ISSN:
1750-3841
Quelle:
Blackwell Publishing Journal Backfiles 1879-2005
Thema:
Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
,
Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
Notizen:
Fat coagulation begins when ice cream mix is frozen and whipped. The effect is hindered by the simultaneous conversion of water to ice. When frozen ice cream thaws, the ice crystals disappear so that coagulation is able to continue. It leaves a melt with a weak structure which differs from the fat network present in the original mix. This is snbstantiated by the eomparative creep behavior of mix and melt at low rates of shear. The creep behavior of melted ice cream is represented by a mechanical model containing 4 elements: instantaneous elastic compliance, J0; a retarded elastic compliance, J1, comprising an elastic modulus, E1 and a viscosity, π1; and a Newtonian compliance, t/πN, where t is time and πN is the Newtonian viscosity. Ice cream mix requires 6 elements since an additional elastic modulus, E2, and a second viscosity, π2, are associated with retarded elasticity. These additional elements are attributed to globules of 0.5 μ or less, which are separated by only a few Angstroms after flocculation rather than the 50 Å or more separating larger globules. Structure recovery in mix after it has been subjected to high shear indicates pronounced flocculation in the static emulsion. Weak forces of attraction hold the globules together within the flocculate.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1111/j.1365-2621.1966.tb01927.x
Permalink