Topics Understanding Ingredients Cereals Introduction Nutritive Value of Cereals Choice and Storage of Cereals Types of Cereals Food and Nutrition Labelling of Cereals 2 Introduction Introduction Cereal is the edible seeds of various plants belonging to the grass family The six major types of cereals are rice, wheat, maize, oat, barley and rye Cereals have been an essential part of the human diet since the beginnings of agriculture in the first millennium B.C. 3 4 1
Introduction World s cereal production expressed as percentage Data: Food and Agriculture Organization of the United Nation (FAOSTAT) data corresponding to 2010 They can be grown in a large part of the world and provide the staple food for most of mankind Cereal consumption has declined in industrial countries over the last century But remain the most important crop in the third world, where it is the major source of food energy up to 90% of protein intake, compared to a mere 25% in industrialized countries Barley, 5% Wheat, 27% Sorghum, 2% Others, 3% Rice, 28% Corn, 35% 5 6 Most cereals belong to the family of grasses Most grains share a common structure The proportions constituted by the different parts vary from one cereal to another The cereal grain (caryopsis) consists of three main parts: Outer layer (the bran) Endosperm (or kernel) The germ 7 8 2
Endosperm (or kernel) Germ The seed is enclosed in an outer shell, or hull, that cannot be assimilated by the human digestive system Therefore, the grains must be hulled to make them edible Outer layer (the bran) Bran: coarse outer protective coating Enclosing the kernel Made up of several fibrous layers Included in wholemeal flour Rich in vitamins (especially vitamin B complex) and minerals (such as calcium, iron, and phosphorous) Plays an important role in the functioning of the gastrointestinal system by helping to prevent constipation A wheat kernel 9 10 Endosperm (kernel): the starchy store of food The largest part of the grain Composed mainly of starch, a complex carbohydrate that is absorbed slowly by the body, producing a long-lasting feeling of satiety Germ: the plant embryo Located in the lower end of the grain Contains the seed of a new plant Small in size Often separated from flour in milling (included only in wholemeal flour) Can be processed into oil of cereals, e.g. corn oil Has the highest concentration of nutritional elements, including various vitamins, minerals, proteins, and also a high level of fat, which makes it perishable 11 12 3
Nutritive Value of Cereals Nutritive Value of Cereals Different parts in a cereal grain provide different nutrient profiles: Bran provides: Vitamin B complex Minerals such as calcium, iron, and phosphorous Dietary fibre Endosperm provides: Complex carbohydrate Plant proteins (plant proteins in cereal are low biological value proteins) Germ provides: Fat Plant proteins (plant proteins in cereal are low biological value proteins) Vitamin B complex Minerals such as iron 13 14 Choice and Storage of Cereals Choice and Storage of Cereals Choose cereals which are well-packed, dry and firm, without an unpleasant smell and weevils Best kept in airtight containers in a cool dry place Check the expiry date of the cereal products and use accordingly 15 16 4
Choice and Storage of Cereals Choosing rice Note the type of rice need Check the expiry date Should be dry and firm Should not contain sand nor weevil Storing rice Cover rice and store in a cool, dry place Use rice according to its expiry date Cover and store cooked rice in the refrigerator away from strong-smelling foods Choice and Storage of Cereals Choosing flour Note the type of flour need Check the expiry date Buy in the amount needed as flour cannot be kept long Storing flour Keep in air-tight containers Store in a cool, dry place Use flour according to its expiry date 17 18 Types of Cereals Types of Cereals Common cereal crops Wheat Rice Barley Corn or maize Millet Sorghum Oat Rye Wild rice Spelt Buckwheat Quinoa Amaranth Pseudo-cereals They are pseudocereals because they do not belong to the grass family. 19 20 5
World s cereal used as food expressed as percentage Data: Food and Agriculture Organization of the United Nation (FAOSTAT) data, 2013 Types of Rice Wheat and products, 45% Cereals, Other, 1% Rye and products, 1% Barley and products, 1% Rice (Milled Equivalent), 37% Maize and products, 12% Sorghum and products, Millet and products, 2% 2% In over 8,000 varieties, rice can be classified according to grain length and texture They are generally divided into short grain (or round grain), medium grain, and long grain types Short grain rice or round grain rice ( 粳米 ) measures 4 to 5 millimeters in length and 2.5 millimeters in width; its higher starch content makes it stickier when cooked Medium grain rice ( 秈米 )(5 to 6 millimeters long) is slightly shorter and plumper than long grain rice, these varieties remain firm and light when cooked but tend to stick when cooled Long grain rice (6 millimeters and over) is light, and the grains remain separate when cooked; however this rice can become sticky if it is overcooked or stirred too frequently during cooking 21 22 Types of Rice The market offers several kinds of rice with different kinds of textures: Brown rice is the whole grain with the fibrous inedible outer husk removed. Brown rice is the most nutritious form of rice; its nutty flavour is stronger than that of white rice. White rice has been hulled and polished, stripping it of a significant proportion of its nutrients. Compared to brown rice, it is much lower in niacin, thiamine, magnesium, zinc, iron, and fibre. Arborio rice is a classic round white rice that is the essential element in Italian dish. It is considered to be one of the finest types of rice. Glutinous rice has a white and opaque appearance. The starch of glutinous rice consists almost entirely of amylopectin. It has a tendency to stick together after cooking. Wheat kernels Storage Cleaning Milling Storage of flour Dispatch Wheat is commonly milled into wheat flour Three basic flour categories: White flour: usually 75% of the whole wheat grain Wholemeal flour: 100% made from the whole wheat grain with nothing added or taken away Brown flour: usually contains about 85% of the original grain 23 A simplified flow-chart of wheat milling 24 6
Type of wheat flour 2/6/2018 Two flour categories are commonly used: White flour Bran, germ, fat and some of the minerals are removed White in appearance Fine and smooth in texture Wholemeal flour The husk is removed The bran, germ and endosperm are kept Contains more nutrients than white flour Light brown / dark brown in colour Rough in texture Wheat protein Wheat proteins account for about 10 15% of the grain dry weight Four major types of protein: Albumins 20% of the endosperm protein, important in metabolism Globulins Gliadins 80% of the endosperm protein, gluten protein Glutenins The protein content is linked to the compactness of the gluten network Flours are subdivided according to their end-use: Strong flours used in bread baking Medium flours, all-purpose Weak flours used in making cake and biscuit 25 26 Wheat protein (cont d) Gluten is the protein found in wheat flour It becomes sticky and elastic when mixed with water White flour Strong flour - High protein content - 12-14% gluten content - Mainly for making bread In cooking flour mixture, the gluten helps form its shape and texture The amount of gluten in different types of flour varies Plain flour - Also called all-purpose flour - 10-12% gluten content - Suitable for a variety of uses Wholemeal flour Weak flour - Lower protein content - 8-10% gluten content - Suitable for making cakes and biscuit Self-raising flour - Raising agent added - 10% gluten content - Suitable for sponge cake and scones 27 28 7
Wheat flour is low in fat It provides protein, a variety of vitamins, particularly Vitamin B complex, and a range of minerals Wholemeal flour contains more fibre, vitamin B and fat than white flour Comparison of Nutrient between White Flour and Wholemeal flour Wheat flour, white, allpurpose, unenriched (Value per 100 g) Wheat flour, whole-grain Energy (kcal) 364 340 Protein (g) 10.33 13.21 Total lipid (g) 0.98 2.50 Carbohydrate (g) 76.31 71.97 Total dietary fibre (g) 2.7 10.7 Calcium (mg) 15 34 Iron (mg) 1.17 3.60 Phosphorous (mg) 108 357 Thiamin (mg) 0.120 0.502 Riboflavin (mg) 0.040 0.165 Niacin (mg) 1.250 4.957 Vitamin B-6 (mg) 0.044 0.407 29 Source: Food Composition Databases, Agricultural Research Service, United States Department of Agriculture, May 2016, ndb.nal.usda.gov/ndb/search/list. 30 Other Types of Flours Flour and their cereal sources: Wheat White flour Wholemeal flour Tang flour Durum wheat Semolina Rice Rice flour Glutinous rice flour Maize Cornflour Other Types of Flours Tang flour Milled from the endosperm with the gluten removed Flour mixture made with tang flour looks clear when cooked Semolina Coarse middlings from other varieties of wheat durum Create soft doughs, easy to shape into pasta The dough is relatively plastic, contrasting with the strong elastic doughs obtained from bread flours Commercially produced dry pasta is made almost exclusively from durum semolina Cornflour Also called corn starch Used to thicken sauces 31 32 8
Other Types of Flours Rice flour Used in some Chinese pastries, dim sum and rice noodles Glutinous rice flour Made from glutinous rice Contains almost 100% amylopectin Very sticky Used in making glutinous rice balls and other Asian cuisines Uses of Cereals in Cooking / Diet 33 34 Some cereals are eaten as they are, for example: Rice Maize Most of the cereals are processed and used to produce a range of products, for example: Wheat Oats Wheat Breakfast cereals Bread and cakes Pasta and noodles Pizza Rice Steamed rice Congee Dim sum Rice cakes and desserts (e.g. Mango with Glutinous Rice) Rice noodles Breakfast cereals, e.g. rice crispies Rice wine Maize Tortilla Cornflour Corn oil Cornflakes Popcorn 35 36 9
Product from wheat flour Oat Biscuits Oatmeal Barley Barley drink Barley in soup Rye Rye bread Rye beer Wheat flour may be mixed with water to form a dough The dough is further processed into different shapes to form noodles, pasta and ready-made wrappings Fresh noodles and ready-made wrappings should be stored in refrigerators and used within 2-3 days Store dry noodles and pasta in air-tight container, keep in a cool, dry place Store frozen spring roll wrappings in the freezer 37 38 Noodles Noodles are a popular form of pasta They are made from a paste of flour and water The flour may be made from wheat or rice Sometimes, egg or shrimp roe is added Noodles are long and thin; they come in different shapes They may be very fine, like vermicelli, or broad and flat Noodles (cont d) Noodles may be eaten as a snack or as part of a main meal Instant noodles are pre-cooked and may be quickly reheated Like rice, noodles form the starchy, energy-giving part of a meal Noodles may be cooked: by boiling, e.g. plain boiled noodles by frying, e.g. fried rice noodles with beef by stewing, e.g. stewed noodles with pork and mushrooms in soup 39 40 10
Food and Nutrition Labelling of Cereals Food and Nutrition Labelling of Cereals Labelling of cereals is controlled in Hong Kong legislation: List of ingredients Prepackaged food shall be legibly marked or labelled with a list of ingredients List of allergenic substance Cereals containing gluten (namely wheat, rye, barley, oats, spelt, their hybridized strains and their products) is an allergenic substance, the name shall be specified in the list of ingredients Appropriate durability indication Indication of best before or use by date 41 42 Food and Nutrition Labelling of Cereals Labelling of cereals is controlled in Hong Kong legislation: Nutrition labelling Prepackaged food shall be marked or labelled with its energy value and nutrient content Nutrition claim If any nutrition claim is made on the food label or in any advertisement, the nutrient in concern shall be marked or labelled in the nutrition labelling References FAO statistical pocketbook 2015: world food and agriculture. (2015). Rome: Food and Agriculture Organization of the United Nations. Food Composition Databases, Agricultural Research Service, United States Department of Agriculture, May 2016, ndb.nal.usda.gov/ndb/search/list. Simpson, B. K. (2012). Food biochemistry and food processing. Ames, IA: Wiley-Blackwell. Zhou, W., & Hui, Y. H. (2014). Bakery products science and technology. Oxford: Wiley-Blackwell. 43 44 11