Food Science and Nutrition: Structures, Functions, and Composition of Food, Resúmenes de Nutrición

¡Descarga Food Science and Nutrition: Structures, Functions, and Composition of Food y más Resúmenes en PDF de Nutrición solo en Docsity! INGLÉS 3825 GRADO EN NUTRICIÓN Y DIETÉTICA UNIT 2: FOOD SCIENCE Docente: Fuensanta Mª Piqueras Casado Universidad de Murcia 1. THEORY UNIT 1: STRUCTURES AND FUNCTIONS OF THE HUMAN BODY UNIT 2: FOOD SCIENCE AND FOOD TECHNOLOGY UNIT 3: FOOD HYGIENE AND FOOD SAFETY UNIT 4: NUTRITION, DIETETICS AND HEALTH UNIT 5: COMMUNITY NUTRITION 2. FOOD SCIENCE: AN INTERDISCIPLINARY SCIENCE Product development: the invention of new food products Sensory analysis: the study of how food Is perceived by the consumer's senses Food chemistry: the molecular composition of food and the involvement of these molecules in chemical reactions Food packaging: the study of how packaging is used to preserve food after it has been processed and contain it through distribution Food technology: the technological aspects of food Food physics: the physical aspects of foods (such as viscosity, creaminess, and texture) 3. BASIC COMPOSITION OF FOOD  Our body requires: carbohydrates, proteins, fats, enzymes, vitamins and minerals for a healthy growth.  However, our body cannot produce all these nutrients.  Hence, food is the only source to obtain these nutrients in an adequate quantity. If we do not get these nutrients in sufficient amount, then we may suffer from a number of health problems.  These nutrients also differ in how quickly they supply energy. Carbohydrates are the quickest, and fats are the slowest. Carbohydrates, proteins, and fats are digested in the intestine, where they are broken down into their basic units: carbohydrates into sugars, proteins into amino acids, and fats into fatty acids and glycerol. The body uses these basic units to build substances it needs for growth, maintenance, and activity (including other carbohydrates, proteins, and fats). 3. BASIC COMPOSITION OF FOOD: WATER  Water:  A combination of hydrogen and oxygen which is the basis for the fluids of the body (it makes up more than two-thirds of the weight of the human body) 1. Functions: - It serves as a lubricant and is the basis of saliva and the fluids surrounding the joints - It regulates the body temperature through perspiration - It also helps prevent and alleviate constipation by moving food through the intestinal tract 2. Food Sources: Water can be obtained: - Through foods we eat - As the byproduct of metabolism - Drinking water is our main, and best, source of water - Through liquid foods and beverages, such as soup, milk, and juices.  Alcoholic beverages and beverages containing caffeine (such as coffee, tea, and colas) are not the best choices because they have a diuretic (water-excreting) effect. 3. Side Effects: - If adequate water is not consumed on a daily basis the body fluids will be out of balance, causing dehydration 3. BASIC COMPOSITION OF FOOD: DIETARY FIBER Dietary fiber (fibre) has two main components: soluble (prebiotic, viscous) fiber and insoluble. Food sources of dietary fiber are often divided according to whether they provide predominantly) soluble or insoluble fiber. Plant foods contain both types of fiber in different degrees according to the plant's characteristics. 1. Sources of fiber - Dietary fiber is found in plants. Fiber-rich plants can be eaten directly. Or, alternatively, they can be used to make supplements and fiber-rich processed foods. - Soluble fiber is found in varying quantities in all plant foods, including: legumes (peas, soybeans, and other beans), oats, rye, chia, and barley some fruits and fruit juices (including plums, berries, bananas, and the insides of apples and pears) certain vegetables such as broccoli, carrots, root vegetables such as potatoes, sweet potatoes, and onions (skins of these vegetables are sources of insoluble fiber) psyllium seed husk (a mucilage soluble fiber). - Sources of insoluble fiber include: whole grain foods wheat and corn bran nuts and seeds potato skins flax seed lignans vegetables such as green beans, cauliflower, zucchini (courgette), celery, and nopal some fruits including avocado, and bananas the skins of some fruits, including tomatoes 3. BASIC COMPOSITION OF FOOD: DIETARY FIBER 2. Mechanism The main action of dietary fiber is to change the nature of the contents of the gastrointestinal tract, and to change how other nutrients and chemicals are absorbed. Benefits of fiber intake Research has shown that fiber may benefit health in several different ways. Dietary fiber functions & benefits • Guidelines on fiber intake Authorities generally recommend that about 30 grams of fiber be consumed daily. The average amount of fiber consumed daily is usually less because people tend to eat products made with highly refined wheat flour and do not eat many fruits and vegetables. Meat and dairy foods do not contain fiber. An average serving of fruit, a vegetable, or cereal contains 2 to 4 grams of fiber and should be the part of the diet. 3. BASIC COMPOSITION OF FOOD: DIETARY FIBER Type of fibre Functions Benefits Soluble /insoluble Adds bulk to your diet making you feel full faster May reduce appetite Soluble Attracts water and turns to gel during digestion, trapping carbohydrates and lowing absorption of glucose Lowers variance in blood sugar levels Soluble Lowers total and LDL cholesterol Reduces the risk of heart disease Soluble Regulates blood sugar May reduce onset risk or symptoms of metabolic syndrome and diabetes Soluble Balances intestinal pH and stimulates intestinal fermentation production of short-chain fatty acids May reduce risk of colorectal cancer Insoluble Speeds the passage of foods through the digestive system Facilitates regularity Insoluble Adds bulk to the stool Alleviates constipation 3. BASIC COMPOSITION OF FOOD: FATS 4. Food sources: - Fish and shellfish, soya oil, canola (rapeseed) oil, pumpkin seeds, sunflower seeds, leafy vegetables, and walnuts contain fats. A low fat diet can result in a number of illnesses, including osteoporosis. - Fats can also be found in plants Presence in food - Milk and meat from cows and other ruminants contains naturally occurring trans fats in small quantities. - Animal-based fats were once the only trans fats consumed, but by far the largest amount of trans fat consumed today is created by the processed food industry. - Trans fats are used frying in restaurants, as they can be used for longer than most conventional oils before becoming rancid. - Fast food chains routinely use different trans fats to enrich the taste of their food 3. BASIC COMPOSITION OF FOOD: FATS • 5. Health risks: - Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems. - Obesity increases the likelihood of various diseases, particularly heart disease, type 2 diabetes, breathing difficulties during sleep, certain types of cancer, and osteoarthritis. - Obesity is most commonly caused by a combination of excessive dietary calories, lack of physical activity, and genetic susceptibility, although a few cases are caused primarily by genes, endocrine disorders, medications or psychiatric illness. Obesity is a leading preventable cause of death worldwide, with increasing prevalence in adults and children, and authorities view it as one of the most serious public health problems of the 21st century. 3. BASIC COMPOSITION OF FOOD: PROTEINS 1. Introduction and functions - Proteins are important dietary constituents and perform a wide range of functions like:  Providing structure to the body  Transporting oxygen and other substances within an organism  Regulating the body chemistry: forming blood cells and making antibodies to protect us from illness and infections Proteins are essential not only as constituents of food but they also have a significant role to play in the processing and preparation of food. - Next to water, protein is the most plentiful substance in our bodies. Muscles are made of protein and other important parts of the body like hair, skin, eyes, and body organs are all made from protein. Many substances that control body functions, such as enzymes and hormones, also are made from protein. Other important functions of protein include. 3. BASIC COMPOSITION OF FOOD: VITAMINS 1. Introduction and functions - A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. - Vitamins have diverse biochemical functions:  They can work as regulators of mineral metabolism (e.g. vitamin D), or regulators of cell and tissue growth and differentiation (e.g. some forms of vitamin A).  Others function as antioxidants (e.g. vitamin E and sometimes vitamin C). 2. Classification: In humans there are 13 vitamins  Water-soluble: 9 (8B vitamins and vitamin C) - Dissolve easily in water, and in general, are readily excreted from the body, to the degree that urinary output is a strong predictor of vitamin consumption  Fat soluble: 4 (A, D, E and K) 3. BASIC COMPOSITION OF FOOD: VITAMINS 3. Role of vitamins - Vitamins are essential for the normal growth and development of a multicellular organism. - For the most part, vitamins are obtained with food, but a few are obtained by other means. For example, microorganisms in the intestine—commonly known as "gut flora"—produce vitamin K and biotin, while one form of vitamin D is synthesized in the skin with the help of the natural ultraviolet wavelength of sunlight. 4. Deficiencies: - Because human bodies do not store most vitamins, humans must consume them regularly to avoid deficiency.  A primary deficiency occurs when an organism does not get enough of the vitamin in its food.  A secondary deficiency may be due to an underlying disorder that prevents or limits the absorption or use of the vitamin, due to a “lifestyle factor”, such as smoking, excessive alcohol consumption, or the use of medications that interfere with the absorption or use of the vitamin. People who eat a varied diet are unlikely to develop a severe primary vitamin deficiency. 3. BASIC COMPOSITION OF FOOD: VITAMINS 5. Side effects and overdose - In large doses, some vitamins have documented side effects that tend to be more severe with a larger dosage. The likelihood of consuming too much of any vitamin from food is remote, but overdosing from vitamin supplementation does occur. At high enough dosages some vitamins cause side effects such as nausea, diarrhea, and vomiting. 3. BASIC COMPOSITION OF FOOD: VITAMINS VITAMIN FUNCTIONS SIGNIFICANT FOOD SOURCE DEFICIENCY DISEASES Folate Supports DNA synthesis and new cell formation Tomato juice, green beans, broccoli, spinach, asparagus, letins, pinto and garbanzo beans Deficiency during pregnanct is associated with birth defects, such as neural tube defects B12 Used in new cell synthesis, helps break down fatty acids and amino acids, supports nerve cell maintenance Meats, poultry, fish, shellfish, milk, eggs Megalobrastic anemia C (ascorbic acid) Collagen synthesis, amino acid metabolism, helps iron absorption, immunity, antioxidant Spinach, broccoli, kiwi, mango, orange, grape fruit juice, strawberries Scurvy 3. BASIC COMPOSITION OF FOOD: VITAMINS VITAMIN FUNCTIONS SIGNIFICANT FOOD SOURCE DEFICIENCY DISEASES D Promotes bone mineralization Self-synthesis via sunlight, fortified milk, egg yolk, liver, fatty fish Rickets in children and osteomalacia in adult E Antioxidant, regulation of oxidation reactions, supports cell membrane stabilization Polyunsatured plant oils (soyabean, corn), wheat germ, sunflower seeds, tofu, avocado, sweet potatoes, shrimp, cod Deficiency is rare; mild heamolytic anema in newborn infants K Synthesis of blood-clotting proteins, regulates blood calcium Brussels sprouts, leafy green vegetables, spinach, broccoli, cabbage, lver Bleeding diathesis Increases clotting time of blood 3. BASIC COMPOSITION OF FOOD: MINERALS 1. Introduction - Dietary minerals: are the chemical elements required by living organisms, other than the four elements carbon, hydrogen, nitrogen, and oxygen present in common organic molecules. Appropriate intake levels of certain chemical elements are thus required to maintain optimal health. - Essential dietary minerals: Our body needs larger amounts of some minerals, such as calcium, to grow and stay healthy. Other minerals like chromium, copper, iodine, iron, selenium, and zinc are called trace minerals because we only need very small amounts of them each day. 3. BASIC COMPOSITION OF FOOD: MINERALS MINERAL FUNCTIONS SIGNIFICANT FOOD SOURCE DEFICIENCY DISEASES Selenium Antioxidant, works with vitamin E to protect body from oxidation Seafood, meats and grains Impaired thyroid function, impaired cardiac function, enlarged heart, necrosis of liver Iodine Component of thyroid hormones that help regulate growth, development and metabolic rate Salt, seafood, bread, milk, cheese Goitre (enlargement of thyroid grand) Copper Necessary for the absorption and utilization of iron, supports formation of haemoglobin and several enzymes Meats, water Rare in adults, Infants may develop a type of anemia marked by abnormal development of bones, nerve tissue and lungs 3. FOOD TECHNOLOGY: AN INTERDISCIPLINARY SCIENCE The food we consume on a daily basis is the result of extensive food research, a systematic investigation into a variety of foods’ properties and compositions. After the initial stages of research and development comes the mass production of food products using principles of food technology. 3. FOOD TECHNOLOGY Effects of Food Processing on Food Nutrition: Freezing, Drying, Cooking, and Reheating - Nearly every food preparation process reduces the amount of nutrients in food. In particular, processes that expose foods to high levels of heat, light, and/or oxygen cause the greatest nutrient loss. - Nutrients can also be "washed out" of foods by fluids that are introduced during a cooking process. For example, boiling a potato can cause much of the potato's B and C vitamins to migrate to the boiling water. You'll still benefit from those nutrients if you consume the liquid (i.e. if the potato and water are being turned into potato soup), but not if you throw away the liquid. - Similar losses also occur when you broil, roast, or fry in oil, and then drain off the drippings. 3. FOOD TECHNOLOGY: GRILLING MEATS Risks of meat grilling: - Outdoor grilling is a popular cooking method, primarily because of the wonderful taste it imparts on meats. It can also be a healthy alternative to other cooking methods, because some of the meat's saturated fat content is reduced by the grilling process.  However, two separate types of carcinogenic compounds are produced by high-temperature grilling: - Heterocyclic Amines (HCAs) form when a meat is directly exposed to a flame or very high-temperature surface. HCAs have been shown to cause DNA mutation, and may be a factor in the development of certain cancers. - Polycyclic Aromatic Hydrocarbons (PAHs) form in smoke that's produced when fat from the meat ignites or drips on the hot coals of the grill. PAH exposure is also believed to be linked to certain cancers. 3. FOOD TECHNOLOGY: EFFECT OF FOOD PROCESSING - The freshness, appearance, and nutritive value of foods changes when they are stored for long time. - The conversion of raw food materials into the acceptable food product by a variety of means is referred to as food processing. - The techniques followed include: dehydration, freezing, heating at high temperatures, exposure to radiation (i.e. irradiation), fermentation, chemical preservation etc. - Processing of food has advantages and disadvantages both. We know that it results into desirable changes like enhancement of flavours, improvement of texture, and increase in shelf life etc. However, it may lead to some undesirable changes too. These include changes in colour, flavour, nutritional properties and development of toxicity. 3. FOOD TECHNOLOGY: EFFECT OF FOOD PROCESSING Effects on Vitamins: - Dehydration (i.e. removal of water under controlled conditions) can result in decrease of vitamin levels. - Heating at high temperatures results into a number of changes:  For example, the heating process employed in industry for the sterilization of milk- based formulations greatly reduces their vitamin B6 content, thiamin may be lost to the extent of 30-50%.  Baking of cereals and cereal products also cause loss of B-group vitamins to different extent.  The vitamin like vitamin A or vitamin B do not get affected by frying of egg. Vitamin A is relatively stable to heat in the absence of oxygen. Losses may occur at high temperatures in the presence of oxygen.  Vitamin D is extremely stable and little or no loss is experienced in processing and storage. Vitamin D in milk is not affected by pasteurization, boiling or sterilization. - Frozen storage: of milk or butter also had little or no effect on vitamin D levels.