Hydrogenated Fats. Hydrogenated fats are marketed under a variety of trade names. They are refined, bleached vegetable oils, normally liquid at room temperature, which have been solidified to a plastic state by the addition of hydrogen. They then are deodor¬ ized. They are whipped or aerated to give additional plasticity and creaming quality, and to make them appear whiter. Hydro¬ genated fats are of smooth texture and of more bland flavor than natural unrefined fats. Vegetable Oils. Vegetable oils or salad oils are available by the name of the source of the oil from which they are made or under trade names with a designation of the source of the oil. Corn oil is expressed from the germ of the corn grain; cottonseed oil from the crushed seeds of the cotton plant; olive oil from ripe olives. The highest quality of "virgin oil” is the first oil expressed under light pressure, and is unrefined. Most olive oil on the retail market is the result of heavy pressure plus further treatment. Olive oil may not be blended with other oils unless so labeled. Peanut oil is expressed from ground peanuts; soya oil, from soybeans. Refined and de¬ odorized soya oil is sold for salad oil. Amounts and Kinds to Buy. In buying table fat, fat for frying and shortening, and oils for salad dressing, the amounts to be purchased at one time depend upon a num¬ ber of factors. These include: (1) the diet¬ ary needs of the family; (2) the use made of fat in food preparation; (3) suitable storage space in relation to the keeping quality of the fat; and (4) the amount of money saved by quantity purchase. The choice of fats from those available on the market depends in large measure upon the uses to which they will be put, personal taste, and food budget. CARE AND STORAGE The properties of fats, like those of other foods, determine how they should be cared for and stored. Fats and foods rich in fat are unstable and deteriorate rapidly unless properly handled. Causes of Deterioration. There are at least four causes of deterioration of pure fats and fat-rich foods. These are discussed below. Absorption of Odors. Any pure fat or food rich in fat, as egg yolks, cream, butter, and fat meat, may absorb odors from other foods stored near them. They also take on such foreign odors as those from spoiled food and from paint. Oxidation. Unsaturated fats and oils readily take up oxygen when exposed to the air. Oxidation is probably the most impor¬ tant factor in the production of rancidity in processed fats. The conditions known to prevent oxidation are these: (1) exclusion of air, (2) exclusion of light, and (3) low tem¬ perature. Enzyme Action. The action of lipase, an enzyme which splits fat, develops an objec¬ tionable odor and a soapy flavor in foods of high fat content stored at too high a tem¬ perature. Low temperatures retard this ac¬ tion. Cooking will stop it altogether, since lipase, like other enzymes, is destroyed by heat. [144] Microorganisms. Bacteria and molds do not grow in pure fat to cause spoilage, but many foods rich in fat, with moisture and other constituents present, spoil from a growth of these microorganisms! Butter, margarine churned in milk, and fat meats are subject to such spoilage. Low storage temperatures retard this type of spoilage. Cooking of those fat-rich foods which can be cooked also delays spoilage.

AI-modernized reading of the original text

Hydrogenated Fats. Hydrogenated fats are marketed under a variety of trade names. They are refined, bleached vegetable oils, normally liquid at room temperature, which have been solidified to a plastic state by the addition of hydrogen. They then are deodor¬ ized. They are whipped or aerated to give additional plasticity and creaming quality, and to make them appear whiter. Hydro¬ genated fats are of smooth texture and of more bland flavor than natural unrefined fats. Vegetable Oils. Vegetable oils or salad oils are available by the name of the source of the oil from which they are made or under trade names with a designation of the source of the oil. Corn oil is expressed from the germ of the corn grain; cottonseed oil from the crushed seeds of the cotton plant; olive oil from ripe olives. The highest quality of "virgin oil” is the first oil expressed under light pressure, and is unrefined. Most olive oil on the retail market is the result of heavy pressure plus further treatment. Olive oil may not be blended with other oils unless so labeled. Peanut oil is expressed from ground peanuts; soya oil, from soybeans. Refined and de¬ odorized soya oil is sold for salad oil. Amounts and Kinds to Buy. In buying table fat, fat for frying and shortening, and oils for salad dressing, the amounts to be purchased at one time depend upon a num¬ ber of factors. These include: (1) the diet¬ ary needs of the family; (2) the use made of fat in food preparation; (3) suitable storage space in relation to the keeping quality of the fat; and (4) the amount of money saved by quantity purchase. The choice of fats from those available on the market depends in large measure upon the uses to which they will be put, personal taste, and food budget. The properties of fats, like those of other foods, determine how they should be cared for and stored. Fats and foods rich in fat are unstable and deteriorate rapidly unless properly handled. Causes of Deterioration. There are at least four causes of deterioration of pure fats and fat-rich foods. These are discussed below. Absorption of Odors. Any pure fat or food rich in fat, as egg yolks, cream, butter, and fat meat, may absorb odors from other foods stored near them. They also take on such foreign odors as those from spoiled food and from paint. Oxidation. Unsaturated fats and oils readily take up oxygen when exposed to the air. Oxidation is probably the most impor¬ tant factor in the production of rancidity in processed fats. The conditions known to prevent oxidation are these: (1) exclusion of air, (2) exclusion of light, and (3) low tem¬ perature. Enzyme Action. The action of lipase, an enzyme which splits fat, develops an objec¬ tionable odor and a soapy flavor in foods of high fat content stored at too high a tem¬ perature. Low temperatures retard this ac¬ tion. Cooking will stop it altogether, since lipase, like other enzymes, is destroyed by heat. [144] Microorganisms. Bacteria and molds do not grow in pure fat to cause spoilage, but many foods rich in fat, with moisture and other constituents present, spoil from a growth of these microorganisms. Butter, margarine churned in milk, and fat meats are subject to such spoilage. Low storage temperatures retard this type of spoilage. Cooking of those fat-rich foods which can be cooked also delays spoilage.

Foods, their selection and preparation