FOOD COMMODITIES NTD 201 (3 UNITS)

1. FOOD COMMODITIES NTD 201 (3 UNITS) • Course requirements: • CAT: 30% Exam: 70% • Class attendance compulsory • *Contact Lecturer ahead of time if any cogent reason will keep you away from lectures. • Present medical reports if absence from lectures/CAT was due to ill health. Sanni, S. A. , PhD Department of Nutrition & Dietetics University of Agriculture Abeokuta

2. Synopsis • 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

3. 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.

4. Food Classification

5. 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.

6. Foods and Food tables

7. 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.

8. 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.

9. 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.

10. 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.

11. 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.

12. Structure of the maize kernel (caryopsis)

13. Essential Amino Acid Content of Cereal Proteins

14. 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:

15. contribute to the energy and nutrition requirements of more than 2 billion people; • are produced and consumed by many of the world’s poorest households; • are an important source of employment and income in rural, and often marginal, areas, especially for women, and • 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

17. Chemical Composition of some Tropical Roots and Tubers

18. 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 : • Those containing high protein and high oil content. • 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.

19. Composition of some Legumes

20. Composition of some Fruits

21. Composition of some Vegetables

22. Composition of Meat and Meat Products

23. % Composition of Raw Fish Flesh

24. 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.

25. 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.

26. 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