Understanding Food Chapter 10: Fats and Oils
Dec 16, 2015
Understanding Food
Chapter 10:
Fats and Oils
Functions of Fats in Food
Functions of Fats in Food-Heat transfer
How is food heated in deep-fat frying?
In deep-fat frying, food is quickly cooked in several stages involving: Moisture transfer Fat transfer Crust formation Interior cooking
Functions of Fats in Food-emulsions
There are three parts to an emulsion: The dispersed or discontinuous phase, usually oil. The dispersion or continuous phase, most likely water-based. An emulsifier, which is a stabilizing compound that helps
keep one phase dispersed in the other.
Functions of Fats in Food
Fat’s melting point is determined by the following four characteristics of the fatty acid: Degree of saturation Length Cis-trans configuration Crystalline structure
Functions of Fats in Food
Plasticity The plasticity of fat is its ability to hold its
shape but still be molded or shaped under light pressure.
Flavor The flavor developed in certain foods by
fats is very difficult to duplicate.Texture
Fats also contribute texture.
Functions of Fats in Food
AppearanceFoods are made more appealing by
pigments located in a food’s natural fats.Satiety or Feeling Full
Fats induce a sense of fullness, or satiety.
Types of Fats
The different types of fats: Butter Margarine Shortenings Oils Lard Cocoa butter Fat replacers
Types of Fats
Butter can be purchased in a number of forms. Choices are influenced by: Taste Texture
Standard stick margarine must contain at least 80% fat, about 16% water, and 4% milk solids.
Types of Fats
Shortenings are plant oils that have been hydrogenated to make them more solid and pliable.
Many different types of oils are available for food preparation purposes, and the type of oil used depends on the desired outcome.
Types of Fats
Many refined oils are without any distinguishing characteristics.
Unrefined, cold-pressed oils, such as peanut and olive oils, have the full flavor of the plants from which they were pressed.
Winterizing: A commercial process that removes the fatty acids having a tendency to crystallize and make vegetable oils appear cloudy.
Hydrogenation: A commercial process in which hydrogen atoms are added to the double bonds in monounsaturated or polyunsaturated fatty acids to make them more saturated.
Types of Fats
These animal sources of fat are primarily saturated fat: Lard, which is the fat from swine. Tallow is also an animal fat, but it
is derived from beef cattle or sheep.
Suet is the solid fat found around the kidneys and loin of beef and sheep.
Food Preparation with Fats
Lower-Fat Preparation Techniques
Meal patterns that are lower in fat. Especially lower in saturated fat.
Rely on lower-fat or nonfat cooking methods.
Reduce the fat in recipes.
Food Preparation with FatsOther ways to reduce the amount or modify the type of fat in the diet include:
Fruit preserves and honey Mustard, ketchup, or low-fat salad dressing or
mayonnaise Purées of fruits such as plums, dates, apples, and
figs Crumb crusts Double-crust pies can be converted to one-crust
pies. A nonfat condiment such as salsa, relish, or chutney
Storage of Fats
Storage of fat depends on its type.
Fats such as butter and margarine are best stored in the refrigerator.
Shortenings and most oils are usually stored at room temperature and should be kept tightly covered in a dark spot on the cupboard shelf. They will keep longer if refrigerated.
Olive oil has a shorter shelf life than most vegetable oils and should be refrigerated fairly soon after opening.
Storage of Fats
Rancidity: the chemical deterioration of fats, which occurs when the triglyceride molecule and/or the fatty acids attached to the glycerol molecule are broken down into smaller units that yield off-flavors and odors.
There are two basic types of rancidity: Hydrolytic rancidity Oxidative rancidity