HISTORY OF BREADBread is one of the oldest prepared foods. Evidence from 30,000 years ago in Europe revealed starch residue on rocks used for pounding plants. It is possible that during this time, starch extract from the roots of plants, such as cattails and ferns, was spread on a flat rock, placed over a fire and cooked into a primitive form of flat bread. Around 10,000 BC, with the dawn of the Neolithic age and the spread of agriculture, grains became the mainstay of making bread. Yeast spores are ubiquitous, including the surface of cereal grains, so any dough left to rest will become naturally leavened.

There were multiple sources of leavening available for early bread. Airborne yeasts could be harnessed by leaving uncooked dough exposed to air for some time before cooking. Pliny the Elder reported that the Gauls and Iberians used the foam skimmed from beer to produce "a lighter kind of bread than other peoples."

Parts of the ancient world that drank wine instead of beer used a paste composed of grape juice and flour that was allowed to begin fermenting, or wheat bran steeped in wine, as a source for yeast. The most common source of leavening was to retain a piece of dough from the previous day to use as a form of sourdough starter. A major advance happened in 1961 with the development of the Chorley wood bread process, which used the intense mechanical working of dough to dramatically reduce the fermentation period and the time taken to produce a loaf. The process, whose high-energy mixing allows for the use of lower protein grain, is now widely used around the world in large factories. As a result, bread can be produced very quickly and at low costs to the manufacturer and the consumer. Recently, domestic bread machines that automate the process of making bread have become popular.

THE PROCESS OF BREAD MAKINGBread, food prepared by baking flour obtained by grinding the cereals, wheat, rye, millet, barley, oats or maize, or other vegetable products, such as beans, peas, or tapioca. Bread-making appears to have been practised from the very earliest times, as cakes of barley have been discovered in Stone Age dwellings. Baking was understood by the ancient Egyptians and Chaldeans, and it is said of Abraham that he commanded Sarah to make ready three measures of fine meal, knead it and make cakes upon the hearth. The Romans established public bakehouses, from which free distributions of bread took place. Because of the widespread cultivation of cereals in North America and throughout Europe, various types of bread have become used as a staple food in these parts of the world. Wheat flour is most often used, but in various regions maize, rye, barley and millet are also important.

NUTRITIONAL VALUE OF BREADBread and flour play an important part in the diet of people living in northern Europe and North America. On the average four slices of bread will supply 250 calories, that is between one tenth and one quarter of energy requirements per day, depending on the individual's activity. More importantly, this quantity of bread will supply one quarter of the daily requirements of protein, iron and nicotinic acid; over one fifth of calcium and almost one third of the daily requirement of thiamine (vitamin B,). It is important, therefore, for those who are anxious to reduce their calorie intake that, if they do so by cutting down on the amount of bread in the diet, they supplement the diet to provide the other nutrients. As bread is a staple food in many parts of the world, nutritionists were concerned that the nutrient content of flour should not be lost by commercial methods for improving product acceptability, such as refining the flour, and adding chemicals to increase bulk, delay staling, and to give a finer texture. During World War II, the Government passed regulations that certain nutrients should be added to white flour, so that its nutrient content would not be nutritionally inferior to unrefined brown flour. These regulations specify that the final concentration of calcium carbonate must be between 250-300 mg per 100 g flour, and that the levels of iron, thiamine and nicotinic acid do not fall below 1.65 mg, 0.24 mg, and 1.6 mg respectively per 100 g of flour. From the following table, it is clear that the nutritional content of white bread is now almost equivalent to unrefined brown bread.

Recently there has been an increasing interest in the nutrient content of bread, with considerable publicity in the press, television advertisements, and in the rapidly expanding cookery/nutrition/diet journals. This has resulted in a wider variety of products being sold, including soda, wholemeal, wheatmeal, granary, milk, protein-enriched, and starch-reduced breads. Perhaps the most pertinent advice for consumers on the nutritional content of these different types of bread, is to read the information given on the packaging and consider the weight of that product that will be eaten. Only in this way is a comparison of nutritional values meaningful. THE PROCESS OF BREAD MAKINGBread is most commonly made from a mixture of flour, salt, water, and the rising agent yeast. Unleavened bread contains no fermenting or rising agent, and is less common than leavened bread. Yeast is a microscopic fungus. The cells reproduce in warm, moist conditions by splitting sugar molecules forming carbon dioxide and alcohol, which are given off as gases and act as the raising agents in the process of bread making.

The production of carbon dioxide from yeast and flour is a complicated process. Flour contains two per cent sucrose and the enzyme diastase, which changes some of the starch of the flour to the sugar maltose; the yeast also contains three enzymes- two of which, maltase and sucrase, convert these large complex sugar molecules to the simple sugars, glucose and fructose. The third enzyme, zymase, splits both glucose and fructose into carbon dioxide and alcohol. Because of these complex reactions, the process requires certain optimum conditions: a temperature of between 25 ° and 28 °C in the rising periods, a supply of water, sugar, and time, which varies conversely with the proportion of yeast to flour. The intense heat of baking (about 200°C) is sufficient to kill the yeast cells, thus preventing further reactions. The gluten in the flour, which has been stretched during the rising period, is coagulated in the extended position, giving a light, spongy texture to the dough.

In mixing dough on a large scale a 'sponge' is first prepared. This consists of part of the flour, most of the water and all the yeast required for the whole batch, with a small quantity of salt. The sponge is allowed to ferment for from six to ten hours, and then mixed with the remainder of the flour, water and salt. The dough is kneaded in a bowl or trough in which blades revolve, thoroughly mixing the ingredients. In a small bakery the oven may be 3 m long, 24 m wide and 0.8 m high. In large steam bakeries the loaves take about 45 minutes to travel through a tunnel oven which may be 30 m long or more. The oven is heated by a furnace or by super-heated steam. Bread supplies a significant portion of the nutrients required for growth, maintenance of health and well-being. It is an excellent source of proteins, vitamins, minerals, fibre and complex carbohydrates. It is also low in fat and cholesterol. Bread is quite bulky so it takes longer to digest and is therefore more satisfying and less fattening than the fats, sugars and alcohols commonly consumed in excess. All breads are nutritious, and the differences between them in nutritional value are not significant if we eat a balanced diet.

CHEMICAL COMPOSITION OF WHEATThe composition of the dry matter of wheat varies widely depending on soil, climate and genetic variations between wheat types. Wheat in New Zealand has a protein content that ranges on average from 8% to 13%. It has a high carbohydrate content of about 83% of the weight of a kernel.Other components of the wheat grain include bran and germ. Bran, the outer coating or "shell", is rich in B vitamins and minerals.The wheat germ or embryo is a rich source of B vitamins, oil, vitamin E and fat. It needs to be discarded during milling because the fat is liable to become rancid during storage. It is still very valuable and is used in many products.Minerals contained in wheat include calcium, phosphorous, potassium, iron, magnesium and sodium.Vitamins such as thiamine (B1), riboflavin (B2), pantothenic acid, inosotol, P-aminobenzoic acid, folic acid and vitamin B6 are also distributed throughout the wheat grain.

All the nutrients contained in wheat make bread an essential part of the diet. Bread is one of the cheapest, high quality nutritious foods in New Zealand and not only provides many essential nutrients but is also low in fat, cholesterol and sugar. DID YOU KNOW THAT ALL BREAD IS NUTRITIOUS?White bread has approximately the same carbohydrate and protein content as wholemeal bread, contains soluble and insoluble dietary fibre, and a good percentage of the whole wheat nutrients. It is made from unbleached flour made from the inner 78% of the wheat grain. If you prefer white bread to wholegrain breads, you can get your extra fibre from other wholegrain foods such as breakfast cereals, wholemeal crackers and biscuits.

In New Zealand wholemeal bread is made from at least 90% wholemeal flour. White flour may be added to wholemeal flour to make wheat meal products.It is often added to improve the baking quality of breads made with wholemeal flour because of its gluten protein content.Wheat meal breads are not subject to food regulations and so the quantity of wholemeal flour used may vary. Nutritional comparisons are therefore difficult to make.How does bread meet our nutritional needs?Comparisons of bread with other commonly eaten foods important in the New Zealand diet, show that bread provides a greater range of nutrients than any of the other food products listed.