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Science of Candy
Richard D. LudescherDept. of Food Science
Rutgers University
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Consider These
Kinds of Solid Candy
Chocolate Hard Candy
Gummi BearsHow are their physical properties similar?
How different?Why?
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Molecular Structure of Solid Candy
Chocolate Crystalline Solid: Cocoa butter matrix
Hard Candy Amorphous Solid: Sucrose solution
Gummi Bears Soft Polymeric Solid: Gelatin gel
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Chocolate: Theobroma cocao
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?
Cocoa Liquor
Sugar
Cocoa Butter
(Milk Powder)
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Chocolate Processing
The conching process grinds and mixesthe incompatible ingredients
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Chocolate Matrixis Crystalline Fat
(Cocoa Butter)
Melts in Your Mouth
(Not in Your Hand)
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Cocoa Butter is made
of Triglycerides
Tripalmitin
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Cocoa Butter Crystals
Proposed structures
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Crystal Forms of Cocoa ButterChocolate Tempering
Tempered chocolate
Cocoa butter is a polymorphic fat
It can form six different crystal structures with
different melting points and properties
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Chocolate Fashion ShowChocolate Show New York, November 8, 2005
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When
Chocolate Goes
Bad
Chocolate Bloom
Formation of new
crystals on surface
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Tempered Bloomed
Thermal abuse melts form V crystals
Liquid fat migrates to the surface where it
crystallizes into unappetizing small, polymorphic
crystals of arbitrary form
Chocolate Bloom
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Rock Candy &
Table Sugar:
Crystalline
Sucrose
Hard Candy &
Lollipops:Amorphous
Glassy Sucrose
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Hard Candy Recipe
Sugar: 5 cups
Corn syrup: 1 cup
Water: 1 cup
Flavor: 1-2 teaspoons oil of peppermint, orange,
anise, cinnamon, wintergreen, cloves, orspearmint, etc.
Color: 1-2 drops of food coloring (if desired)
Mix sugars and water, cook to hard crack stage
(300F), remove from heat, add flavor, mix
well, pour into molds and cool. Store in sealed
container.
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Glass Forms Because Crystallization is
Frustrated by High Viscosity of Liquid Sugar
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Properties of
Amorphous Glassy Sucrose
Solid-like Hard, rigid and brittle
Liquid-like Can dissolve colors and flavors Supersatuated liquid
Softens at high temperature: Glass transition (Tg) Hard & brittle below Tg Soft & malleable above Tg
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Rose Window
Notre Dame, Paris
One of the more
attractive applications
of glass technology
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Sugar
Sculpture
American
Culinary
Federation
NationalConvention,
2003
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Triboluminescenceof Sucrose
(nitrogen emission)
Absorption and
Fluorescence ofWintergreen
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Gummi Bears
Hard Jell-O
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Gummi Bear Recipe
WaterCorn syrup
Sucrose
Gelatin
Citric acid
Coconut oilCarnauba wax
Flavors & Colors
Dissolve sugar and gelatin in boiling water, add syrup,
oil and wax, mix well. Add citric acid, juice, and
flavors and colors. Pour into molds. Cool.
Gelatin is added at levels about 6x that used in Jello.
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Gelatin has been
around for millennia,Jell-O for about a
century
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You may be
familiar withother uses for
Jell-O
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Sus scrofaThe source of most
food gelatin
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Jell-O is a Gel: A 3-D Polymer Network
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Gelatin
Triple Helix
The PhysicalCrosslinks in a
Gelatin Gel
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The word "candy" comes from
Arabic qandi, derived from Persianqand, meaning "sugar.
Wikipedia