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 consist

of a carbon chain with a carboxyl

group 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 how

saturated their carbon chains are

with 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.