Antioxidants Foods

Antioxidants preservatives in food

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.

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 widely used as ingredients in dietary supplements in the hope of maintaining health and preventing diseases such as cancer and coronary heart disease. Although initial studies suggested that antioxidant supplements might promote health, later large clinical trials did not detect any benefit and suggested instead that excess supplementation may be harmful. In addition to these uses of natural antioxidants in medicine, these compounds have many industrial uses, such as preservatives in food and cosmetics and preventing the degradation of rubber and gasoline.

Antioxidants are used as food additives to help guard against food deterioration. Exposure to oxygen and sunlight are the two main factors in the oxidation of food, so food is preserved by keeping in the dark and sealing it in containers or even coating it in wax, as with cucumbers. However, as oxygen is also important for plant respiration, storing plant materials in anaerobic conditions produces unpleasant flavors and unappealing colors. Consequently, packaging of fresh fruits and vegetables contains an 8% oxygen atmosphere. Antioxidants are an especially important class of preservatives as, unlike bacterial or fungal spoilage, oxidation reactions still occur relatively rapidly in frozen or refrigerated food. These preservatives include natural antioxidants such as ascorbic acid and tocopherols , as well as synthetic antioxidants such as propyl gallate , tertiary butylhydroquinone , butylated hydroxyanisole and butylated hydroxytoluene .

The most common molecules attacked by oxidation are unsaturated fats; oxidation causes them to turn rancid. Since oxidized lipids are often discolored and usually have unpleasant tastes such as metallic or sulfurous flavors, it is important to avoid oxidation in fat-rich foods. Thus, these foods are rarely preserved by drying; instead, they are preserved by smoking, salting or fermenting. Even less fatty foods such as fruits are sprayed with sulfurous antioxidants prior to air drying. Oxidation is often catalyzed by metals, which is why fats such as butter should never be wrapped in aluminium foil or kept in metal containers. Some fatty foods such as olive oil are partially protected from oxidation by their natural content of antioxidants, but remain sensitive to photooxidation. Antioxidant preservatives are also added to fat-based cosmetics such as lipstick and moisturizers to prevent rancidity.

Antioxidant fruits vegetables

Fresh or frozen fruits and vegetables are both good, and contrary to common thought, frozen produce is just as nutrient dense as fresh produce, while dried produce is often sweetened, causing some of the nutrients to be broken down. Studies have shown produce consumption is effective in reducing cancers, especially in the gastrointestinal tract, lowering cancer rates by 22% and mortality to dietary related cancer by 11%. Berries have been causing a lot of commotion and promise in the world of cancer research. The darker the berry, the better in terms of being more packed with nutrients that is better at warding off cancer. Antioxidant fruits vegetables Research has been putting the spot light on black raspberries and their ability to reduce oxidative stress and gastroesophageal reflux disease, each of which causes damage to the esophageal cells. Close runner-ups to the black raspberry are blueberries, blackberries, strawberries, and cranberries. These berries are high in vitamin C, fiber, and ellagic acid, which can prevent skin cancer. In addition to these nutrients, the American Association for Cancer Research found that berries are extremely high in polyphenol phytochemicals, and some research is suggesting that these phytochemicals are what is inhibiting tumor growth, more so than vitamins and minerals. Antioxidant fruits and vegetables phytochemicals have the ability to interfere with tumor development, probably due to their natural job of protecting plants and their structures, as well as maintaining their vibrant colors (2007). Beta-carotene and lycopene are two prevalent nutrients that have shown a lot of promise in their capabilities to slow tumor growth.

Antioxidant fruits

Natural antioxidant foods are fruits, vegetables, cereals, legumes, nuts and seeds. The best way to ensure adequate intake of the antioxidants is to eat a variety of fruits and vegetables through a diet consisting of 5 to 8 servings of fruits and vegetables per day.

Antioxidant fruits ensure adequate intake of the antioxidants is to eat a variety of fruits and vegetables through a diet consisting of 5 to 8 servings of fruits and vegetables per day.

Antioxidant fruits may also enhance immune defense and therefore lower the risk of cancer and infection. Antioxidants are widely used as ingredients in dietary supplements in the hope of maintaining health and preventing diseases such as cancer and coronary heart disease. Its important to include Antioxidant fruits in our daily diet.

Antioxidants in food

Vitamins

Vitamin A (retinol), also synthesized by the body from beta-carotene, protects dark green, yellow and orange vegetables and fruits from solar radiation damage, and is thought to play a similar role in the human body. Carrots, squash, broccoli, sweet potatoes, tomatoes (which gain their color from the compound lycopene), kale, mangoes, oranges, seabuckthorn berries, wolfberries (goji), collards, cantaloupe, peaches and apricots are particularly rich sources of beta-carotene, the major provitamin A carotenoid.

Vitamin C (ascorbic acid) is a water-soluble compound that fulfills several roles in living systems. Important sources include citrus fruits (such as oranges, sweet lime, etc.), green peppers, broccoli, green leafy vegetables, black currants, strawberries, blueberries, seabuckthorn, raw cabbage and tomatoes. Linus Pauling was a major advocate for its use.

Vitamin E, including tocotrienol and tocopherol, is fat soluble and protects lipids. Sources include wheat germ, seabuckthorn, nuts, seeds, whole grains, green leafy vegetables, kiwifruit, vegetable oil, and fish-liver oil. Alpha-tocopherol is the main form in which vitamin E is consumed. Recent studies showed that some tocotrienol isomers have significant anti-oxidant properties.

Vitamin cofactors and minerals

Coenzyme Q10
Manganese, particularly when in its +2 valence state as part of the enzyme called superoxide dismutase (SOD).
Iodide

Antioxidant food sources

Many common foods are good sources of antioxidants. In the list of foods given below, rich in anti-oxidants usually means at least a ORAC rating of 1000 per 100 g. A typical apple or pear weighs around 200 g and hence 200 g can be considered as the serving size.

Spices, herbs, essential oils and cocoa are rich in anti-oxidant properties but the serving size is too small to be the top-contributors of anti-oxidants. Typical spices high in anti-oxidants are cinnamon, oregano, turmeric, cumin, parsley, basil, curry powder, mustard seed, ginger, pepper, chili powder, paprika, garlic, coriander, onion and cardamom. Typical herbs are sage, thyme, marjoram, tarragon, peppermint, oregano, savory, basil and dill weed. Chocolate is rich in cocoa.

Dried fruits are a good source of anti-oxidants by weight/serving size as the water has been removed making the ratio of anti-oxidants higher. Typical dried fruits are pears, apples, plums, peaches, raisins, figs and dates. Dried raisins are high in polyphenol count. Red wine is high in total anti-oxidants count as well as polyphenol count.

Sorghum bran, cocoa powder, and cinnamon are rich sources of procyanidins, which are very large compounds found in many fruits and some vegetables and that have been shown to be beneficial for health in humans. Because of the large size of these compounds, the amount that is actually absorbed into the body is thought to be low. These compounds can be degraded by bacteria in the gastrointestinal tract. Crude rice bran and other cereals like corn-flakes, oats and granola are also a good source of anti-oxidants.

Nuts are a rich source of anti-oxidants. Typical nuts are pecans, walnuts, hazelnuts, pistachio, almonds, cashew nuts, macadamia nuts and peanut butter.

Fleshy fruits like cranberries, blueberries, plums, peaches, blackberries, raspberries, apples, strawberries, red currants, figs, cherries, gooseberry (not to be confused with Indian gooseberry which also has strong claims), pears, guava, peaches, oranges, apricots, mango, grape juice and pomegranate juice also rated highly on the ORAC scale.

Typical cooked vegetables rich in anti-oxidants are artichokes, cabbage, broccoli, asparagus, avocados, beetroot, radish, potato and raw lettuce and frozen spinach.