The carbohydrate in milk is called lactose. It is a disaccharide and is less sweet than the common sugar, sucrose. It is also less soluble than sucrose. The fat content of whole milk varies among individual cows. However, during processing in the industries, milk is blended and fat content controlled. The minimum standard for the fat content of whole milk in many countries is 3.25%.
Milk is a good source of high quality protein. The major protein in milk is casein. The second most important protein found in milk is albumin, while the protein globulin ranks third. It must be mentioned that the protein in milk is rich in all the essential amino acids. Whole milk is also rich in vitamins, both fat soluble and water soluble vitamins. Among the fat soluble vitamins, vitamin A is found in the highest quantity while vitamin D, E and K are present in small amounts. Milk is only a fair source of thiamine, but is a good source of riboflavin. Similarly, milk is a good source of some essential mineral elements such as calcium and phosphorus. It is however, low in iron.
TYPES OF MILK
- Fresh whole milk: This is the milk that is obtained directly from the cow in which none of the nutrients has been removed. It is therefore, very nutritious. The fresh whole milk can however, be subjected to other industrial processes in a bid to preserve and store it. For example, the milk can be heated for a short time (about 30 minutes) at a temperature below 1000 Such a heat treatment is known “pasteurization”. The aim of pasteurization is to kill all the harmful bacteria present in the milk. The milk can also be homogenised. Another processing that fresh milk can be subjected to is “sterilization”. In this process, the milk is subjected to a more severe heat treatment than pasteurization. The objective here is not only to kill the harmful bacteria, but all the micro-organisms present in the milk.
- Skimmed milk: Here the fat content has been removed. It is therefore made predominately of protein, carbohydrate, minerals and vitamins. Consequently, it has lower energy value than the whole milk.
- Dried or powdered milk: Over 90 % of the water content has been removed and it is then milled to powdered form. Both whole and skimmed milk can be processed into milk powder. When skimmed milk is used, it is known as dried skimmed milk.
- Evaporated milk: This is a whole milk from which about 60% of the water content has been removed. This is achieved by beating the milk in a vacuum. It is then homogenized, cooled, put into cans and sterilized by heat treatment.
- Condensed milk: This is evaporated milk to which a safe and suitable nutritive sweetener usually sugar has been added, so it is sweeter and thicker than evaporated milk. Because of the very high sugar content. It can keep longer than evaporated milk. When over 95 percent of the water content of condensed milk is removed, condensed dry milk is obtained.
- Yoghurt: this is obtained by allowing the milk to ferment for some time by some special type of bacteria. The resulting product usually has a characteristic ‘tangy’ taste. At local level, yoghurt is produced in a form known as Nono (Hausa).
- Cheese: the making of cheese is an ancient method of preserving milk. Cheese is usually produced by fermenting the whole milk by lactic acid forming bacteria followed by treating the product with an enzyme known as rennin. An example of a local cheese is Wara (Yoruba).
Types of Cheese
There are different types of cheese, these include:
- Hard cheese e.g. Cheddar, Cheshire, Parmesan.
- Semi-hard cheese e.g. Caerphilly, Wensleydale
- Blue-veined e.g. Irish Blue, Danish Blue
- Soft cheese e.g. Camembert
- Cheese spread e.g. Samsoe and Gouda.
USES OF YOGHURT
Uses of Milk Products
- It can be taken to occasion such as picnics, camping, caravanning where it can be served as desserts. It is also consumed in hot climates as a refreshing meal course.
- It can be served with pastry instead of cream
- It may be used with fruits and vegetable salad or added to the salad dressing.
- It can be added to dishes to improve their flavour e.g. to soup sauces and gravies.
USES OF CHEESE
- As main ingredients in dishes e. g. It can be used as substitute for meat in vegetarian dishes
- Acts as additional flavouring
- Can be consumed as snacks. e.g. with bread or biscuit
- Can be served plain at the end of lunch
- Can be used to supplement carbohydrate foods e.g. macaroni cheese, cheese pudding e.t.c.
Describe the pasteurisation and homogenisation of milk
Make a research to find out how local cheese [Wara] is prepared