...Antioxidant From Wikipedia, the free encyclopedia Jump to: navigation, search An antioxidant is a molecule capable of slowing or preventing the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons from a substance to an oxidizing agent. Oxidation reactions can produce free radicals, which start chain reactions that damage cells). Antioxidants terminate these chain reactions by removing free radical intermediates, and inhibit other oxidation reactions by being oxidized themselves. As a result, antioxidants are often reducing agents such as thiols, ascorbic acid or polyphenols.[1] Although oxidation reactions are crucial for life, they can also be damaging; hence, plants and animals maintain complex systems of multiple types of antioxidants, such as glutathione, vitamin C, and vitamin E as well as enzymes such as catalase, superoxide dismutase and various peroxidases. Low levels of antioxidants, or inhibition of the antioxidant enzymes, cause oxidative stress and may damage or kill cells. As oxidative stress might be an important part of many human diseases, the use of antioxidants in pharmacology is intensively studied, particularly as treatments for stroke and neurodegenerative diseases. However, it is unknown whether oxidative stress is the cause or the consequence of disease. Antioxidants are also widely used as ingredients in dietary supplements in the hope of maintaining health and preventing diseases such as cancer...
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...bind to its inhibitor, the substrate or neither. They are unable to bind to both at the same time. This inhibition competes with the substrate for binding sites on the enzymes. However, a competitive inhibitor is reversible if the concentration of the substrate is raised to high levels while the inhibitor is constant. Noncompetitive inhibitors do not compete for its position in the active site. It decreases the activity of the enzyme and binds equally even if it’s bound to the substrate or not. This causes the conformations of the protein to change. With Noncompetitive inhibitors the inhibitors can become unbound so they are reversible (Enzymes Can Be Inhibited by Specific Molecules). To further test the effect of the results, a fruit such as bananas could be tested to completely determine PTU’s inhibition. Catechol oxidase is an enzyme that catalyzes the reactions between...
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...this experiment, ascorbic acid content of apple fruit juice in different conditions was determined by indophenol dye method. The reduced form of ascorbic acid (which is also known as Vitamin C) were determined by this procedure. This was because ascorbic acid is a strong reducing agent. Ascorbic acid was extracted and titration performed in presence of metaphosphoric acid-acetic solution. When titrated with fixed amount of 2, 6-dichlorophenolindophenol red indophenol dye, it was oxidized to dehydroascorbic acid (Kumar et al. 2013). At the end of titration, the dye was reduced to a colourless compound. Thus, the reaction with end point was determined easily by observing the colour change in order to allow the calculation of ascorbic acid concentration. Based on the calculation of my group results, the molarity of standardeized 2, 6-dichlorophenolindophenol was 8.0425×10-4M, the molarity of fresh fruit juice was 4.4234×10-3M, the molarity of bubbling fruit juice was 4.1821×10-3M and the molarity of bubbling and copper sulphate (CuSO4) fruit juice was 1.8095×10-3M. From the sample results, the mean of the molarity of standardeized 2, 6-dichlorophenolindophenol was 7.9825×10-4M ± 5.6551×10-6M , the mean of the molarity of fresh fruit juice was 4.3426×10-3M ± 4.9089×10-9M, the molarity of bubbling fruit juice was 4.0663×10-3M ± 2.9212×10-8M and the molarity of bubbling and CuSO4 fruit juice was 1.8095×10-3M ± 4.2885×10-9M. Fresh fruit had the highest concentration of ascorbic acid...
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...de Chimie Générale et Organique, Faculté Universitaire des Sciences Agronomiques de Gembloux, passage des Déportés 2, 5030 Gembloux, Belgique. Abstract: Effects of heating on some quality characteristics of date seed oil from two cultivars (Deglet Nour and Allig) has been investigated using an accelerated test in a Rancimat system. Fatty acid, viscosity, absorptivity at 232 and 270 nm, colour and total melting enthalpy of Deglet Nour seed oil were less changed compared to that of Allig seed oil, because the former contained a higher amount of total phenolic compounds (526 µg/g against 215 µg/g) and a lower content of unsaturated fatty acids. Viscosity and absorptivity at 232 nm and at 270 nm increased rapidly after reaching the oxidation induction time. Differential scanning calorimetry melting profiles of date seed oils were also changed after heating in the Rancimat. Melting enthalpies seemed to be constant during the initial stages of Rancimat treatment and then reduced after the induction time was reached. The obtained data shows that date seed oils were resistant to thermal treatment during a long period (~30-40 h). This may indicate that they could bear thermal...
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...Preservation using natural products is associated with the presence of antioxidants,antimicrobial,antifungal or dehydrating properties. Fresh meatballs are made from meats that have not been previously cured,they are made from ground meat,either pork,beef or veal. Meatballs are however susceptible to microbial spoilage and auto-oxidation. The artificial chemical preservatives used in meatball preservation.eg sodium metabisulphite may be replaced by natural extracts such as Tamarind and Ziziphus extracts which have both antimicrobial and anti-oxidant properties. The extracts will be obtained from Tamarind andZiziphusseeds.The seeds will be dried and ground into powder followed by liquid/liquid extraction. The extraction was carried out by 400ml ethyl acetate and water for 100grams from each sample. The fresh meatballs will be processed in the JKUAT meat workshop using the correct recipe. Fresh meatballs batch with no preservative will act as the control. Another batch with sodium metabisulphite and finally with the seed extracts. The processed fresh meatballs will be stored at 40c and at 250c and the samples analyzed within a staggered period of 4 weeks for auto-oxidation,microbial load and colourchanges.The obtained results will be recorded, analyzed and presented appropriately by use of correct scientific statistical methods e.g. graphs. 1.0 INTRODUCTION The consumption of ready-to-eat meals has grown, mainly because modern leaving allows little time to prepare meals. Despite the sophisticated...
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...Within the last twenty years or so; Patrick Quillin, PhD, RD, CNS, author of Beating Cancer with Nutrition, and other research has shed new light on diet playing a role in the prevention and potential reversal of cancer. Nutrition and diet play a substantial role in the development and preservation of the human immune system and overall health of the human body on the cellular level. However, the correlation between diet and cancer is unclear despite research being conducted in the field of nutritional oncology. Though significant progress has been realized in the treatment of cancers through modern technological advances in medicine, prevention and mitigation of cancer lay within nutrition, more specifically a natural diet consisting of fruits and vegetables, which contain antioxidants and phytonutrients. Background Cancer is a collective term describing uninhibited cell propagation in various parts of the human body [1]. This process is called carcinogenesis (literally means “cancer creation”). Once propagated, the cancer can spread and cause death in a timely manner. Cancer occurs via mutations in the genetic code that can occur in a variety of cells in the human body. Mutations of this sort are believed to be the result of oxidative stress. In the human body oxidative stress occurs when there is a disparity between free radicals and antioxidants, thus compromising the body’s ability to cleanse itself. In fact, one of the more detrimental characteristics of oxidative stress...
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...than radical lipids. The second function is a secondary function of anti-oxidants, which slows the rate of auto-oxidation with a variety of mechanisms beyond the auto-oxidation mechanism of chain termination by radical conversion of lipids to form more stable 2. Antioxidants are important dietary nutrients. Antioxidants are substances in food which prevent damage to your body’s cells and tissues caused by free radicals. It’s important to keep free radicals in check, as they may contribute to aging, cancer and chronic diseases such as heart disease and Parkinson’s disease. Vitamin C - Citrus fruits and their juices, berries, dark green vegetables (spinach, asparagus, green peppers, brussel sprouts, broccoli, watercress, other greens), red and yellow peppers, tomatoes and tomato juice, pineapple, cantaloupe, mangos, papaya and guava. Vitamin E - Vegetable oils such as olive, soybean, corn, cottonseed and safflower, nuts and nut butters, seeds, whole grains, wheat, wheat germ, brown rice, oatmeal, soybeans, sweet potatoes, legumes (beans, lentils, split peas) and dark leafy green vegetables. Selenium - Brazil nuts, brewer’s yeast, oatmeal, brown rice, chicken, eggs, dairy products, garlic, molasses, onions, salmon, seafood, tuna, wheat germ, whole grains and most vegetables. Beta Carotene - Variety of dark orange, red, yellow and green vegetables and fruits such as broccoli, kale, spinach, sweet potatoes, carrots, red and...
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...practice of preserving for fun. However, Food preservation is the process by which certain foods like vegetables and fruits are preserved from the growth of bacteria, yeast, fungi and other micro-organisms which causes food blemish. Food preservation practice should be done in a hygienic manner to observe the health of the people for it can cause food borne illness. The preservation of food should not affect the colour, taste or the texture of the food. However, there are several reasons why we preserve food in our society today. We preserve food for personal satisfaction, helps in acquiring more skills on how to reduce waste products, prepare for emergencies, it makes transportation of food and it’s environmentally friendly. There are different methods of food preservation and storage which differ from traditional techniques to industrial or modern techniques. Methods of food preservation There are many process designed to preserve food which involve a number of preservation methods. There are two methods of preserving food; the traditional and modern methods. In ancient times food was preserved in many ways including; freezing, salt, drying, sugar, smoking, drying, refrigeration, lye, pickling, jugging, jellying, canning and bottling, fermentation and curing. Drying method of preserving food was used to slow down the decay of food products such as vegetables and fruits using the power of the sun. It is said to be the oldest method of dehydration. For instance, in the Middle Eastern...
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...industries and homes across the globe result to using preservation, freezing, and blanching to prevent the loss of quality and oxidation reactions that occur. I chose to experiment with the common white button mushroom, also known as Agaricus bisporus, due to my grandparents' familiarity with mushrooms back on their farm in China. As a functional fungus, the Agaricus bisporus can serve as a good source of fiber full of vitamins and minerals and contain medicinal properties with anti-inflammatory benefits for the skin and body (Feeney 1130S)....
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...CHEMISTRY CHEMISTRY (CLASSES XI–XII) Rationale Higher Secondary Stage is the most crucial stage of school education because at this stage specialised discipline based, content oriented courses are introduced. Students reach this stage after 10 years of general education and opt for Chemistry with a purpose of mostly for pursuing their career in basic sciences or professional courses like medicines, engineering, technology and studying courses in applied areas of science and technology at tertiary level. Therefore, at this stage, there is a need to provide learners with sufficient conceptual background of Chemistry, which will make them competent to meet the challenges of academic and professional courses after the higher secondary stage. National Curriculum Framework for School Education – 2005 recommends a disciplinary approach with appropriate rigour and depth with the care that syllabus is not heavy and at the same time it is comparable to the international level. It emphasizes a coherent focus on important ideas within the discipline that are properly sequenced to optimize learning. It recommends that theoretical component of Higher Secondary Science should emphasize on problem solving methods and the awareness of Syllabus for Secondary and Higher Secondary Levels 22 historical development of key concepts of science be judiciously integrated into content. The present exercise of syllabus development in Chemistry at Higher Secondary Stage is based on this framework...
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...healthily and have the food still be affordable. The article compares food from supermarkets and food from gourmet markets, which is supposedly better for you. It shows that supermarket food is often better for you, if not just as healthy as the more expensive gourmet market food. 3. The process of blanching food keeps it healthy because it deactivates enzymes in the food that could degrade its color, flavor, and nutrient content. Blanching can also increase the fibrous content in food by concentrating it, which helps human digestion. 4. Canned food can be good for you. The food is first heated to a temperature sufficient to kill all of the bacteria. It is then sealed in airtight containers that prevent oxidation. In peeling or blanching foods before freezing them, oxidation is caused. 5. Eating meat can be good for you. Meat is full of protein, and eating it is fine as long as the serving size is four to six ounces. As long as the meat is not deep fried from fast food places, it is healthy. 6. Canned fish can be good for you for many reasons. Canning food does not affect protein content, which makes the food good sources of nutrition. Canned fish is just as nourishing as catching your own fish. It is also very easy to prepare. 7. We can still eat ice cream and lead healthy lives. The main problem with ice cream is the amount consumed. There are benefits to ice cream, though. There is a good amount of protein and calcium in it, as well as walnuts, almonds, cashews, and...
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...berasal dari aktivitas biologi makhluk hidup, industri perakitan, industri pengolahan suatu bahan, sisa-sisa penggunaan suatu barang, dan lain-lain. Limbah yang dihasilkan dari industri kimia biasanya mengandung senyawa-senyawa berbahaya yang dapat merusak keseimbangan ekosistem perairan. Hal tersebut dikarenakan bahan baku maupun sisa-sisa hasil produksi pada industri kimia tidak dapat diuraikan oleh mikrobiologi dan cenderung bersifat beracun, sehingga diperlukan penanganan khusus untuk bahan-bahan tertentu. Penanganan tersebut dapat berupa pengolahan primer, sekunder maupun tersier. Dalam penelitian ini yang dikaji adalah limbah pewarna tekstil, dimana penanganannya memerlukan pengolahan secara tersier, dengan menggunakan metode Advanced Oxidation Process dengan UV/H2O2. Tujuan penelitian ini adalah mengkaji kemungkinan pengolahan limbah pewarna tekstil non-biodegradable dengan proses H2O2/UV di dalam bubble column photoreactor, mencari pengaruh kondisi operasi seperti konsentrasi H2O2 dan pH serta waktu tinggal limbah dalam reaktor) terhadap warna, pH, dan BOD/COD dari limbah hasil pengolahan. Manfaat penelitian ini adalah meningkatkan kualitas air buangan dari limbah industri tekstil, memberikan tambahan pengetahuan tentang pengolahan limbah tekstil, memberikan alternatif baru dari pengolahan limbah tekstil . Penelitian yang dilakukan hanya meliputi percobaan pendahuluan dan percobaan utama yaitu pengolahan limbah dengan 4 variasi konsentrasi H2O2 pada rentang...
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...indicated that the pineapple juice with sugar concentration of 20 Brix, seeded with 106 cells of Saccharomyces cerevisiae (LAS01) for alcoholic fermentation for 4 days and afterwards seeded with 106 cells of Acetobacter sp. resulted in 4.5 acetic degree vinegar at Brix 5.3% and pH 2.8 for 23 to 25 days. The study of glucose tolerance of the strain of Acetobacter sp. showed that the growth of acetic bacteria was important in a juice with high concentration of sugar. However, the concentration of ethanol did not effect on the acetic bacteria growth. These results enabled on one hand to improve the manufacturing technology of vinegar from fruits and on the other hand to produce a starter of yeast and acetic bacteria strains for this production. | | INTRODUCTIONDeveloping countries, including tropical African countries, produce huge quantities of fruits and vegetables;...
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...very magnetic solid. Iron is very strong and malleable. It has a very high melting point of 2800 °F and a boiling point of 5182 °F. (Winter, 1993-2012) The atomic mass of Iron is 55.87 and has a density of 7.87g/cc. It is in the transition metal category of the periodic table. Iron has very high oxidation properties and when exposed to air will react with the oxygen and form rust. The second chemical element that will be discussed is potassium (K). Potassium’s atomic number is 19, its atomic weight is 39.0983. It has a boiling point of 146.08 °F, a melting point of 1398 °F and a density of856 kg m-3. (Winter, Web Elements, 1993-2012) Potassium like iron is a silvery white color and is in the alkali metal group on the periodic table and oxidizes very quickly. It is very reactive and the least dense known metal. Importance in Nature Iron is found in nature and is rather abundant and is formed in the Earth’s crust. It is used to create other metals that are used for building, iron ore, steele, wrought iron and cast iron. Iron also has an important role in the human body and biology. It will combine with molecular oxygen in hemoglobin and myoglobin. Iron also aids in the oxidation and reduction in plants and animals. (Bentor, 1996-2012)...
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...Study Guide Exam 1 Bring a scantron #886 and a #2 pencil for the exam. Course Materials Covered: The exam includes materials from the Brown text, lecture and lab experiments and conclusions. Brown text: • Chapter 1 • Chapter 3: Water • Chapter 5: Food Preparation Basics • Chapter 13: Vegetables (excluding legumes) • Chapter 14: Fruits • Knife Safety Handout in manual Vocabulary words: sensory criteria, taste, flavor, aroma, volatile molecules, olfactory, gustatory, consistency, astringency, density, bioengineering, biotechnology, melting point, boiling point, freezing point, latent heat, viscosity, poach, simmer, boil, slice, shred, dice, mince, peel, standing time, fractional measure, liquid measure, flavoring, seasoning, induction, conduction, convection, radiation, oxidation, drupe, pomes, carotenoids, chlorophyll, anthocyanin, anthoxanthin, enzymatic browning, phenolic compounds, polyphenolase, cruciferous, phytochemicals, pectin., albedo. 1. What are the five major criteria for selecting food explained in the text? Examples? 2. What are the five taste stimuli? Examples? 3. What is taste? 4. What is flavor? 5. What is subjective evaluation of foods? What are examples of tests used? 6. What is objective evaluation of food? What are examples of tests used? 7. What are the functions of water in the preparation of food? 8. What are examples of moist heat preparation? 9. What are examples of...
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