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Vegetable oils are oils or fat extracted from a variety of plants, fruits, nuts and seeds. Vegetable oils are primarily used for human consumprion but are also used in animal feed, for medinical purposes and in technical applications. The preparation of raw materials includes husking, cleaning, crushing and conditioning. The process of oil extraction is mechanical and involves certain steps. This includes boiling for fruits, and pressing for seeds and nuts.  Oils may be extracted from plants by dissolving parts of plants in water or some other solvent, boiling and then distilling the oil. The oil thus obtained is called essential oil. The oil is then filtered and the residues obtained are conditioned and used for animal feed. Extraction and processing of oil from plants is done in oil factories. Vegetable oils can be classified by source and by use. Oils from plants are used un cooking, for fuel, for cosmetics and for medical purposes.
Types of vegetable oils: Vegetable oils are of three types. The first category of vegetable oil or fat includes cooking oil such as canola oil. The second category called essential oils includes oils that are based on aromatic compounds, are used in flavours, fragrances, for health purposes such as oil of peppermint. The third category is called macerated oils and are those to which other matter has been added, such as herbs.
Essential oil: Essential oil is a concentrated liquid containing volatile aromatic compounds extracted from plants. Essential oils are used in perfumes, aromatheraphy, cosmetics, incense and for flavouring food and drinks. These oils are also known as volatile oil and ethereal oil and are more indicative of the of the fragrant essenceof the plant from which they are extracted.  The commonmost essential oils are lavender, peppermint and eucalyptus. The raw plant material in this case consists of flowers, leaves, wood, bark, roots and seeds all put into a distillation plant as the water is heated, the steam passespasses through the plant materail, vapourizing the volatile compounds. The vapours are then condensed back to liquid.
Macerated oils: Macerated oils are used by herbalists and aromatherapists. Base oils commonly used for maceration include almond oil, sunflower oil and olive oil. These oils are often blended with other herbs and herbal oils to produce the desire effect. Some of the known macerated oils are arnica, chaamomile, calendula, myrrh, marigold, rose, cinnamom.
Edible oils: Edible oils are obtained from plants. Some best known examples are: sunflower oil used for cooking and to make biodiesel; coconut oil used in cooking baking and cosmetics; corn oil used for cooking, has little oodour or taste; peanut oil used for cooking and salad dressing; sesame oil is a light cooking oil; olive oil used for cooking, salads, cosmetics and soaps.
Nut oil: Nut oils are a form of edible oils and used mainly for cooking becaise of their flavour. They are very expensive because of the difficulty in extracting the oil. Some of the commomnly used nut oils are: hazelnut oil, almond oil also used for cosmectics and in medicines; cashew oil; macadamia oil, contains no trans fat and has a good balance of omega 3 and omea 6 oil. Some other edible oils that have plants as their base are apricot oil and has the same use as almond oil.
Drying oils: Vegetable oils that dry to a hard finish at normal temperatures are called drying oils. Such oils are used a the basis of oil paints and wood finishing applications. Vegetable oils in this category are linseed oil, poppyseed oil and tung oil. In assition to these oils, walnut, sunflower and safflower oils are also considerd to be drying oils.
Vegetable oils as biofuel: Vegetable oils also have the property of being used as biofuel. Some of the edibile oils in this category include coconut oil, corn oil, cottonseed oil, flax oil, bran oil, soyabean oil and sunflower oil. Avacado oil is used as a substitute for olive oil and is also used in cosmetics; coriander seed oil used as a flavouring agent in food and pharmaceuticals industries; grape seed oil used as a salad oil and in cosmetics; meadowfoam seed oil is highly stable and used for industrial applications; mustard oil used for cooking and massage; pine seed oil used in salads and as a condiment; thistle oil used for preparing skin care products; wheat germ oil used as a food supplement and in medicines; perilla seed oil is high in omega 3 fatty acids, used as an edible oil, in skin care products.
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