ABSTRACT
Fats are essential nutrients in the human diet and are normally in cluded in the diet in the form of cooking fat and oils from plant or animal sources. Fats supply energy and aid in nutrient transport. However, obesity worldwide (Bell et al. 2001; Flegal et al. 2002) and chronic health issues associated with a high-fat diet, including cardiovascular disease, cancer, and diabetes, have turned the attention of researchers to the nature of dietary fat and sources of fat in the human diet. Dietary fat and fatty acids are considered important risk factors in carcino genesis and cardiovascular diseases. Common plant sources of fats are oilseed crops, including sesame, peanut, coconut, canola (or rapeseed), soybean, palm, and blends of one or more of these oils commonly termed vegetable oil; these oils are used in cooking and preparation of food. An oil base in cooking foods also serves as a hydrophobic medium to enhance the bioavailability of hydrophobic phytoche micals and antioxidant vitamins. Vegetable oils are produced mainly from oil seeds (e.g., rapeseed and sunflower seed) as well as from the flesh of some fruits (e.g., olives). Vegetable oils are often a rich source of unsaturated fatty acids, although some saturates are also present. Vegetable oils usually contain natural antioxidants, such as vitamin E, which help the oils resist the rancidity that occurs when oxidation takes place. Sometimes a blend of oils is used in a product to take ad vantage of the desirable characteristics of the different types of oils. Some oils are rich in omega-6 fatty acids (e.g., sunflower and corn oils), while others provide omega-3 fatty acids (e.g., rapeseed and soy oils). Other oils are rich in monounsaturated fatty acids (e.g., olive, rapeseed, and groundnut oils).
