colloidal and surface phenomenal aspects of ice cream n.
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Colloidal and surface phenomenal aspects of Ice cream
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  1. Colloidal and surface phenomenal aspects of Ice cream

  2. 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

  3. Design considerations • Flavor • Texture • Body • Melt characteristics • Color • Inclusion of candies and fruit

  4. Ingredients contributing to properties • Fat and water • Emulsifiers • Stabilizers • Proteins • Sweeteners • Other elements

  5. Fat Large molecule Triacylglyceride Nonpolar Vanderwaals Water Small molecule Hydrogen dioxide Polar Fat and water

  6. 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

  7. Additional properties of fat • Produces characteristic smooth texture • Adds richness and sweetness in flavor • Aids in dissolving some flavors and vitamins

  8. 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

  9. Resulting benefits • Decreased freezing time • Increase minuteness of components • Increase stiffness • Increase uniformity of melting

  10. Types • Original:Lecithin • Found in egg yolks and soybeans • Phospholipids • Are modified for polarity and hydrophobicity

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

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

  13. 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

  14. 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

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

  16. 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

  17. 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

  18. Sweeteners • Taste • Improve texture and palatability • Also depresses freezing point

  19. 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)