Lipids: Nature’s Flavor Enhancers

Lipids…

a category of organic compounds that are insoluble in water and have a greasy feel.

PringlesCalories Fat Satur-

ated FatCost

Regular Pringles

150 9 2.5 $1.00

Light Pringles

70 0 0 $2.58

Terms used for lipids: Fat

Oil

Shortening

Grease

Cholesterol

Lipids, like carbohydrates, contain carbon, hydrogen, and oxygen.

But lipids do not provide structure to food products and they cannot dissolve in water.

Three general types of lipids in foods and the human body…

Triglycerides

Phospholipids

Sterols

Most lipid molecules found in foods and the body have two basic parts.

The base or core is a glycerol molecule called glycerides.

The second part of most molecules is called a fatty acid.

Glycerides – 1st type of lipid Monoglycerides – is a glycerol with one

fatty acid attached at the site of a hydroxyl group.

Diglycerides – is a glycerol with two fatty acids attached.

Triglycerides – have a fatty acid joined at each of the three hydroxyl sites.

Fatty Acids…

are organic molecules that consistof a carbon chain with a carboxylgroup at one end.

Phospholipids- 2nd type of lipid A second basic type of lipid that has a glycerol

base with two fatty acids AND a phosphorus-containing acid attached.

The fatty acids are soluble in water.

This allows phospholipids to mix with both water-based and fat-based substances.

Phospholipids- 2nd type of lipid Phospholipids help carry fats back and

forth across cell membranes into the water-based fluids.

In food products, phospholipids keep foods like mayonnaise from separating.

Sterol – 3rd type of lipid Complicated molecules derived or made

from lipids. Examples: cholesterol, vitamin D, steroid

hormones. Cholesterol is a part of every cell in the

human body.

To understand the effects of

lipids in food mixtures,

you need to understand

the ways lipids are categorized.

Lipids are grouped according to:

molecular structure

physical state at room temperature

dietary sources

Molecular Structure (category)

One way to categorize lipids is by howsaturated their carbon chains arewith hydrogen atoms.

Molecular Structure (category) Each carbon atom is capable of

forming 4 bonds. A carbon atom can bond twice to

another carbon atom. This is called a double bond.

Fatty acids will have 0, 1, or multiple double bonds.

Molecular Structure (category)

When fatty acids have the maximum number of hydrogen atoms, they are saturated.

Examples: butter, shortening, coconut oil

Molecular Structure (category) Fatty acids that have one double

bond in the carbon chain are called monounsaturated.

Examples: olive oil, almonds, walnuts, canola oil

Molecular Structure (category) Polyunsaturated fatty acids have

two or more double bonds in the carbon chain. Each double bond bends the fatty acid chain. Bends make it difficult for the molecules to pack together tightly.

Examples: safflower, sunflower, and

corn oil

Physical State (category)

Lipids that are solid at room temperature are called fats.

Lipids that are liquid at room temperature are called oils.

Physical State (category)

Hydrogenation – adding hydrogen atoms to an unsaturated fat to increase its saturation level.

Physical State (category) Advantages of hydrogenated vegetable oil:

Longer shelf life than oil Greater stability than lard Costs less than lard Faster dissolving and setting properties in

chocolate

Food Source (category) Milk fats come from the milk

of cows or goats. Lauric acids come from palms

of coconut. Vegetable butters come from seeds

of tropical plants. Oleic-linoleic acids come from corn,

peanuts, sunflowers, or olives

Food Source (category)Linolenic acid comes from

soybeans and wheat germ.Animal fats are found in meat

and poultry.Marine oils come from fish.

Functions of Lipids in Food Preparation

Transfer heat Tenderize Aerate (add air to a batter) Enhance flavor Lubricates Liquids in emulsions

Functions of Lipids in Food Preparation

Transfer heat – lipids will continue to increase as heat is added; every lipid has a smoke point and a flash point.Smoke point – temperature at which the

fatty acids begin to break apart and produce smoke.

Flash point – temperature at which lipids flame.

Functions of Lipids in Food Preparation

Tenderize – fats tend to shorten the long protein strands of flour of most baked goods, thereby, tenderizing the baked good.

Functions of Lipids in Food Preparation

Aerate (add air to a batter) – saturated fat has the ability to allow tiny air pockets to form when batters are beaten sufficiently. If over-beaten, fat could melt and then air pockets are lost.

Functions of Lipids in Food Preparation

Enhance flavor – fats add flavor, helps transfer and intensify flavor. Examples: Butter adds flavor to bread; onions and garlic cooked in fat will be stronger than if cooked in a broth base.

Functions of Lipids in Food Preparation

Lubricates – makes food seem moister and easier to chew.

Examples: Marbling in meat; mayonnaise spread on sandwiches

Functions of Lipids in Food Preparation

Liquids in emulsions – usually one of two liquids in an emulsion – a mixture that contains a lipid and a water-based liquid.

Examples: mayonnaise; bottle salad dressings

Lipids in Your Diet - Functions

Concentrated source of energy – 9

calories / gram

Cell production – cell walls made of

lipids and proteins

Lipids in Your Diet - Functions

Temperature regulation – fatty tissue

insulates and holds body warmth

Helps transport vitamins – some

vitamins needs fat to be transported

Essential Fatty Acids Fatty acids that the body cannot produce:

Linoleic acidLinolenic acid

Both of these are polyunsaturated Both are found in most plants and fish oils Essential for growth and development

Role of Cholesterol Used to build cell membranes – it is a rigid

molecule that helps solidify cell walls; adds stability to cell’s structure

Body makes cholesterol from lipids

Atherosclerosis Results when there is too much

cholesterol in the blood Too much blood cholesterol causes

deposits called plaque. The rigidity of the cholesterol plaque

deposits on the walls of arteries hardens the arteries. This hardening is called atherosclerosis.

Lipoproteins These are clusters of lipid and protein

molecules. Transports cholesterol throughout the body LDL (Low-density lipoproteins) carry

cholesterol from the liver HDL (High-density lipoproteins) find

unneeded cholesterol and return it to the liver. LDL and HDL work together to keep

cholesterol in balance.

Lipoproteins Too much LDL can clog arteries, increasing

risk of heart attack or stroke. High levels of HDL seem to help protect

against heart attack and stroke. Important recommendation – eat a

reasonable amount of the right kinds of lipids.