Carbohydrates, sugar
solutions, and candies
Solutions
• Solutions consist of two parts
– Solvent = dissolving substance, i.e.
water
– Solute = substance being dissolved,
i.e. sugar
Solubility
• The extent to which a solute will
dissolve in a given amount of
solvent at a given temperature is
called
ll d its
it solubility
l bilit
1
Solution characteristics
• Solutions are homogeneous
• Solutions do not separate over
time
Solubility depends on
• Temperature
– As temperature increases, the solubility of
solids (but not gasses) in water increases
– Sugar
g ((0oC):
) 179g
g ; Sugar
g ((100oC):
) 487g
g
• Characteristics
– “like dissolves like”
– water dissolves polar things, oil dissolves
non-polar things
Solubility depends on
• Presence of other ingredients
Tea + hot water
Tea beverage
cool
“Scum” is
dissolved
Lemon juice
(acid)
“Scum” formation
insoluble tannin complex
2
Rate of dissolving depends on
• Particle size
– The smaller the particle, the larger
the surface area, the faster it
dissolves
96 sq in,
a 16 fold
increase
6 sq in
Larger surface area
Smaller surface area
Colligative properties
• These are properties which depend
on the number of dissolved
particles, not on what those
particles
ti l are
– Boiling point elevation
• Candy
– Freezing point depression
• Frozen desserts
Boiling point elevation and
freezing point depression
BP2
BP1
BP = 100C
FP = 0C
Solvent
H 2O
FP1
Solution
FP2
More concentrated
solution
Increasing solute concentration
3
Candy and carbohydrates
• Carbohydrates
– Monosaccharides/disaccharides
– Market forms of sugars
– Market forms of syrups
– Properties of sugars
Candy and carbohydrates
• Candy making
– Crystalline candy
– Crystal size
– Solution saturation
• Interfering agents
– Non-crystalline candy
– Maillard browning
Monosaccharides
• Glucose
– Most common sugar in nature
– Also called dextrose
• Fructose
– Sweetest natural sugar
– Main sugar in honey
4
Disaccharides
• Maltose
– Two glucoses
– Found in corn syrup
• Lactose
– Glucose and galactose
– Milk sugar
• Sucrose (table sugar)
– Glucose and fructose
– From sugar cane or sugar beet
Sugars -- Market forms
• Granulated
– Crystalline sucrose
• Brown
– Sucrose with a coating of molasses
• Powdered
– Finely ground granulated with anticaking
agent
• Invert
– Hydrolyzed sucrose
Invert sugar
H2O
Glucose--Fructose
Glucose + Fructose
Acid or
enzyme
Invert sugar
5
Market forms of syrups
• Molasses
– From sucrose processing
Molasses
Sucrose
Molasses
Market forms of syrups
• Corn syrup
Starch
Glucose + Maltose + Dextrins
• High fructose corn syrup (HFCS)
Corn syrup
Glucose + Fructose + Maltose +
Dextrins
Glucose isomerase
6
Market forms of syrups
• HFCS has the advantages over
sucrose that it is sweeter and
cheaper
• Maple syrup
Sap
40 gallon
heat
Syrup
1 gallon
The distinctive flavor of maple syrup is developed
during the boiling down process
Market forms of syrups
• Honey
– High in fructose (the sweetest natural
sugar) 38% fructose, 31% glucose
• Sorghum
– Similar to molasses
• Lightning Quiz
Sugar properties
• Action of water
– Most sugars are water soluble
• Sucrose>>>Lactose
• Fructose>>Glucose,
F
t
>>Gl
G
Galactose
l t
• Most sugars are hygroscopic
– They attract water to themselves
(due to so many OH groups in the
sugar structure)
7
Sugar properties
• Effect of heat
– Sugars melt, then caramelize at
higher temperatures
• Effect of acids or enzymes
– Acids and enzymes (sucrase,
invertase ) will convert sucrose to
invert sugar
– The enzymes of yeast will convert
sucrose to alcohol and carbon dioxide
Candy making
• Aim: To produce small sucrose crystals
• In candy and frozen desserts, crystal
size is texture
• Endpoint cooking temperature is of
extreme importance as this determines
the concentration of sugar in the syrup
• Thermometer must be calibrated
Animation
Candy making
Heating
End
point
temp
Cooling
Unsat.
Saturation
Unsat.
Room temp
Supersaturated
Room temp
8
Candy making
• To form sugar crystals (candy) you
must be in the supersaturated
region
• The question is, where in the
supersaturated region do you
induce crystallization?
Crystallization
Induce here
Induce
here
Room temp
Room temp
Crystallization
• Remember that the aim in making
crystalline candy is to make small
crystals
• Thus, we want to induce
crystallization just a little above
room temperature to maintain
small crystal size and smooth
texture
9
Controlling candy crystal size
• Cook to correct endpoint
temperature
– Calibrate thermometer!
• Make sure all sucrose is in solution
x
Controlling candy crystal size
• Cool to correct degree of
supersaturation
• Add interfering agents
– Fats
Fats, oils butter,
butter chocolate (protein and fat),
fat)
milk (protein and fat), gelatin
(marshmallows), food gums, eggs, (protein
and fat), syrups (corn syrup, HFCS, invert
sugar)
– All these things are non-crystalline and
interfere with the growth of sugar crystals
Crystalline candies
• Fudge
• Fondant
• Divinity
10
Non-crystalline candies
• Rock candy
– High temperature
• Lollipops
– High temperature
• Butterscotch
– High temperature
Non-crystalline candies
• Peanut brittle
– High temperature
• But, peanut brittle has an
ingredient that no other candy has
An odd ingredient?
• 1 pint Karo, Blue Label
1 cup granulated sugar
1/4 teaspoon vanilla
1/3 tteaspoon b
baking
ki
soda
d
2 cups roasted peanuts
11
Baking soda in peanut brittleWhat does it do?
• Neutralizes acids produced
by thermal degradation of
sugar; this improves the
taste of the candy
• When it neutralizes the
acids, carbon dioxide is
trapped in the candy
matrix; this improves the
texture
• Baking soda changes the
pH of the candy and this
causes changes in the
browning pigments; this
improves the color
Non-crystalline candies
• Caramels
– Are caramel colored due to Maillard
browning
– This is a reaction between p
protein and sugar
g
at high temperature that produces
pigments, aromas, and flavors
– Caramels are non-crystalline because of the
large amount of interfering agents used in
the recipe
Non-crystalline candies
• Taffy
– Uses both high temperature and lots
of interfering agents to remain noncrystalline
12
Chocolate covered cherries
time
Acids and/or enzymes
called
ll d sucrase or invertase
i
t
Fondant, a solid
Lightning Quiz
Liquidy coating?
How did this
happen?
13