Peanut oil, also known as groundnut oil or arachis oil, is a mild tasting vegetable oil derived from peanuts. The oil is available in refined, unrefined, cold pressed, and roasted varieties, the latter with a strong peanut flavor and aroma, analogous to sesame oil.
It is often used in Chinese, South Asian and Southeast Asian cuisine, both for general cooking, and in the case of roasted oil, for added flavor. Peanut oil has a high smoke point relative to many other cooking oils, so is commonly used for frying foods. Its major component fatty acids are oleic acid (46.8% as olein), linoleic acid (33.4% as linolein), and palmitic acid (10.0% as palmitin). The oil also contains some stearic acid, arachidic acid, arachidonic acid, behenic acid, lignoceric acid and other fatty acids.
Antioxidants such as vitamin E are sometimes added, to improve the shelf life of the oil.
Cold pressed peanut oil has deep yellow color with pleasant nutty aroma and sweet taste. Refined oil has light yellow and has the neutral taste. However, refining makes it virtually devoid of impurities and allergens. Its specific gravity @ 25 °C is 912-0.920, Iodine value-84–100, and saponification value-185–195.
Peanut oil is high in energy; 100 g oil provides 884 calories.
It is one of the cooking oils with a high smoke point; 450 °F. The property can be employed in setting oil temperatures while deep-frying food items.
Peanut oil has very good lipid profile. It has saturated, monounsaturated and polyunsaturated (SFA: MUFA: PUFA= 18: 49: 33) fats in healthy proportions.
It is one of the stable cooking oils; having a long shelf life.
Wonderfully pleasant, sweet-flavored peanut oil is low in saturated fats, free from cholesterol, contains essential fatty acid ( linoleic acid (omega-6)) making it as one of the healthiest cooking oils.
Being a vegetable oil, it is a good source of plant sterols, especially ß-sitosterol. The FDA has approved the following claim for phytosterols: "Foods containing at least 0.4 gram per serving of plant sterols, eaten twice a day with meals for a daily total intake of at least 0.8 gram, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease." Phyto-sterols competitively inhibit cholesterol absorption in the gut and thereby can reduce cholesterol levels by 10% to 15%.
Peanut oil is high in calories. Its high-calorie value is because of fatty acids. Nonetheless, the oil is especially rich in mono-unsaturated fatty acids (MUFA) like oleic acid (18:1) that helps to lower LDL or "bad cholesterol" and increases HDL or "good cholesterol" in the blood. Research studies suggest that Mediterranean diet that is enriched with monounsaturated fatty acids help to prevent coronary artery disease and strokes by favoring healthy blood lipid profile.
Peanut oil contains resveratrol, a polyphenol antioxidant, which has been found to have protective function against cancers, heart disease, degenerative nerve disease, Alzheimer's disease, and viral/fungal infections.
Studies suggests that resveratrol cut stroke risk by alteration of molecular mechanisms in blood vessels (reducing susceptibility to vascular damage through decreased activity of angiotensin, a systemic hormone causing blood vessel constriction that would elevate blood pressure) and by increasing production of the vasodilator hormone, nitric oxide.
Peanut oil contains valuable amounts of anti-oxidant vitamin E. 100 g fresh oil has 15.69 mg of alpha-tocopherol and 15.91 mg of gamma-tocopherol. Vitamin E is a powerful lipid soluble antioxidant, required for maintaining the integrity of cell membrane of mucus membranes and skin by protecting it from harmful oxygen-free radicals.
In addition to being a vegetable source, peanut oil is also an ideal choice for deep-frying because it can be heated to a higher temperature (smoke point -450 °F). This results in lower oil retention in the fried foods.
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