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28-398: Bran is the hard outer layer of cereal grains. Bran may also refer to: Bran Bran , also known as miller's bran , is the component of a cereal grain consisting of the hard layers - the combined aleurone and pericarp - surrounding the endosperm . Corn (maize) bran also includes the pedicel (tip cap). Along with the germ , it is an integral part of whole grains , and

56-461: A bland flavor, at least 200 °C (392 °F) smoke and 315 °C (599 °F) flash points, with maximums of 0.1% free fatty acids and 3% linolenic acid. Those oils with higher linolenic fractions are avoided due to polymerization or gumming marked by increases in viscosity with age. Olive oil resists thermal degradation and has been used as a frying oil for thousands of years. All oils degrade in response to heat, light, and oxygen. To delay

84-906: A link between the consumption of high amounts of trans fat and coronary heart disease, and possibly some other diseases. The United States Food and Drug Administration (FDA) , the National Heart, Lung and Blood Institute and the American Heart Association (AHA) all have recommended limiting the intake of trans fats. In the US, trans fats are no longer "generally recognized as safe", and cannot be added to foods, including cooking oils, without special permission. Heating, as well as heating vessels rapidly change characteristics of cooking oil. Oils that are healthy at room temperature can become unhealthy when heated above certain temperatures, especially when heating repeatedly. The toxic risk

112-456: A source using a mechanical press with minimal heat. Cold-pressed oils are extracted under a controlled temperature setting usually below 105 °C (221 °F) intended to preserve naturally occurring phytochemicals, such as polyphenols , tocotrienols , plant sterols and vitamin E which collectively affect color, flavor, aroma and nutrient value. Cooking oil extraction and refinement are separate processes. Extraction first removes

140-407: A year , while those high in polyunsaturated fats, such as soybean oil , keep about six months. Rancidity tests have shown that the shelf life of walnut oil is about 3 months, a period considerably shorter than the best before date shown on labels. By contrast, oils high in saturated fats, such as avocado oil , have relatively long shelf lives and can be safely stored at room temperature , as

168-699: Is also a source of phytic acid , an antinutrient that prevents nutrient absorption. The high oil content of bran makes it subject to rancidification , one of the reasons that it is often separated from the grain before storage or further processing. Bran is often heat-treated to increase its shelf life. Rice bran is a byproduct of the rice-milling process (the conversion of brown rice to white rice ), and it contains various antioxidants . A major rice bran fraction contains 12%–13% oil and highly unsaponifiable components (4.3%). This fraction contains tocotrienols (a form of vitamin E ), gamma-oryzanol , and beta-sitosterol ; all these constituents may contribute to

196-1215: Is an aerosol of cooking oil. While consumption of small amounts of saturated fats is common in diets, meta-analyses found a significant correlation between high consumption of saturated fats and blood LDL concentration, a risk factor for cardiovascular diseases . Other meta-analyses based on cohort studies and on controlled, randomized trials found a positive, or neutral, effect from consuming polyunsaturated fats instead of saturated fats (a 10% lower risk for 5% replacement). Mayo Clinic has highlighted certain oils that are high in saturated fats, including coconut , palm oil and palm kernel oil . Those having lower amounts of saturated fats and higher levels of unsaturated (preferably omega-3) fats like olive oil, peanut oil, canola oil, soy and cottonseed oils are generally healthier. The US National Heart, Lung and Blood Institute urged saturated fats be replaced with polyunsaturated and monounsaturated fats, listing olive and canola oils as sources of healthier monounsaturated oils while soybean and sunflower oils as good sources of polyunsaturated fats. One study showed that consumption of non-hydrogenated unsaturated oils like soybean and sunflower

224-561: Is called yellow grease, recycled vegetable oil (RVO), used vegetable oil (UVO), or waste vegetable oil (WVO). Grease traps or interceptors collect fats and oils from kitchen sinks and floor drains. The result is called brown grease, and unlike yellow grease its severe contaminants make it much harder to recycle. Gutter oil and trench oil are terms used in China to describe recycled oil processed to resemble virgin oil, but containing toxic contaminants and sold illegally for cooking; its origin

252-690: Is linked to oxidation of fatty acids and fatty acids with higher levels of unsaturation are oxidized more rapidly during heating in air. So, when choosing a cooking oil, it is important to match the oil's heat tolerance with the temperature which will be used. and to change frying oil a few times per week. Deep-fat frying temperatures are commonly in the range of 170–190 °C (338–374 °F), less commonly, lower temperatures ≥ 130 °C (266 °F) are used. Palm oil contains more saturated fats than canola oil, corn oil, linseed oil, soybean oil, safflower oil, and sunflower oil. Therefore, palm oil can withstand deep frying at higher temperatures and

280-502: Is marked by "a continuous wisp of smoke". It is the temperature at which an oil starts to burn, leading to a burnt flavor in the foods being prepared and degradation of nutrients and phytochemicals characteristic of the oil. Above the smoke point are flash and fire points. The flash point is the temperature at which oil vapors will ignite but are not produced in sufficient quantities to stay lit. The flash point generally occurs at about 275–330 °C (527–626 °F). The fire point

308-445: Is often produced as a byproduct of milling in the production of refined grains . Bran is highly nutritious, but is difficult to digest due to its high fiber content; its high fat content also reduces its shelf life as the oils/fats are prone to becoming rancid. As such, it is typically removed from whole grain during the refining process - e.g. in processing wheat grain into white flour, or refining brown rice into white rice. Bran

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336-458: Is often used to enrich breads (notably muffins ) and breakfast cereals , especially for the benefit of those wishing to increase their intake of dietary fiber . Bran may also be used for pickling ( nukazuke ) as in the tsukemono of Japan . Rice bran in particular finds many uses in Japan, where it is known as nuka ( 糠 ; ぬか ). Besides using it for pickling, Japanese people add it to

364-908: Is preferable to the consumption of palm oil for lowering the risk of heart disease . Cashew oil and other nut-based oils do not present a danger to persons with a nut allergy , because oils are primarily lipids, and allergic reactions are due to surface proteins on the nut. The seeds of most cultivated plants contain higher levels of omega-6 fatty acids than omega-3 , with some notable exceptions. Growth at colder temperatures tends to result in higher levels of omega-3 fatty acids in seed oils. Unlike other dietary fats, trans fats are not essential , and they do not promote good health. The consumption of trans fats increases one's risk of coronary heart disease by raising levels of LDL cholesterol and lowering levels of HDL cholesterol. Trans fats from partially hydrogenated oils are more harmful than naturally occurring oils. Several large studies indicate

392-457: Is present in cereal grain, including rice , corn (maize) , wheat , oats , barley , rye , and millet . Bran is not the same as chaff , which is a coarser, scaly material surrounding the grain, but does not form part of the grain itself, and which is indigestible by humans. Bran is particularly rich in dietary fiber and essential fatty acids , and contains significant quantities of starch , protein , vitamins , and dietary minerals . It

420-614: Is resistant to oxidation compared to high-polyunsaturated vegetable oils. Since the 1900s, palm oil has been increasingly added into food by the global commercial food industry because it remains stable in deep frying, or in baking at very high temperatures, and for its high levels of natural antioxidants, though the refined palm oil used in industrial food has lost most of its carotenoid content (and its orange-red color). The following oils are suitable for high-temperature frying due to their high smoke point : Less aggressive frying temperatures are frequently used. A quality frying oil has

448-428: Is the temperature at which hot oil produces sufficient vapors they will catch on fire and burn. As frying hours increase, all these temperature points decrease. They depend more on an oil's acidity than fatty-acid profile. The smoke point of cooking oils varies generally in association with how oil is refined: a higher smoke point results from removal of impurities and free fatty acids. Residual solvent remaining from

476-493: Is to put it in a sealed non-recyclable container and discard it with regular garbage. Placing the container of oil in the refrigerator to harden also makes disposal easier and less messy. Cooking oil can be recycled. It can be used in animal feed, soap, make-up, clothes, rubber, detergents, directly as fuel, and to produce biodiesel . In the recycling industry, used cooking oil recovered from restaurants and food-processing industries (typically from deep fryers or griddles )

504-507: Is useful as feed for poultry and other livestock , as part of a balanced ration with other inputs. Wheatings, a milling byproduct comprising mostly bran with some pieces of endosperm also left over, are included in this category. Bran was found to be the most successful slug deterrent by BBC's TV programme Gardeners' World . It is a common substrate and food source used for feeder insects, such as mealworms and waxworms . Wheat bran has also been used for tanning leather since at least

532-424: The water when boiling bamboo shoots , and use it for dish washing . In Kitakyushu City, it is called jinda and used for stewing fish, such as sardines . Rice bran is stuck to the surface of commercial ice blocks to prevent them from melting. Bran oil may be also extracted for use by itself for industrial purposes (such as in the paint industry), or as a cooking oil , such as rice bran oil . Wheat bran

560-630: The 16th century. As with cereal fibers and whole grain consumption, bran is under preliminary research for the potential to improve nutrition and affect chronic diseases. Commonly, bran is heat-treated with the intention of slowing undesirable rancidification, but a 2003 study of heat-treatment of oat bran found a complex pattern whereby increasingly intense heat treatment reduced the development of hydrolytic rancidity and bitterness with time, but increased oxidative rancidity. The authors recommended that heat treatment should be sufficient to achieve selective lipase inactivation, but not so much as to render

588-437: The following refinement processes (in any combination): Filtering, a non-chemical process which screens out larger particles, could be considered a step in refinement, although it does not alter the state of the oil. Most large-scale commercial cooking oil refinement will involve all of these steps in order to achieve a product that's uniform in taste, smell and appearance, and has a longer shelf life. Cooking oil intended for

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616-428: The health food market will often be unrefined, which can result in a less stable product but minimizes exposure to high temperatures and chemical processing. Proper disposal of used cooking oil is an important waste-management concern. Oil can congeal in pipes, causing sanitary sewer overflow . Because of this, cooking oil should never be dumped in the kitchen sink or in the toilet bowl. The proper way to dispose of oil

644-437: The low polyunsaturated fat content facilitates stability. Cooking oils are composed of various fractions of fatty acids . For the purpose of frying food, oils high in monounsaturated or saturated fats are generally popular, while oils high in polyunsaturated fats are less desirable. High oleic acid oils include almond, macadamia, olive, pecan, pistachio, and high-oleic cultivars of safflower and sunflower. The smoke point

672-457: The lowering of the plasma levels of the various parameters of the lipid profile. Rice bran also contains a high level of dietary fiber ( beta-glucan , pectin , and gum). It also contains ferulic acid , which is also a component of the structure of nonlignified cell walls. Some research suggests, though, inorganic arsenic is present at some level in rice bran. One study found the levels to be 20% higher than in contaminated drinking water. Bran

700-468: The oil, typically from a seed, nut or fruit. Refinement then alters the appearance, texture, taste, smell, or stability of the oil to meet buyer expectations. There are three broad types of oil extraction: In large-scale industrial oil extraction you will often see some combination of pressing, chemical extraction and/or centrifuging in order to extract the maximum amount of oil possible. Cooking oil can either be unrefined, or refined using one or more of

728-556: The onset of rancidity , a blanket of an inert gas , usually nitrogen, is applied to the vapor space in the storage container immediately after production – a process called tank blanketing . In a cool, dry place, oils have greater stability, but may thicken, although they will soon return to liquid form if they are left at room temperature. To minimize the degrading effects of heat and light, oils should be removed from cold storage just long enough for use. Refined oils high in monounsaturated fats, such as macadamia oil , keep up to

756-627: The polar lipids oxidizable upon prolonged storage. Cooking oil Cooking oil is typically a liquid at room temperature, although some oils that contain saturated fat, such as coconut oil , palm oil and palm kernel oil are solid. There are a wide variety of cooking oils from plant sources such as olive oil , palm oil , soybean oil , canola oil ( rapeseed oil), corn oil , peanut oil , sesame oil , sunflower oil and other vegetable oils , as well as animal-based oils like butter and lard . Oil can be flavored with aromatic foodstuffs such as herbs , chilies or garlic . Cooking spray

784-415: The refining process may decrease the smoke point. It has been reported to increase with the inclusion of antioxidants (BHA, BHT, and TBHQ). For these reasons, the published smoke points of oils may vary. Oils are extracted from nuts, seeds, olives, grains or legumes by extraction using industrial chemicals or by mechanical processes. Expeller pressing is a chemical-free process that collects oils from

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