Transcript FST Ch 5 Carbohydrates

CARBOHYDRATES
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Organic chemistry has given the name
saccharide to all carbohydrates
classified as sugars.
Sugar was the common name used before
organic chemists developed the system
used today
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Sugars are organic compounds. That
means they contain carbon compounds
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All living things are composed of carbonbased (organic) compounds
Carbohydrates
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Are …
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one of the six essential nutrients
The body’s main source of energy
The sugars
The starches
The fibers in your diet
 Except for the natural sugar in
milk, nearly all carbohydrates
come from plant sources
Carbohyddrates…
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…are made of three chemical elements
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Carbon
Hydrogen
Oxygen
These are bonded together to form
saccharides – sugar units
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How the elements are arranged, determines
the type of sugar it is…
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Monosaccharide
Disaccharide
Polysacchride
Monosaccharides
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Sugar in their simplest form
Carbohydrate molecules that are
building blocks for more complex
carbohydrates
Monosaccharides in Food
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Glucose – the most prevalent
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also called dextrose, grape sugar & corn
sugar
Found in fruits, vegetables, honey,
corn syrup, and molasses
FRUCTOSE
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The sweetest of all the sugars
Found in honey, molasses,
fruits & veggies
Galactose
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Is produced when lactose(milk
sugar) is digested
Or when milk products are
fermented (cheese& yogurt)
SUGAR
How Sweet It Is
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What is it?
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The white stuff we know as sugar is
sucrose.
It’s two simpler sugar stuck together
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frutcose & glucose
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Also called a….
DISACCHARIDES
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Contain 2 monosaccharides joined together
Sucrose (table sugar) is the most common
Glucose + fructose = sucrose
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Maltose – formed during the digestion of
starch
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Also found in malted grains – the least sweet
Lactose – sugar found in milk
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The body splits disaccharides into
monosaccharides during digestion
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Called hydrolysis
Lactase (enzyme)
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Glucose & galactose
 Galactose broken down to
Glucose (in the liver)
Glucose is used for energy
Polysaccharides
(Polymers)
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Poly = many
Mer = parts Polymer = many parts
They are long chains of molecules (it gets
complicated!)
Polysaccharide Examples
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Starch: is the storage form of energy in
plants. Made of many glucose molecules
bonded together.
Breads, cereals,
Corn, potatoes, & legumes (dried beans)
Polysaccharide Examples
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Fiber: Make up the tough fibrous walls of
plants.
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Not digested by humans
Cellulose, gums, pectins
Found in: Grain products – bread, cereal,
corn, potatoes, & legumes
COMPLEX Carbohydrates
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Man-Made Polymers
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Plastic, nylon, grease
Natural Polymers
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Cotton, wool, hair, skin
Protein, Gelatin
Polysaccharides
Sugar
and its many disguises
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Honey, syrup, corn sugar, corn syrup,
molasses, maple syrup, invert sugar, brown
sugar, sucrose, fructose, glucose, dextrose,
maltose, & lactose
Anything that ends in “ose”
Sugars 6 Functions in Food Prep
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Sweeteners
Preservatives
Tenderizers
Crystallizing Agent
Carmelizing Agent
Fermenting Agent
Sweetners
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Ability to sweeten is its major function in
most foods.
Scientists have found the sweeter the sugar
is, the simpler the structure of the
molecule is.
The longer the sugar chain is, the less
sweet the sugar will seem to be.
Preservatives
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Sugar helps prevent food spoilage
Water is drawn to sugar molecules before it is
drawn to bacteria.
Most single-celled contaminants will dehydrate
and die in concentrated sugar solutions
Helps products such as cakes stay moist
Tenderizers
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Sugar interferes with the flour’s ability to
form an elastic structure (Gluten)
Compare the tenderness of
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An Italian hard roll
A piece of white bread
A sweet roll or donut
Tenderizers
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The tenderizing effect of sugar changes the
viscosity or “pourability” of a batter
Crystallizing Agent
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Sugars ability to dissolve in water increases
as the solution gets hotter.
When water evaporates it increases the
sugar concentration
Sugar crystals that form on the side of the
pan will trigger more crystallization. Put a
lid on it.
Steam will wash the crystals from the sides
Interfering Agents
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A substance that can prevent or slow
crystal growth.
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Corn syrup
Butter
Cream
Caramelizing Agents
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When exposed to high heat – over a period
of time it changes to brown liquid –
caramel.
It is partially responsible for the brown
crust on baked goods and toast.
And the distinctive taste and color of
caramel candy
SUGAR
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Solid at room temperature
Liquifies when heated – changes from clear to
yellow to brown/black –
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Called carmelization
A chemical process
Can be used in many ways
Fermenting Agent
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Plays a major role in the fermentation of
wine, beer and yeast breads.
Sugar is the food supply for the
microorganisms involved in the process.
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Promotes carbon dioxide production in
yeast
Acts a a dehydrating agent in pectin gel
formation (jam & jellies)
Lowers freezing point of mixtures (ice
cream)
Increases boiling point of mixture (candy)
Part 1
The End
Part 2
Simple Sugars
And your
Health
Refined Sugars
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Sugars can be divided into 2 groups
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Sugar that occurs naturally in foods
* milk & fruit
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Sugars added to foods during
processing or at the table.
 Called REFINED SUGARS
Refined Sugars
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Are…
Sweeteners separated from their natural
sources for use as food additives.
Comes from sugar cane, sugar beets & corn
Used as sweeteners, to increase bulk or aid
browning
Refined Sugars
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Sources…
Soft drinks, candy, cake, cookies, donuts
Also… many processed foods such as
catsup, cereal, potato chips and…
Reduced fat or fat free products
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Added sugar increases the calories in food
without increasing the nutrients. (“empty
calories”)
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In other words…
Sugar
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Eat too much – have problems
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Obesity
Diabetes,
Bad teeth
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Experts recommend keeping sugar intake
to no more than 25% of your total calories.
For example: 2000 calorie diet = 500
calories from sugar.
Health Related Questions
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Is Sugar Bad for your teeth?
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Yes! Too much sugar = tooth decay (dental
caries)
Bacteria feed on the carbohydrate particles & form
plaque that clings to teeth.
 As bacteria grow they form acid that eats away
tooth enamel, forming pits which can deepen into
cavities.
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Sticky foods like cookies, crackers,
caramels etc. cling to teeth.
They are more harmful than foods that are
quickly swallowed.
Carbohydrates eaten at meals are less
damaging than between meal snacks
because they are removed by beverages
and other foods eaten with them.
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Do not allow a baby to sleep with a bottle
in their mouth.
The acids formed can destroy their teeth
After feeding, clean gums and teeth with a
soft, clean cloth
Does sugar cause hyperactivity?
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Researchers have found no proof…
However…
Children who eat large amounts of sweets
may be missing important nutrients.
Eating a more nutritious diet can improve
performance.
Is sugar addictive?
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People are born with a preference for
sweet- tasting foods.
Researchers think that the need for sugar is
psychological. We eat sweets because we
like them – not because we are addicted to
them.
Does Too Much Sugar Cause
Diabetes?
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Diabetes mellitus – and inability to use the
hormone insulin.
Insulin regulates blood glucose level by
pulling glucose from the bloodstream.
When the body does not make enough or
does not use it correctly, glucose builds up
in the bloodstream.
Two Types of Diabetes
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Type I – insulin-dependent
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Pancreas does not make insulin
Occurs mostly in children & young adults
Must take injections to regulate
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Type II or noninsulin –dependent
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Body does not respond well to the insulin that
the pancreas makes
Usually occurs in adults over 40
People who are overweight
People whose diets are high in refined sugar
and low in fiber
Can often be controlled with diet and physical
activity
Hypoglycemia (low blood sugar)
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Body produces too much insulin and
causes blood sugar to drop sharply 2-4
hours after eating
Avoid eating large amounts of sugar at one
time.
Eat at regular intervals
Lactose Intolerance
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The inability to digest lactose – the
carbohydrate enzyme in milk.
Symptoms: gas, cramping, nausea &
diarrhea
Occurs most often among nonwhite
populations
Develops as people age
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May be able to eat milk products such as
yogurt, cheese & buttermilk since the
lactose is broken down during the culturing
process.
Will have to get calcium from other
sources.
So…
Exactly what
carbohydrates should
I eat?
Complex Carbohydrates
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Dividing carbohydrates into simple &
complex makes sense on a chemical level
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But doesn’t explain what happens to
different carbs inside the body.
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Starch in white bread & French fries
qualifies as “Complex” – yet the body
converts this starch to blood sugar almost
as fast as it processes pure glucose
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Fructose is a simple carb, but has minimal
effect on the blood sugar
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Other factors that influence how quickly
the carbohydrates raise blood sugar include
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How much it has been processed
Fiber content
Ripeness – more ripe=more sugar
Fat & acid content.
Physical form – finely ground vs. coarsely
ground
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For optimal health get your grains intact
from
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Whole wheat bread
Brown rice
Whole grain pasta
Old-fashioned rolled oats
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Beans (pinto, black, kidney, garbanzo etc)
Fresh fruit
Fresh vegetables
Take good care of yourself
You are the only “You” that you’ve got!!