Science of Candy

8/14/2019 Science of Candy

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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

Science of Candy

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