Colloidal and surface phenomenal aspects of Ice cream

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Colloidal and surface phenomenal aspects of Ice
cream
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History

• Little is known
• Introduced from Europe
• Records indicate served by Governor Bladen of
  Maryland in 1700
• In 1832 a recipe and manufacturing methods were
  invented
• First large scale ice cream plant established in
  1851 in Baltimore

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Design considerations

• Flavor
• Texture
• Body
• Melt characteristics
• Color
• Inclusion of candies and fruit

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Ingredients contributing to properties

• Fat and water
• Emulsifiers
• Stabilizers
• Proteins
• Sweeteners
• Other elements

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Fat and water

• Fat
• Large molecule
• Triacylglyceride
• Nonpolar
• Vanderwaals

• Water
• Small molecule
• Hydrogen dioxide
• Polar

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Emulsion

• Mechanically dispersed
• Low internal phase ratio
• Low solubility (14w/w)
• Droplets .1-10micro meter
• Fat network
• Large surface to volume ratio
• Milk fat has wide melting pt around 40 C
• This partial crystallinity adds to ability to
  network

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Additional properties of fat

• Produces characteristic smooth texture
• Adds richness and sweetness in flavor
• Aids in dissolving some flavors and vitamins

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Emulsifiers

• Emulsion stabilizers
• Decrease interfacial tension from 15-25 to less
  than 10dynes/cm
• Before freezing- decrease ability of fat to
  coalesce
• During freezing-cause partial destabilization of
  lipid phase
• During whipping- cause partial coalescence
• When emulsifier conc. Increases fat penetrates
  air phase more
• Results in stable air phase, stable fat network,
  smoothness in texture

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Resulting benefits

• Decreased freezing time
• Increase minuteness of components
• Increase stiffness
• Increase uniformity of melting

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Types

• OriginalLecithin
• Found in egg yolks and soybeans
• Phospholipids
• Are modified for polarity and hydrophobicity

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Types

• Poly sorbate
• Sorbitan ester
• Smaller in MW
• Produces low tension
• Very thin membrane
• Maximum fat destabilization
• Also drying agent-adsorbs some water

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Types

• Mono and Di glycerides
• Derived from partial hydrolysis of fats and oils

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Stabilizers

• Effect ice/ water mixture
• Polysacharides large hydration capability
• Increace viscocity decreacing diffusional
  abilities
• Stabilize foam phase
• Do not actively effect interfacial tension but
  decreace the avaliability of water indirectly
  effecting tension
• Stabilize emulsion
• Increace smoothness

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Stabilizers cont.

• Decrease size of ice crystals
• Decrease diffusion and the total growth
• Depresses freezing point as water is removed from
  solution maintaining water phase
• Decreases heat shock through this mechanism
• Increase stiffness of product
• Decrease moisture migration out of product

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Types

• Carboxymethyl cellulose (CMC)
• Locust Bean Gum
• Carrageenan
• Guar gum
• Geltatin

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Proteins

• Large polymers
• Both hydrophobic and hydrophilic
• Extend on interface
• Create micelles
• Both stabilizers and emulsifiers increase protein
  concentration
• Increase viscosity
• Critical protein depletion before partial
  coalescence
• Increased hydrophobicity at interface yielding
  stability
• Decrease melting rates
• Increased shape retention

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Types

• Caseins
• 80 total milk protein
• Phosphoproteins precipitated at 4.6 ph
• Micelles
• Preferentially diffuse out of lipid phase
• Whey
• Soluble at low ph
• Globular

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Sweeteners

• Taste
• Improve texture and palatability
• Also depresses freezing point

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Other ingredients and factors

• Ions
• effect destabilization, wetness
• influence electric double layer and repulsion
• citrate and phosphate increase protein
  aggregation and decrease coalescence
• Ca and mg decrease aggregation and promote
  coalescence
• Additives (nuts,candy etc.) add crystal centers,
  also may effect moisture content
• Phase volume
• Temperature (freezing, mixing, packaging)