Lipids a category of organic compounds that are insoluble in water and have a greasy feel Pringles Calories Fat Saturated Fat Cost Regular Pringles 150 9 25 100 Light Pringles ID: 685211
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Slide1
Lipids: Nature’s Flavor EnhancersSlide2
Lipids
…
a category of organic compounds that are insoluble in water and have a greasy feel.Slide3
Pringles
Calories
Fat
Satur-ated
Fat
Cost
Regular Pringles
150
9
2.5
$1.00
Light Pringles
70
0
0
$2.58Slide4
Terms used for lipids:
Fat
Oil
Shortening
Grease
Cholesterol Slide5
Lipids, like carbohydrates, contain
carbon
,
hydrogen, and oxygen
.
But lipids do not provide structure to food products and they cannot dissolve in water.Slide6
Three general types of lipids in foods and the human body…
Triglycerides
Phospholipids
Sterols
Slide7
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.Slide8
Glycerides – 1
st
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.Slide9
Fatty Acids…
are organic molecules that consist
of a carbon chain with a carboxyl
group at one end.Slide10
Phospholipids- 2
nd
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. Slide11
Phospholipids- 2
nd
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.
Slide12
Sterol – 3
rd
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.Slide13
To understand the effects of
lipids in food mixtures,
you need to understand
the ways lipids are categorized
.Slide14
Lipids are grouped according to
:
molecular structure
physical state at room temperature
dietary sourcesSlide15
Molecular Structure (category)
One way to categorize lipids is by
how
saturated their carbon chains are
with hydrogen atoms.Slide16
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.Slide17
Molecular Structure (category)
When fatty acids have the maximum number of hydrogen atoms, they are
saturated
.
Examples
: butter, shortening, coconut oilSlide18
Molecular Structure (category)
Fatty acids that have one double bond in the carbon chain are called
monounsaturated
.
Examples
: olive oil, almonds, walnuts, canola oilSlide19
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 oilSlide20
Physical State (category)
Lipids that are
solid
at room temperature
are called
fats
.Lipids that are
liquid at room temperature are called oils.Slide21
Physical State (category)
Hydrogenation
– adding hydrogen atoms to an unsaturated fat to increase its saturation level.Slide22
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 chocolateSlide23
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 olivesSlide24
Food Source (category)
Linolenic acid
comes from soybeans and wheat germ.
Animal fats
are found in meat and poultry.
Marine oils
come from fish.Slide25
Functions of Lipids in
Food Preparation
Transfer heat
Tenderize
Aerate (add air to a batter)
Enhance flavor
Lubricates
Liquids in emulsionsSlide26
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.Slide27
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.Slide28
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.Slide29
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.Slide30
Functions of Lipids in
Food Preparation
Lubricates
– makes food seem moister and easier to chew.
Examples
: Marbling in meat; mayonnaise spread on sandwichesSlide31
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 dressingsSlide32
Lipids in Your Diet - Functions
Concentrated source of energy
– 9 calories / gram
Cell production
– cell walls made of lipids and proteinsSlide33
Lipids in Your Diet - Functions
Temperature regulation
– fatty tissue insulates and holds body warmth
Helps transport vitamins
– some vitamins needs fat to be transportedSlide34
Essential Fatty Acids
Fatty acids that the body cannot produce
:
Linoleic acid
Linolenic acid
Both of these are polyunsaturated
Both are found in most plants and fish oilsEssential for growth and developmentSlide35
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 lipidsSlide36
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.Slide37
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.Slide38
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.