|
Oils are generally grouped into two categories - unrefined and refined. Whether refined or unrefined the first step in oil extraction is removing it from its seed, fruit or nut. All oil extraction process involves heating of oil to high temperatures so that the impurities are destroyed. However, temperatures above 300 degree F destroy the proteins and natural vitamin E in the oil. Lower the temperature at which oil is heated lesser the damage to it and lesser the yield. This makes good oil more expensive. All vegetable oils contain a combination of saturated, monounsaturated, and polyunsaturated fats in varying proportions. In other words, there is no such thing as saturated-fat-free oil or one containing only polyunsaturated or monounsaturated fat. The dietary difference in cooking oils lies in the proportions each contains of the three basic types of fat.
Definition and process of preparing refined oils: Refined oil can be termed as oil that is fully refined, bleached and deodorized. In other words it means that the oil has been chemically treated to neutralize strong tastes and the acid content. The refined oil is not considered edible unless it is processed, filtered, deodorized and bleached.  Deodorization refers to the process used to remove volatile materials from the oil product. Along with removal of compounds which contribute flavor and odour, free fatty acids, monoglycerides, and some color bodies are distilled off. The resulting product is bland in flavor and odour. Bleaching is the process for removing pigments from fats and oils, and is usually carried out by adding about 1% bleaching clay to oil under vacuum at about 107 degrees celsius. High temperature drives moisture from the clay so that it will absorb the pigments. This is why refined oil appears pale with negligible amount of flavour and aroma.
All oils have "smoking points"-once they reach certain temperature during cooking due to high and extensive heat they burn and become altered at the molecular level, releasing free radicals and acting as harmful trans-fat in the body.
Refined oil versus unrefined oil: Refined oil is generally regarded as lower quality than unrefined oils. Refined oils are used at homes as medium cooking oils, high cooking oils and deep-frying oils. Refined oils are better suited to temperatures of 400 to 500 degree F. In contrast, unrefined cooking oils are used mainly for salad dressing, marinades and light cooking. Unrefined oils may be used for low to medium heat cooking as they can only withstand temperatures of 250 to 350ºF Additionally, unrefined oil contains a full range of bioactive components that have health benefits and provide full flavours to the food.
Cold-pressed and unrefined oils are the best quality oils for consumption, as they are the richest in nutrients and haven`t been transformed by processing into bad oils. However, using them appropriately is crucial as these oils can become unsafe if allowed to heat at high temperatures. It is considered that things that impart colour, odour and flavour to oil are the nutrients. Ironically when these very nutrients are removed from oil they are termed as `pure` or `refined`. The only advantage in using refined oil for cooking is that it can stand high temperature without any alteration in the basic formulations. It may be noted that deep frying food robs it of nutrients and loads it with high fat and extra calories.
Fortified refined oil: These days oil producers have stressed the need to increase the nutrient value of refined edible oils. So vegetable oils very often are fortified with vitamin A in order to enhance their nutritional value. This kind of oil is known as fortified refined vegetable oil.
Choice of oil: Choosing cooking oils should not be simply a matter of taste but also health. The right oil used correctly can offer many health benefits. Using even healthy cooking oil incorrectly can transform it into something unhealthful.
So the best bet is to use a variety of oils judiciously. When considering options, one must keep in that lower the content of saturated fat better it is to prevent clogging in arteries. One fact remains a constant. All cooking oils are cent percent fat. The answer seems to lie not only in scrutinizing the fine print on labels at the supermarket and then choosing among the cooking oils that offer health benefits, but in using them sparingly. In order to follow a healthy diet it is important to curb the total amount of fat in the diet. So with cooking oil, remember, less is more.
|
