Popular Science Book "Eat Less Oil, Eat Better Oil" (Wang Xingguo) Article Selection 13

3 The role of fats in cooking

Oil plays a very important role in cooking. No matter what dish you are cooking, oil is basically indispensable. Oil has two main functions: heat transfer and seasoning. On the one hand, oil can be used as a medium to heat food. Its high temperature can cook food in a short time, thus reducing the loss of nutrients. On the other hand, cooking oil can be regarded as the most commonly used seasoning, which can improve the flavor of food, enhance the sensory properties of food, and increase people's appetite. These two functions usually occur at the same time, closely combined and inseparable.

(1) Produce a special aroma in dishes

Dishes cooked with oil will have a fragrance, and this effect is particularly evident in hot dishes. Because oil is an excellent aroma solubilizer and aroma preserver, it can dissolve the lipophilic aroma substances contained in the food well, thus giving the oil a strong aroma. For example, the aroma and spicy taste formed by frying green onions, peppers, and chilies are all dissolved in oil, which can increase the aroma of the dishes. Of course, the oil itself can also decompose free fatty acids and volatile aldehydes, ketones and other substances during the heating and cooking process, further adding a special aroma to the dishes.

(2) Providing dishes with a special texture and taste

By controlling different oil temperatures during the cooking process, the dishes can acquire special textures and tastes. For example, a warm oil pan can coagulate the protein in the food and gelatinize the starch, making the dishes crispy, tender, and soft. A hot oil pan or a high oil pan can quickly evaporate the moisture on the surface of the food and quickly coagulate the surface protein, preventing food from sticking together. This makes the dishes crispy, or crispy on the outside and tender on the inside.

(3) Promote the formation of better color and brightness of dishes

First, under the high temperature of oil, sugars, proteins and other ingredients in food undergo Maillard reaction and change color, thus producing attractive colors. Secondly, many foods are rich in fat-soluble pigments. When they are heated and boiled together with oil, some of the pigments in the food are dissolved and evenly distributed in the oil, making the dishes colorful. Thirdly, oil has a certain viscosity and a lower density than water. It is reflective and can increase the finish of dishes. For example, when blanching vegetables, adding a small amount of cooking oil will wrap the surface of the food, making the color more green and bright.

(4) Thermal insulation

Fat has a low relative density and always floats on the surface of soup and dishes during the cooking and heating process, just like a lid. It can reduce the loss of nutrients, increase and maintain the temperature of dishes, slow down the heat dissipation of dishes, shorten the heating time and save energy.