Skrypt- uproszczona wersja- Carbohydrates-Hormones PDF

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Węglowodany, białka, tłuszcze 1.Food Science There are 3 main (główne) groups of constituents (składniki) in foods: carbohydrates, proteins, fats and derivatives (pochodne) of these. In addition there are inorganic and mineral components and a diverse (różna) group of organic substances present in small proportions that include such substances as vitamins, enzymes, emulsifiers, acids (kwasy), oxidants (utleniacze), antioxidants (przeciwutleniacze), and pigments. There is also (jest również) a very important constituent (bardzo wazny składnik), water. These components are in foods to give the foods their structure, texture, flavor (aromat), color, and nutritive value (wartość odżywcza). 1.1.Carbohydrates Carbohydrates (węglowodany) make up most of the organic matter on Earth because of their important (z powodu swojej istotnej roly) roles in all forms of life. First, carbohydrates serve (służą) as energy stores and fuels. Second, ribose and deoxyribose sugars form (tworzą) part of the structure of RNA and DNA. Third, polysaccharides are structural elements in the cell walls (ścian komórkowych) of bacteria and plants. Cellulose, the main constituent of plant cell walls, is one of the most common (powszechnych) organic compounds (związków organicznych) in the biosphere. Fourth (po czwarte), carbohydrates are linked (połączone) to many proteins and lipids, where they play key roles (kluczową role) in interactions between cells (interkacją pomiędzy komórkami) and interactions between cells and other elements (pierwiastek chemiczny) in the cellular environment (środowisko). Carbohydrates are simple organic compounds that are aldehydes or ketones with many hydroxyl groups, usually one on each carbon atom(po jednym na każdym atomie węgla) that is not part of the aldehyde (aldehydowej) or ketone (ketonowych) functional group (grup funkcjonalnych). The basic carbohydrate units are called (nazywamy) monosaccharides; examples are (przykłady to) mipawel.glucose, galactose, and fructose. Monosaccharides can be linked together into polysaccharides (or oligosaccharides). Many carbohydrates contain one or more modified monosaccharide units that have one or more groups replaced or removed. For example, deoxyribose, a component of DNA, is a modified version of ribose; chitin is composed of repeating units of N-acetylglucosamine, a nitrogencontaining form of glucose. Monosaccharides are the major source of fuel for metabolism, used as an energy source (glucose being the most important in nature) and in biosynthesis. Monosaccharides are often converted to polysaccharides. In many animals, including humans, this storage form is glycogen, especially in liver and muscle cells. In plants, starch is used for the same purpose. Foods rich in carbohydrates include breads, pastas, beans, potatoes, bran, rice, and cereals. Most such foods are rich in starch. Carbohydrates require less water to digest than proteins or fats and are the most common source of energy in living things. Proteins and fat are necessary building components for body tissue and cells, and are also a source of energy for most organisms.

Carbohydrates are not essential nutrients in humans: the body can obtain all its energy from protein and fats. However, the brain and neurons generally cannot burn fat and need glucose for energy; the body can make some glucose from a few of the amino acids in protein and also from the glycerol in triglycerides. Carbohydrate contains 3.75 and proteins 4 calories per gram, respectively, while fats contain 9 calories per gram. In the case of protein, only some amino acids are usable for fuel. Likewise, in humans, only some carbohydrates are usable for fuel, as in many monosaccharides and some disaccharides. Other carbohydrate types can be used, but only with the help of gut bacteria. Ruminants and termites can even process cellulose, which is indigestible to other organisms. Glossary: abundant- liczny bran- otręby compound- związek chemiczny constituent, component- składnik contain- zawierać convert- przekształcać digest- trawić gut- jelito likewise- podobnie major source- główne źródło obtain- uzyskać purpose- cel remove- usunąć replace- zastąpić require- wymagać ruminant- przeżuwacz store- zapas unit- jednostka Exercise 1 Complete the text with these terms: chain, disaccharide, glucose, hydrogen, hydroxyl, nucleic, photosynthesis, properties, starches. CARBOHYDRATES are organic compounds. Among the most important types of carbohydrates in foods are the sugars, dextrins, …….., celluloses, hemicellulloses, pectins and certain gums. Chemically carbohydrates contain only the elements of carbon, ………. and oxygen. Simple carbohydrates are called sugars. One of the simplest carbohydrates is the sixcarbon sugar, ………... Two glucose units may be linked together with the splitting out of a molecule of water. The result is the formation of a molecule of a ………….. Common disaccharides formed in similar way are sucrose (e.g., cane or beet sugar) made from glucose and fructose, maltose or malt sugar from two molecules of glucose and lactose or milk sugar from glucose and galactose. These disaccharides also differ from one another in solubility, sweetness, susceptibility to fermentation, and other ………….. A larger number of glucose units may be linked to form polysaccharides. One such polysaccharide is amylose, an important component of plant starches. A ……… of glucose units linked together in a slightly different way forms cellulose.

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The chemically reactive groups of sugars are the ………. groups (-OH) around the ring structure. Carbohydrates play an important role in biological systems and in foods. They are produced by …………… in green plants and are nature’s way of storing energy from sunlight. They may serve as structural components as in the case of cellulose, be stored as energy reserves as in the case of starch in plants and liver glycogen in animals, and function as essential components of ……….. acids as in the case of ribose, and as components of vitamins such as the ribose of riboflavin. Glucose in the blood is an important source of energy for animals.

Sources: 1. Potter N.N., Hotchkiss J.H.: Food Science, Aspen Publishers, 1998. 2. http://en.wikipedia.org/wiki/Carbohydrate

1.2. Proteins Proteins are made by linking individual amino acids together in long chains. Amino acids contain carbon, hydrogen, oxygen, and nitrogen. Some amino acids also contain other elements such as sulphur. Proteins are essential to all life. In animals they help form supporting and protective structures such as cartilage, skin, nails, hair, and muscle. They are major constituents of enzymes, antibodies, many hormones, and body fluids such as blood, milk, and egg white. Amino acids have the –NH 2, or amino group, and the –COOH or carboxyl group attached to the same carbon atom. These groups are chemically active and can combine with acids, bases, and other reagents. The amino and carboxyl groups are basic and acidic, respectively: the amino group of one amino acid readily combines with the carboxyl group of another. The result is the elimination of a molecule of water and formation of a peptide bond. When two amino acids react, a dipeptide is formed, with the peptide bond at the center. The remaining free amino and carboxyl groups at the ends can react with other amino acids forming polypeptides. Eight amino acids are called essential amino acids because they cannot be synthesized by humans in adequate amounts to sustain growth and health and must be supplied by the diet. The remaining amino acids are also necessary for health but can be synthesized by humans from other amino acids and nitrogenous compounds and are called nonessential. The essential amino acids are leucine, isoleucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. To this list of eight is added histidine important for growth during childhood. The nonessential amino acids are alanine, arginine, aspartic acid, cysteine, cystine, glutamic acid, glycine, hydroxyproline, proline, serine, and tyrosine. The products of protein degradation in order of decreasing size and complexity are protein, proteoses, peptone, polypeptides, peptides, amino acids, NH 3, and elemental nitrogen. The main role of proteins in the cell is as enzymes which catalyze chemical reactions.

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Glossary: amount- ilość antibodies- przeciwciała attached- przyłączony bond- wiązanie cartilage- chrząstka combine with- łączyć się z complexity- złożoność degradation- rozpad designate- określić element- pierwiastek essential- istotny principally- głównie reagent- odczynnik remaining- pozostały supplied by- dostarczony przez sustain- podtrzymać Exercise 2 Complete the text with these terms: containing, converted, digestion, essential, obtain, proteases, source, support, surroundings. Amino acids Most microorganisms and plants can biosynthesize all 20 standard amino acids, while animals (including humans) must ………. some of the amino acids from the diet. The amino acids that an organism cannot synthesize are called ……….amino acids. If amino acids are present in the environment, microorganisms can conserve energy by taking up the amino acids from their ………. . In animals, amino acids are obtained through the consumption of foods ………… protein. Ingested proteins are broken down through …….., which typically involves denaturation of the protein through exposure to acid and hydrolysis by enzymes called ……….. Some ingested amino acids are used for protein biosynthesis, while others are ……….. to glucose through gluconeogenesis, or go into the citric acid cycle. This use of protein as a fuel is particularly important under starvation conditions because it allows the body's own proteins to be used to …………. life, particularly those in muscle. Amino acids are also an important dietary ……….. of nitrogen. Sources: 1. Potter N.N., Hotchkiss J.H.: Food Science, Aspen Publishers, 1998. 2. http://en.wikipedia.org/wiki/Protein

1.3. Fats and oils Fats are smooth, greasy substances that are insoluble in water.

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Fat is mainly a fuel source for animals or plants. It contains about 2 1/4 times the calories found in an equal dry weight of protein or carbohydrate. Fat always has other substances associated with it in natural foods, such as the fat-soluble vitamins A, D, E and K, the sterols, cholesterol in animal fats and ergosterol in vegetable fats, and certain natural lipid emulsifiers called phospholipids, because of the presence of phosphoric acid in their molecules. A typical fat molecule consists of glycerol combined with three fatty acids. Glycerol has three reactive hydroxyl groups, and fatty acids have one reactive carboxyl group. Therefore, three fatty acid molecules can combine with each glycerol molecule, eliminating three molecules of water. Such fats are called triglycerides. There are about 20 different common fatty acids that are connected to glycerol in natural fats. These fatty acids differ in length and in the number of hydrogen atoms they contain. Fat molecules do not need all three hydroxyl groups of glycerol to react with fatty acids. When two groups react, the molecule is known as a diglyceride, when glycerol combines with only one fatty acid molecule, the fat is called a monoglyceride. Diglycerides and monoglycerides have special emulsifying properties. Natural fats are not made up of fat molecule but are mixtures of many types. Fats or lipids are broken down in the body by enzymes called lipases produced in pancreas. Examples of edible animal fats are lard (pig fat), fish oil, and butter. They are obtained from fats in the milk, meat, and under the skin of the animal. Examples of edible plant fats are peanut oil, soybean oil, sunflower oil, sesame oil, coconut oil, olive and vegetable oils. Margarine and vegetable shortening are used mainly for baking. These examples of fats can be categorized into saturated and unsaturated fats. Glossary: associated with- związany z be made up of- być złożonym z chyme /kaim/- miazga pokarmowa, chymus common- powszechny dry weight- sucha masa edible- jadalny endocrine- dokrewny equal- równy fuel- materiał energetyczny greasy- tłusty insoluble- nierozpuszczalny lard- smalec permeability- przepuszczalność properties- właściwości saturated- nasycony shortening- tłuszcz piekarniczy therefore- dlatego Exercise 3 Complete the definitions with these terms: cholesterol, hydroxyl group, insoluble, molecule, pancreas, source. ……………. substance is a substance which is not able to dissolve in a liquid solvent to form a homogeneous solution.

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A ……….. is the start, beginning, or origin of something. …………….. is a waxy steroid metabolite found in the cell membranes and transported in the blood plasma of all animals. It is an essential structural component of mammalian cell membranes, where it is required to establish proper membrane permeability and fluidity. In addition, ……….. is an important component for the production of bile acids, steroid hormones, and fat-soluble vitamins including Vitamin A, Vitamin D, Vitamin E, and Vitamin K. It is the principal sterol synthesized by animals, but small quantities are synthesized in other eukaryotes, such as plants and fungi. Although it is an important and necessary molecule for animals, a high level of serum ……. is an indicator for diseases such as heart disease. A …………… is defined as an electrically neutral group of at least two atoms held by very strong (covalent) chemical bonds. It may consist of atoms of a single chemical element, as with oxygen (O2), or of different elements, as with water (H 2O). As a component of matter it is common in organic substances. The term ………………….. is used to describe the functional group –OH when it is a substituent in an organic compound. Organic molecules containing it are known as alcohols. It occurs in molecules of carbohydrates. The …………….. is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as an exocrine gland, secreting pancreatic juice containing digestive enzymes that pass to the small intestine. These enzymes help to further break down the carbohydrates, proteins, and fats in the chyme. Sources: 1. Potter N.N., Hotchkiss J.H.: Food Science, Aspen Publishers, 1998. 2. http://en.wikipedia.org/wiki/Fat 3. http://en.wikipedia.org/wiki

1.4. Dietary Fibre Dietary fiber is a heterogeneous mixture of plant food components that are indigestible in the small intestine. The definition of dietary fiber in the last few decades is: ”Dietary fiber consists of the remnants of edible plant cell, polysaccharides, lignin, and associated substances resistant to digestion by the alimentary enzymes of humans”. The term is generally used to describe the supporting structures of plant cell walls and the substances associated with them. The typical components of dietary fiber include cellulose, hemicellulose, lignins, pectins, and gums and mucilages. All of these except lignins are polysaccharides. The heterogeneity of dietary fiber is the primary reason for the diversity of its physiological effect. Dietary fiber is available in the human diet through a wide variety of food sources, such as raw and processed cereals, vegetables, legumes, and fruits. The composition of dietary fiber varies with the type of plant tissue. The proportions of different dietary fiber constituents found in plant foods depend on the maturity of the plants. In typical plant cell walls, the percentage of cellulose, lignin, and ash is higher and the percentage of noncellulose

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polysaccharides, waxes, and protein is lower in mature than in immature plants. The portion of the plant consumed and its relative maturity, as well as storage and ripening, may influence the dietary fiber composition of plant foods, and food-processing techniques may also change fiber composition. Vegetables and cereals are good sources of cellulose. Lignin is highest in fruits with edible seeds such as strawberries or in mature vegetables such as carrots or other root vegetables. Whole grain cereals and bran are rich in hemicellulose. Pectin is found in fruits such as apples and oranges. Oats and dried beans contain a good source of soluble dietary fiber. Total dietary fiber includes both water-insoluble and water-soluble dietary fiber. Insoluble fiber consists mainly of cell wall components such as cellulose, lignin, and hemicellulose present mainly in wheat, most grain products, and vegetables. Insoluble fiber shortens bowel transit time, increases fecal bulk. Soluble fiber consists of noncellulosic polysaccharides such as pectin, gums, and mucilages found in fruits, oats, barley, and legumes. Soluble fiber delays gastric emptying, slows glucose absorption, enhances immune function and lowers serum cholesterol levels. It is to a large degree fermented in the colon into short-chain fatty acids, which may inhibit hepatic cholesterol synthesis. About 75% of the dietary fiber in foods is insoluble. Glossary: absorption- wchłanianie alimentary enzymes- enzymy trawienne colon- okrężnica delay- opóźniać diversity- różnorodność enhance- poprawiać fecal bulk- masa kałowa feces- kał, stolec gum- żywica heterogenous mixture- miszanina niejednorodna indigestible- niestrawny inhibit- hamować legumes- rośliny strączkowe mucilage- klej rośllinny processed- przetworzony remnants- resztki ripening- dojrzewanie serum- surowica small intestine- jelito cienkie term- pojęcie wide variety- duża różnorodność Exercise 4 Match the words from A with the words from B: A alimentary cell consist depend dietary

fatty food heterogenous plant resistant small

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wide B fiber mixture intestine of enzymes wall variety tissue on processing to acids

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Source: Sungsoo Cho Susan, Dreher M.L.: Handbook of Dietary Fiber, Marcel Dekker, Inc., 2001

1.5. Dietary minerals Dietary minerals are a group of inorganic elements that are essential to humans and animals for normal body function. In nutrition, minerals are those elements for which the body's requirement is at least 100 mg per day, and trace minerals are those elements that are needed in smaller amounts. Plants take the minerals from the soil, and humans and animals consume the plants. There are seven major minerals. Calcium occurs mainly in the teeth and bones, but a small amount is found in blood plasma and other body fluids, where it influences nerve transmission, blood clotting, and muscle contraction. Dairy products and green leafy vegetables are dietary sources of calcium, and an adequate intake of vitamin D is required for calcium absorption. Phosphorus, also found in dairy products, helps in bone and tooth formation. It is present in every cell in compounds such as nucleic acids and adenosine triphosphate. Magnesium, also present in every cell, is necessary for carbohydrate and protein metabolism, cell reproduction, and smooth muscle action. Dietary sources include nuts, soy beans, and cocoa. Sodium is in the skeleton and extracellular fluids, and is necessary for fluid and acid-base balance, cell permeability, and muscle function. It occurs in table salt (sodium chloride, the main source) and such foods as milk and spinach. Potassium, which is found in intra- and extracellular fluid, plays an important role in fluid and electrolyte balance and in heart muscle activity, and is also required for carbohydrate metabolism and protein synthesis. Its sources include legumes, whole grains, and bananas. Chlorine is found in extracellular fluid, where it helps maintain normal fluid-electrolyte and acid-base balance, and in the stomach, where it helps provide the acidic environment necessary for digestion. Table salt is its main dietary source. Sulfur, which is important to the structure of proteins, is also necessary for energy metabolism, enzyme function, and detoxification. Sulfur is obtained from protein foods, such as meat, eggs, and legumes. Some trace minerals are considered “essential” in human nutrition. The essential trace minerals include iron, which is a constituent of hemoglobin; iodine, which is necessary for thyroxine synthesis;...