Fats are important to health, as well as food preparation. Fats help give diners a feeling of satiety and contribute to cellular functions and vitamin absorption in the body, making them critical despite the bad rep they have received from dieters over the years. In food preparation, fats are used for inducing browning, creating emulsions, developing textures, and adding flavor. Fats, or lipids, are a group of molecules in which most types of cooking oil and cooking fat are included.
The Chemistry of Cooking Fat and Oil
Cooking oils and fats are made up of molecules containing chains of fatty acids. Saturated fats are fats that have no double bonds within the fatty acid chains. This causes the chains to be relatively straight and able to stack on top of each other, creating a solid structure, as seen in butter and other cooking fats from animal origins, at room temperature. Unsaturated fats contain double bonds within the fatty acid chains, which bend the molecular structures and allow fluidity or freedom of movement between the chains, as seen in many plant fats, or oils. Though double bonds and fat fluidity are associated with healthier fats, they also make the molecules more susceptible to oxidation and smoking when overheated both undesirable processes in the commercial kitchen and in terms of health.
The lengths of the fatty acid chains affect the properties of the fat as well. Shorter chains are more likely to be liquid at room temperature, while longer chains tend to be solid. Longer chains are also less soluble in water, the effects of which are seen with separation of oil from other ingredients in foods such as salad dressing and in the process of clarifying butter.
Types of cooking oil and cooking fat
The chemistry of cooking oils and cooking fat lend them to different culinary uses and give them their health properties. Liquid fats such as walnut oil and olive oil are ideal for salad dressings, since they add flavor and health benefits, as well as texture. On the other hand, since these oils are relatively unsaturated compared to other types of oil, they have low smoke points and are therefore less ideal for deep-frying. Over-heating oils can lead to carcinogenic properties and unwanted flavors, making oils with low smoke points better left for other culinary uses. The best cooking oil will have a high smoke point, such as refined soybean oil, which has a smoke point of 420 degrees Fahrenheit as opposed to extra virgin olive oil, which has a smoke point of 375 degrees Fahrenheit.
Fats’ melting properties, rich taste, and texture make them important for baking, thickening, and incorporating into food to improve taste and texture. Folding butter into dough, layer after layer, before baking, separates the layers of dough during baking, giving croissants their flaky texture. This effect works because the separation only happens when the butter melts during baking. During the folding process, the butter incorporates into the dough as a solid, making it workable. The butter contributes to the color, outer crispness, soft interior, and richness in croissants. On the other end of the food spectrum, lamb and beef fat can be ground and added to hamburgers and kebabs to make them extra juicy and tender, while adding flavor. Oils could not produce the same results since the liquid would not incorporate into the ground beef adequately.
The examples of uses for cooking fats and different types of cooking oils are endless. Understanding what is the difference between fats and oils, is very important in the commercial kitchen since it gives cooks and chefs the tools to brainstorm new ways to create the best dishes possible. The different properties of cooking fats and oils lend them to certain dishes and culinary uses which can be realized by understanding the basics of the ingredients.