Saturday, June 9, 2012

FOOD COMPOSITION


FOOD COMPOSITION
Most food contain more than one nutrient. The nutrient contents of foods have been determined by analyzing these in the laboratory. The composition of over 650 Indian foods has been determined.
The food composition tables give the concentration of nutrients in 100 g of the edible portion of the food. Therefore it is important to know how much of the food purchased is edible. In some foods, such as milk, butter, sugar, the edible portion is 100 percent. In fruits and vegetables, it varies from 65 percent in bananas to 98 percent in tomatoes.
The values for nutrients given in food composition tables are averages of the results obtained by analyzing a large number of samples of each food. Therefore the figures in such tables give a fairly good idea of the composition of each food.
Foods are grouped in the food value tables, on the basis of the plant from which the food is derived, for example, seeds, roots, leaves, fruits, etc. Animal foods are grouped on the basis of species and the product used.
It is interesting to note that there are inherent similarities in the composition of foods in each group.  In the table 1.1 the composition of various foods has been presented to illustrate this  point. For example, the protein content of cereals varies from 7 to 12, and that of dals and legumes from 17 to 25 per cent. This information has important applications in practical usage of tables. It is possible to predict the overall nutrient content of combinations used, if we know the amounts of individual foods used. If the composition of a particular food is not found in the tables, you can roughly predict its nutrient combination, by knowing the group to which it belongs.
You may observe from Table 1.1, that cereals and dals do not contain vitamins A and C. Therefore you will realize how important it is to include vegetables and fruits, which are rich source of these two vitamins, in our daily menu of cereals and dal. Most of the vegetables and fruits, as you will observe from Table 1.1 , are low n calories. Oils, fats and sugars are mainly sources of calories. Thus you get an idea of the contribution of various foods by studying Table 1.1.



Table 1.1: Food Composition at a glance
( Approx, Group Values per 100 g E.P)
Foods
Moisture
Calories
Protein (g)
Vit.  A (mcg)
Vit. C
(mg)
Minerals and Vit. B-Comp.
Cereals-rice, Wheat, bajra, Jowar
10
340
7 to 12
---
---
Some
DAls, Legumes
10
340
17 to 25
---
---
Some
Milk
85
70
3
48
---
Some
Eggs
75
170
13
960
---
Some
Meat, fish, poultry
75
100-190
18
Some
---
Some
Leafy & Orange-yellow Vegetables & Fruits
90
20
2
1800
30
Some
Fruits-Vit. C - rich
85
50
1
Some
50
Some
Other Vegetables
90
30
2
Some
Some
Some
Other Fruits
85
50
1
Some
Some
Some
Roots & tubers
60-85
50-100
1
Some
Some
Some
Oils & Fats
0
900
--
750
---
---
Sugar, Jaggery
0
400
---
---
---
---

Most of analytical work on Indian foods was carried out in various laboratories under the auspices of Indian Council of Medical research (ICMR). A compilation of results is published as the Nutritive Value of Indian Council of Medical Research. A number of new varieties of food with high contents of certain nutrients, have been developed at research centers under the auspices of the Indian Council of Agricultural Research. You get a number of those foods in the market and use these in your dietary. The nutritive value of these new varieties of foods needs to be included in the book of Nutritive Value of Indian Foods. There are two International Food Value tables published by the Food & Agriculture Organization (FAO). It is good to remember that the nutritive value of natural foods does not vary a great for a particular variety of the same food from one country to another. But there is a great variation in the composition of prepared foods such as bread, biscuits, cakes, etc., due to variation in recipes and the basic ingredients used from one region to another.   
 

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