Bread carbohydrates

Morgan, K R., Furneaux, R. H., and Stanley, R. A. (1992). Observation by solid-state -3C CP MAS NMR spectroscopy of the transformations of wheat starch associated with the making and staling of bread. Carbohydr. Res. 235 15-22. 

Lactic Acid B cteri. The lactic acid bacteria are ubiquitous in nature from plant surfaces to gastrointestinal tracts of many animals. These gram-positive facultative anaerobes convert carbohydrates (qv) to lactic acid and are used extensively in the food industry, for example, for the production of yogurt, cheese, sour dough bread, etc. The sour aromatic flavor imparted upon fermentation appears to be a desirable food trait. In addition, certain species produce a variety of antibiotics. 

When compared to whole meal rye flour (280 kcal/1160 kJ) and to wheat flour (320 kcal/1320 kJ), phloem powder (140 kcal/580 kJ) contains approximately 50% less energy. As is typical for all flours, phloem powder also contains a low amount of fat (total amount 2.3 g/100 g). The protein content of phloem is only 2.5 g (per 100 g), whereas the respective amount in whole meal rye flour is 8.8 g and in wheat flour 12.1 g. The content of carbohydrates in phloem ( 30 g/100 g) is about 50% less than in rye (55 g) and wheat flours (59 g). The relatively low energy, protein and carbohydrate content of phloem when compared with commonly used flours, is related to its high content of different fiber. Detailed nutritional data for phloem and phloem breads used in our trial are presented in Table 14.1. 

They do differ in one respect from their filamentous siblings in that they are able to metabolise certain carbohydrates (sugars) by a process known as fermentation. During this, of course, they produce alcohol and gas (carbon dioxide) and for that reason they are used in brewing, bread making and other useful processes. 

Producers of cakes, biscuits and pastries are in a less easy position. While bread is a staple food containing complex carbohydrates and is essentially sugar free and low in fat, cakes, biscuits and pastries contain quantities of sugar and fat. They are also regarded as non-essential foods. 

Commonly the products are sold to slimmers under a trade name as carbohydrate or starch reduced. Of course the product contains less carbohydrate, i.e. starch than ordinary bread because the percentage of protein has been increased. 

Reducing diets seem to come and go. At the time of writing the popularity of the Atkins diet seems to be decreasing. The Atkins diet is a low carbohydrate diet that is not conducive to the sales of baked products however, the Atkins diet seems to be being superseded by diets based on the principle of a low glycemic index. This is unlikely to increase the sale of baked goods but is less antipathetic to them. A new diet based on bread has appeared and so the wheel may go full circle. 

V American dietitians and members of the medical community have ridiculed low-carbohydrate diets as quackery for the past thirty years, while extolling a diet that cuts down on fat, limits meat consumption, and relies on carbohydrates as its staple. Many Americans are famil-(V iar with the food pyramid promoted by the U.S. government, with its foundation of carbohydrates such as breads, rice, and pasta, and its apex allotted to fats, oils, and sweets. Adhering to the government s... 

Defined sources of food were therefore required. By 1905-1906 diets consisting solely of purified protein, carbohydrate and fat were shown to be inadequate to sustain life. Lunin (1881) and Pekelharing (1905) established that white mice fed a bread baked with casein, albumin, rice-flour, lard, and a mixture of all the salts which ought to be found in their food, with water to drink, starve to death. For the first few days all is well, the diet is eaten, and the animals look healthy. But they all get thinner, their appetite diminishes, and in four weeks all are dead. If however, instead of water they are given milk to drink, they are kept in... 

Carbohydrates are found in foods such as bread, pasta, potatoes, and fruits. They are the primary source of energy for the body. In a process called cellular respiration, carbohydrates combine with inhaled oxygen and are oxidized to produce carhon dioxide and water, plus energy. As shown in Figure 2.18, carhon dioxide and water vapour from cellular respiration are expelled in your hreath. 

Suppose we start with a starch-rich meal, say one containing a lot of pasta or bread. The digestion of starches begins in the mouth. Saliva contains an enzyme, salivary amylase (aka ptyalin), which catalyzes the conversion of starch to simple sugars such as glucose. This process is completed in the small intestine under the influence of other enzymes in the amylase class. This completes the first phase of carbohydrate catabolism the conversion of complex, polymeric carbohydrates (e.g., starches) to their simple monomeric units, the sugars. 

Figure 13.1 (a) Blood glucose responses to 50 g available carbohydrate portions of potatoes, bread, and glucose (reference) and to a serving of bread and potato (Monro et al., 2008). (b) Food intakes that gave the responses shown in (a). 

Although most naturally occurring lipids contain fatty acids with an even number of carbon atoms, fatty acids with an odd number of carbons are common in the lipids of many plants and some marine organisms. Cattle and other ruminant animals form large amounts of the three-carbon propionate (CH3—CH2—COO ) during fermentation of carbohydrates in the rumen. The propionate is absorbed into the blood and oxidized by the liver and other tissues. And small quantities of propionate are added as a mold inhibitor to some breads and cereals, thus entering the human diet. 

In 2002, workers at the. Swedish National Food Administration discovered that heated, carbohydrate-rich foods, such as french fries, potato chips, and bread, contain alarming levels (0.1 to 4 p,g/g) of acrylamide, a known carcinogen.27... 

Breads, cereals, grains, pastas, fruits, and vegetables are important sources of food primarily because they contain a good balance of all nutrients—carbohydrates, fats, proteins, nucleic acids, vitamins, and minerals. The predominant component of these foods is carbohydrates, however. 

Hydroxypyran-4-ones are potent flavouring materials of which maltol (427), present in roasted malt, is particularly well known. Amongst other features, it imparts a newly baked odour to bread. Kojic acid (712) is produced in an aerobic process by a range of microorganisms, notably Aspergillus oryzae, from a variety of carbohydrate sources and is used as a source of maltol. 

The numbers quoted in Table 8.4 are not very precise, and different reference sources often give different values. Part of the problem is that the source and variety of the food can cause large differences—an "apple," for instance, may be any one of over a hundred varieties and may come from practically any country on Earth. Perhaps even more important is that many foods—carbohydrates such as bread, in particular—contain a large but variable amount of water, which increases the mass of the food but adds no caloric value. 

Digestion starts in the mouth, where saliva breaks down starch (a complex carbohydrate) into sugar (a simple one). This is why chewing on a piece of bread for a long time makes it start to taste... 

Many chemical reactions occur in the kitchen. For example, some types of breads, called yeast breads, rely on the chemical reactions of tiny microbes to make them look and taste the way they do. The microbes, in this case, are yeast spores mixed into the bread dough. Yeast spores are tiny living things that can only be seen under a microscope. When yeast is mixed into bread dough, they feed on the carbohydrates in the flour and produce carbon dioxide gas and alcohol. This process is called fermentation. 

Increase significantly your intake of carbohydrates. This includes whole-grain breads, cereals, pasta, rice, fruits, vegetables, legumes and grains such as barley. 

Browning of breads, as induced by baking, is a complex process consisting mainly of the Maillard reaction between flour starch or other carbohydrates and flour protein or other protein-rich additives, and the caramelization of sugar and other carbohydrates. 

Bread is an excellent staple supplying key nutrients carbohydrates, proteins, minerals, and vitamins. Its nutritive value affects a great majority of the human population. The marked increase in nutritive value of microwave or steamed breads, observed in the present study, indicates that those processes deserve attention or that conventional baking warrants some modification. 

Fruits, vegetables, and whole-grain breads and cereals contain carbohydrates. This is also true of cookies, cakes, and most other sweets, since both flour and sugar come from plants—flour from wheat, and sugar from sugar cane. Potatoes, beans, popcorn, and rice are other examples of foods with carbs. 

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