Transcript Complex Carbohydrates

 Called
polysaccharides
• Composed of many sugar units
 Types
of complex carbohydrates include:
• Starches, cellulose, gums, and pectins
 Starches: complex
carbohydrate consisting of molecules
of sugar units or saccharides linked in branched or
straight chains
 Most abundant in diet
 Polymers of sugar
 Polymer: large molecule that consists of large numbers of small molecular units linked
together
Amylose – linear, chainlike
 Provides gelling characteristic
1.
Amylopectin – branched
 Provides cohesion or thickening
properties when cooked with liquid
2.
*Most foods contain a mixture
 Forms
rigid structure of plants
• Ex: celery strings, corn kernel membranes
 Humans
cannot digest cellulose
• Cellulose in our diet = fiber (provide bulk; feel full)
• Sources: fruits, vegetables, and grains
*although plants contain cellulose, that
doesn’t always mean the plant is high
in fiber
 Gums: soluble
in water and extracted from plants
 Thicken and stabilize mixtures
 Trap color & flavor
 Provide stability and texture for foods
• Salad dressing and gummy candies
 Used
as food additive
• Ex: guar gum, gum Arabic, carob bean gum,
carrageenan, agar, xanthan gum
 Use
the iPads or mobile devices to research the
following gums used as food additives
 Be
sure to include a minimum of TWO traits and THREE
functions of each.
• See example for alginates (must still include 1 additional trait and
2 additional functions)
 Pectins: found
in plant cells and made of chemical
derivatives of sugar called sugar acids
 Naturally occurs in fruit
• Holds cells together (hold skin on fruit)
 Produce
a strong gel
• Jams and jellies
1.
Provide structure
• Flour provides majority of bulk in
baked goods
2.
Bind products together
• Amylose molecules work better to
hold batters to vegetables/meats
for deep frying
3.
Thicken products
 Retrogradation: firming
of a gel during cooling and
standing
• Good – need gel to form during cooling
• Bad- cracks form in gel (ex: gravy)
 Syneresis: water
leaking from a gel
• Ex: liquid separated from mustard
 Viscosity: resistance
of a mixture to flow
• Measures a starch’s thickening ability
• Lower the viscosity readings, higher the viscosity
Opacity vs Translucency
 Opacity: how much an object blocks light
• Gels made with wheat starch
 Translucency: how
much light passes through an object
• Gels made with cornstarch or potato starch
 Starch
1.
granules separated to prevent lumping
Cold water paste – quickly stirring starch while adding
at least an equal amount of cold water
• Thicken soup stock or milk gravy; make gravy from broth
• Cornstarch & Water
2.
Starch and fat – equal amounts, then liquid can be
slowly added
• White sauce and gravy from meat drippings
• Roux
3.
Starch and sugar
• Sugar helps separate starch granules and keep them from sticking
together
• Used in sweet sauces and puddings
 Divided
into 2 categories
• Starch
• Indigestible fiber
 Should
be ½ of your calorie intake daily
• Eat carbs every 4-6 hours
 Carbohydrates
in the form of glucose are the only
source your brain can use
 Provide
bulk for the digestive processes
 Lower cholesterol levels in the blood
 Promotes utilization of fat