For frying potato chips and other foods to be served cold, fats which are soft or liquid at room temperature give more luster to the products than fats with higher melting points. (See Table XXVIII on page 138.) Olive oil, butter, and margarine are not suit¬ able for deep-fat frying since they smoke at too low temperatures. It must be recog¬ nized, however, that free fatty acids soon [146] ■develop in fat used for deep-fat frying, thereby lowering the smoking point. There¬ fore, by repeated use of the fat, an initially high smoke point often is brought down to a point that is unsatisfactory for frying. The use of a thermometer is advised to as¬ sure correct deep-fat frying temperatures. Without a thermometer, the time required to brown a one-inch cube of bread in the hot fat can be used as a guide. Table XXXI states the approximate temperatures for deep-fat frying and the approximate time required to brown a cube of bread at the various temperatures. Table XXXI • Temperatures for Deep-Fat Frying Food Product Temperature of Fat Approximate Time to Brown One-Inch Cube of Bread Doughnuts, fish, shellfish, °Fahrenheit Seconds fritters . Coated vegetables and cro- 350 to 365 60 quettes . French-fried potatoes and 375 40 potato chips . 375 to 3851 30 to 40 The choice of a fat for pan-frying or saute¬ ing is not limited to those with a high smok¬ ing point, since cooking by these methods may be carried out at lower temperatures than are successful for deep-fat frying. Meat drippings, all kinds of lard, hydrogenated fats, butter or margarine, and the vegetable oils may be used, but the fact must not be overlooked that these fats are not all alike in the amount of heat they can stand. Flavor, cost, and availability are the main points to be considered. For Shortening. When fat is used for shortening flour mixtures, such as pastry, quick breads, yeast breads, and cakes, its pur¬ pose is to make the product tender and, in some cases, to make it flaky also. These 1Varies with the potato, size of pieces, and method of frying. [147] various products differ in texture and desired flavor and therefore may require somewhat different qualities in a fat. The differences in the shortening value of fats are most important in pastry and in products with a similar texture, such as bis¬ cuits and shortcake. When fat is used for shortening, it makes the product tender by surrounding the gluten and starch particles of the flour and lessening their adhesiveness. The most tender pastry is the one in which the fat surrounds the greatest surface of gluten and starch particles, adheres to them, and is not squeezed out by pressure. There are several factors working together which affect the amount of surface area covered and the extent to which the fat adheres to the flour particles, or, in other words, the short¬ ening power of a fat. These include: (1) the amount of fat in the mixture, (2) its degree of unsaturation, (3) its plasticity or ability to be worked, and (4) the other ingredients used and the method of combining them.

AI-modernized reading of the original text

For frying potato chips and other foods to be served cold, fats which are soft or liquid at room temperature give more luster to the products than fats with higher melting points. (See Table XXVIII on page 138.) Olive oil, butter, and margarine are not suit¬ able for deep-fat frying since they smoke at too low temperatures. It must be recog¬ nized, however, that free fatty acids soon [146] develop in fat used for deep-fat frying, thereby lowering the smoking point. There¬ fore, by repeated use of the fat, an initially high smoke point often is brought down to a point that is unsatisfactory for frying. The use of a thermometer is advised to as¬ sure correct deep-fat frying temperatures. Without a thermometer, the time required to brown a one-inch cube of bread in the hot fat can be used as a guide. Table XXXI states the approximate temperatures for deep-fat frying and the approximate time required to brown a cube of bread at the various temperatures. Table XXXI • Temperatures for Deep-Fat Frying Food Product Temperature of Fat Approximate Time to Brown One-Inch Cube of Bread Doughnuts, fish, shellfish, °Fahrenheit Seconds fritters . Coated vegetables and cro- 350 to 365 quettes . French-fried potatoes and potato chips . 375 to 3851 30 to 40 The choice of a fat for pan-frying or sauteing is not limited to those with a high smok¬ ing point, since cooking by these methods may be carried out at lower temperatures than are successful for deep-fat frying. Meat drippings, all kinds of lard, hydrogenated fats, butter or margarine, and the vegetable oils may be used, but the fact must not be overlooked that these fats are not all alike in the amount of heat they can stand. Flavor, cost, and availability are the main points to be considered. For Shortening. When fat is used for shortening flour mixtures, such as pastry, quick breads, yeast breads, and cakes, its pur¬ pose is to make the product tender and, in some cases, to make it flaky also. These 1Varies with the potato, size of pieces, and method of frying. [147] various products differ in texture and desired flavor and therefore may require somewhat different qualities in a fat. The differences in the shortening value of fats are most important in pastry and in products with a similar texture, such as bis¬ cuits and shortcake. When fat is used for shortening, it makes the product tender by surrounding the gluten and starch particles of the flour and lessening their adhesiveness. The most tender pastry is the one in which the fat surrounds the greatest surface of gluten and starch particles, adheres to them, and is not squeezed out by pressure. There are several factors working together which affect the amount of surface area covered and the extent to which the fat adheres to the flour particles, or, in other words, the short¬ ening power of a fat. These include: (1) the amount of fat in the mixture, (2) its degree of unsaturation, (3) its plasticity or ability to be worked, and (4) the other ingredients used and the method of combining them.

Foods, their selection and preparation