FOOD COMMODITIES
NTD 201
(3 UNITS)
Sanni, S. A. , PhD
Department of Nutrition & Dietetics
University of Agriculture
Abeokuta
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Course requirements:
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CAT: 30%
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Class attendance compulsory
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*Contact Lecturer ahead of time if any cogent reason will keep you away from lectures.
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Present medical reports if absence from lectures/CAT was due to ill health.
Exam: 70%
Synopsis
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Food Classification
Market Surveys
Food Selection & purchasing
Uses of Foods
Foods and Food tables
Cereals,
Starches & starchy foods, Sugars,
Pulses, nut and seeds
Vegetables and fruit
Meat, fish etc.
Infective agents in food
Natural food toxins
Food Defined
 Food is any substance that is consumed to provide
nutritional support for the body, possibly to the point
of excess.
 It is usually of plant or animal origin, and contains
essential nutrients, such as carbohydrates, fats,
proteins, vitamins, or minerals.
 The substance is ingested by an organism and
assimilated by the organism's cells in an effort to
produce energy, maintain life, and/or stimulate
growth.
Food Classification
Food Selection & purchasing
 The types of food you select depends on:
 the money you have
 your nutritional needs and
 the effect of advertisements
 Now let us examine each of these factors and see how they influence our selection or choice
of food!
Nutritional needs
 Your food choice will also depend on your need for food. Everyone has a biological need for
food. It is essential for life without food one becomes weak and ill. People vary in the amount
of food they need for reasons like health, age and activity.
 Your choice of food will therefore depend on each of these factors. Your nutrition knowledge
helps you to choose food that provides the necessary nutrients to meet your needs.
 Food Purchasing
 Food purchasing can be a boring or interesting adventure depending on one’s approach to it.
To make food purchasing interesting you have to know much about the market place and
ways in which you can make the most out of your food budget.
 Now let us look at some of the things you can do to avoid waste of your time and money when
purchasing food.
 First of all you need to know the factors that determine the cost of the things you want to
purchase.
Foods and Food tables
Foods Rich in
-------------------Carbohydrates------------------- Fats
Proteids
Chocolate
Honey
Vegetables -
Butter
Cheese
Vegetables -
Fruits -
Nuts -
Asparagus
Cheese
Eggs
Asparagus
Dates
Chestnuts
Bananas
Chocolate
Fish
Beet-tops
Figs
Peanuts
Beets
Cream
Legumes -
Cabbage
Grapes
Pignolia or
Cabbage
Nuts -
Beans - dried
Carrots
Persimmons
pine nuts
Carrots
Almonds
Lentils - dried
. Celery
Raisins
Sirups
Celery
Brazil-nuts
Peas - dried
Dandelion
Grains -
Sugar
Lettuce
Cocoanuts
Milk
Green peas
Barley
Tapioca
Onions
Hickory-
Nuts -
Lettuce
Corn
Parsnips
nuts
Peanuts
Onions
Oats
Potatoes -
Peanuts
Pignolia or
Radish-tops
Rice
sweet
Pecans
pine nuts
Romaine
Rye
Potatoes -
Pignolia or
Poultry
Spinach
Wheat
white
pine nuts
Vegetables -
String beans
Pumpkin
Walnuts
Cabbage
Turnip-tops
Spinach
Oils -
Lettuce
Watercress
Squash
Cottonseed
Onions
Wheat bran
Turnips
Nut-oil
Spinach
Olive-oil
Turnips
Wheat bran
Mineral Salts
CEREALS
Cereals are the edible seeds or grains of the grass family.
There are many different types of cereal grains, each having
unique properties.
Most cereals are processed to form other foods or ingredients.
Cereals and cereal products are an important source of energy,
carbohydrate, protein and fibre. They also contain a range of
micronutrients such as vitamin E, some of the B vitamins,
sodium, magnesium and zinc. Wheat and rice are the most
important cereal crops world-wide as they account for over 50%
of the world’s cereal production.
TYPES OF CEREALS
Wheat: is usually ground to flour which is used to produce a wide range of
products. The type of flour produced differs according to the rate of
extraction. Couscous and cracked wheat or bulgur is also made from wheat.
Wheat can be fermented to make beer.
Maize: (or corn) may be processed to make many different ingredients (e.g.
high fructose corn syrup which can be used as an alternative to sucrose
derived from sugar cane and sugar beet) and food products. It may be milled
in a similar process to wheat. Its germ is rich in oil, and can be refined to
produce corn oil.
Barley: is mainly sold as pearl barley, which is the whole grain with its husk
removed. It is also used in bread (as flour) and ground as porridge in some
countries.
Rice: brown rice has its outer husk removed, and white rice is milled and
polished further to remove the bran and germ. There are many different
types of rice, categorized by size, shape and the region where they are grown.
Rice can be ground to make flour and is used to make Japanese rice wine
(saké).
Rye: contains little gluten, so produces breads with low volume and a dense
texture, although in Russia, Poland, Germany and Scandinavian countries it
is the major bread grain. Rye is also used to produce crisp bread and alcohol.
Oats: are rolled rather than crushed during processing. Coarse, medium
and fine grades of oatmeal are available and are used for porridge and
oatcakes, while rolled oats are used for porridge, and oat flour is used for
baby foods and for ready-to-eat (RTE) breakfast cereals.
Millet: is the name used for a number of different small-grained cereal
grasses, e.g. pearl, finger (or ragi), proso and foxtail millet. These crops are
important in parts of Africa and Asia.
Sorghum: (also known as great millet, guinea corn, kafir corn, jowar and
kaoling in different parts of the world) is a staple food in many parts of
Africa, Asia and parts of the Middle East. It is also used as animal feed in
many other countries.
NUTRITIONAL VALUE OF CEREALS AND CEREAL PRODUCTS
Cereals and cereal products are an important source of energy, carbohydrate, protein
and fibre.
They also contain a range of micronutrients such as vitamin E, some of the B
vitamins, sodium, magnesium and zinc. Because of the fortification of some cereal
products they also contribute significant amounts of calcium and iron.
There is evidence to suggest that regular consumption of cereals, specifically whole
grains, may have a role in the prevention of chronic diseases. The strength of
evidence varies and although cause and effect has not currently been established,
people who consume diets rich in whole grain cereals seem to have a lower incidence
of many chronic diseases, e.g. coronary heart disease and type 2 diabetes.
It remains to be established whether this is a direct effect, or whether whole grain
consumption is merely a marker of a healthy lifestyle or some other factor.
Structure of the maize kernel (caryopsis)
Essential Amino Acid Content of
Cereal Proteins
Essential Amino
Acids
Percentage content
Rice
Corn
Wheat
Arginine
8.40
9.36
24.06
Histidine
2.60
0.75
7.89
Isoleucine
4.50
0.80
0.00
Leucine
8.40
31.22
33.91
Lysine
3.50
6.71
5.88
Methionine
2.50
2.35
4.84
Phenylalanine
4.50
9.34
8.40
Threonine
3.90
2.90
2.00
Tryptophan
1.20
2.07
8.14
Valine
6.50
1.88
3.85
ROOTS AND TUBERS
Roots are plant materials which edible portions grows under the soil but the stem
serve as planting materials, while tubers are thick parts or swollen parts of an
underground stem bearing small buds from which new plants can be formed. Roots
and tubers belong to the class of foods that basically provide energy in the human
diet in the form of carbohydrates. The principal root and tuber crops of the tropics
are cassava (Manihot esculenta Crantz), yam (Dioscorea spp.), sweet potato (Ipomoea
batatas L.), potato (Solanum spp.) and edible aroids (Colocasia spp. and Xanthosoma
sagittifolium). They are widely grown and consumed as subsistence staples in many
parts of Africa, Latin America, the Pacific Islands and Asia. The increased use of
major roots and tubers – cassava, potato, sweet potato, and yam, for food and
livestock feed in developing countries will have wide-ranging effects on global
public- and private-sector policies and investments. Roots and tubers will continue
to play a significant role in developing-country food systems because they:
a. contribute to the energy and nutrition requirements of more than 2
billion people;
b. are produced and consumed by many of the world’s poorest
households;
c. are an important source of employment and income in rural, and
often marginal, areas, especially for women, and
d. d.adapt to a wide range of uses, from food-security crops to cash
crops, raw material for industrial uses, and from fresh to high-end
processed products.
Roots and tubers together constitute a significant share of the total volume
and value of horticultural crops worldwide. These commodities are
particularly important as a source of food, employment, and income in
developing countries where the bulk of the world's producers, processors,
and consumers reside. In this new millennium, roots and tubers will play
Cereals and oil seeds
Roots and tubers
1.Low moisture content, typically 10% to
15%
High moisture content, typically 70% to
80%
2. Small unit size, typically less than 1
gram
Large unit size, typically 100 grams to 15
kg
3. Very low respiration rate with very low
generation of heat. Heat production is
typically 0.05 megajoule/ton/day for dry
grain
4. Hard texture
High respiration rate. Heat production is
typically 0.5 to 10 megajoules/ton/day at
0°C to 5 to 70 megajoules/ton/day at
20ºC
Soft texture, easily bruised
5. Stable, natural shelf life is several
years
Perishable, natural shelf life is a few days
to few months
6. Losses usually caused by moulds,
insects and rodents
Losses usually caused by rotting
(bacteria and fungi), senescence,
sprouting and bruising
Chemical Composition of some Tropical
Roots and Tubers
Commo Dry
Crude Ether Total
dity
Phosphorus Fe
Matters Protein extract ash
(g)
(g)
(g)
(g)
(mg)
Energy Ascorbic Calcium
(cals)
acid
(mg)
(mg)
(mg)
Cassava
31.94 2.71
0.53
2.66
390.0
35.0
10.0
35.0
0.50
Yam
26.17 5.87
0.46
4.30
385.9
17.0
18.9
40.7
0.48
Cocoya
m
(Taro)
26.5
2
8.66
0.71
4.83
376.4
14.0
24.0
53.6
0.72
Cocoya
24.8
m
9
(Tannia)
7.85
0.70
5.22
382.6
10.0
6.0
360.0
0.70
Sweet
Potato
5.36
0.33
3.15
391.0
26.2
16.6
31.0
0.83
28.0
8
Pulses (Legumes)
Legumes are widely distributed world- wide and generally referred to as pulses. Every zone of the world has
some legumes peculiar to them.
For example, in France, groundnuts are found, in South America, lima and runner beans, in the United
States, soya beans and in Africa, cowpeas, bambara nut, broad beans, in India, lentils and chick peas etc.
The fruit is a pod containing seeds ranging generally from 2-10 seeds. There are two main types of legumes,
viz :
I.
Those containing high protein and high oil content.
II.
Those containing moderate protein and low oil content.
Examples of the first group include soya bean, groundnut, lupin and winged beans. The protein content is as
high as 35% while oil content vary from 15 - 45%.
Examples of the second group include cowpea, gram, pea, bambara groundnut, lentil and the different
varieties of the phaseolus group. The protein content is in the range of 25- 30% while the oil content is
less than 5%.
Legumes are generally high in B vitamins but low in sulphur containing amino acids, methionine and cystine.
They have high content of lysine which makes legumes a good complement to cereals (cereals are low
in lysine but high in methionine).
Legumes have some nutritional disadvantages apart from being deficient in methionine and cystine. These
are of low digestibility and the consumption of high proportion of legumes in the diet can cause
flatulence. Some legumes contain toxic substances which interfere with normal enzymic reactions.
Composition of some Legumes
Legumes
Moisture
(g)
Energy
(KJ)
Protein
(g)
Fat
(g)
Total
Carbohydrates(g)
Bambara groundnut
10
1550
20
6
60
Black eye Beans(raw)
13
1360
23
1.5
58
(Decorticated)
30
1080
20
1.2
44
(Moi- moi)
70
500
7
2
20
(Akara)
60
920
9
15
14
Black gram (Urad
dahl)
10
1450
24
1.5
60
Chick pea (Bengal
gram)
11
1360
20
5.6
60
Humous (Chick pea
paste)
60
770
8
13
11
Groundnut (Dry)
5
2570
26
48
20
Lentil (Masar dahl
12
1300
20
0.6
65
Lima (Butter) Bean
12
1162
20
1.5
58
Mung Bean
12
980
22
1.0
35
(Sprouts)
90
146
3.8
0.2
6
Pea
78
280
5.8
0.4
11
Soya Bean
10
1700
40
20
20
Winged Bean
10
1700
33
17
37
Composition of some Fruits
Comm
odity
Wate
r
(%)
Energ
y
(cal)
Protei
n
(%)
Fat
(%)
Carbo Ascor
hydra bic
te (%) acid
(%)
Calci
um
(%)
Phos
phor
us
(mg)
Vit. A
(i.u)
Banana 75
86
1.1
0.2
24
10
8
26
190
Pineap
ple
85
65
0.4
0.4
15
110
20
11
30
Mango
83
63
0.6
0.1
15
30
10
10
180
Guava
80
58
1.0
0.4
13
200
15
33
200
Orange 86
49
1.0
0.2
12
50
41
20
200
Lemon
58
1.0
0.9
11
43
40
22
-
Cashew 85
apple
-
0.7
-
13
250
10
-
150
Pawpa
w-ripe
40
0.5
0.6
10
110
16
8
2200
Fruits
85
81
Composition of some Vegetables
Comm
odity
Wate
r
(%)
Energ
y
(cal)
Protei
n
(%)
Fat
(%)
Carbo Ascor
hydrat bic
e (%)
acid
(%)
Calci
um
(%)
Phosp Vit. A
horus (i.u)
(mg)
Onions
89
38
1.5
0.1
9
10
27
56
40
Carrot
88
42
1.1
0.2
10
51
37
36
11000
Spinach 91
26
3.2
0.3
5
51
93
51
8100
Cabbag
e
92
24
1.3
0.2
4
47
49
29
130
Pepper
92
22
1.2
0.2
4
125
9
22
420
Tomato 93
22
1.1
0.2
5
30
13
27
190
Composition of Meat and Meat Products
Type
% Composition of Edible Portion
Water
Protein
Fat
Ash
Carbohydrate
Beef (medium fat)
60.0
17.5
22.0
0.9
-
Veal (medium fat)
66.0
18.8
14.0
1.0
-
Pork (medium fat)
42.0
11.9
45.0
0.6
-
Lamb (medium fat)
56.0
15.7
27.7
0.8
-
Chicken
66.0
20.2
12.6
1.0
-
Duck
52.8
16.2
30.0
1.0
-
Turkey
58.3
20.1
20.2
1.0
-
Fish (fillet non fat)
81.8
16.4
0.5
1.3
-
Fatty fish fillet
68.8
20.0
10.0
1.4
-
Crustaceans
79.3
14.6
1.7
1.8
2.6
Dried fish
4.0
60.0
21.0
15.0
-
Milk (cow)
87.3
3.5
3.5
0.7
5.0
Cheese (hard)
37.0
25.0
31.0
5.0
2.0
% Composition of Raw Fish Flesh
Lean
Fatty
Water
80
60-80
Protein
16-18
16-18
Lipids
0.5-2.0
5-20
Extractives(salts glycogen, amino acids 0.5-2.0
0.5-2.0
Mineral content
1.0-1.5
Lean: cod, haddock, whiting, rockfish,
sole
Fatty: Salmon, mackerel, trout,
butterfish
1.0-1.5
Infective and Toxic Agents in Foods
 There are more than 200 known diseases that can be
transmitted through food, however, and the known
causes of food poisoning include infective agents and
toxic agents.
 Infective agents include viruses, bacteria, and
parasites.
 Toxic agents include poisonous mushrooms,
improperly prepared exotic foods (such as barracuda),
or pesticides on fruits and vegetables.
Sources of Food Contamination
 Food usually becomes contaminated with these agents
from poor sanitation or preparation. Food handlers
who do not wash their hands after using the bathroom
or have infections themselves often cause
contamination.
 Improperly packaged food stored at the wrong
temperature also promotes contamination.
 Three of the most important causes of food poisoning
are the salmonella, clostridium botulinum and
staphylococcal organisms.
Further Readings
 Collingham, E. M. The Taste of War: World War Two
and the Battle for Food (2011)
 Marion Nestle: Food Politics: How the Food Industry
Influences Nutrition and Health, University Presses of
California, revised and expanded edition 2007, ISBN
0520254031
 Katz, Solomon. The Encyclopedia of Food and Culture,
(Scribner, 2003)
 http://en.wikipedia.org/wiki/Food
 http://www.healthscout.com/ency/68/676/main.html