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QUANTIFYING SHEAR EFFECTS ON A MODEL EMULSION SYSTEM
Author(s) -
YURGEC M.J.,
OSBORNE J.,
STEFFE J.F.,
DAUBERT C.R.
Publication year - 2012
Publication title -
journal of food process engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 45
eISSN - 1745-4530
pISSN - 0145-8876
DOI - 10.1111/j.1745-4530.2011.00640.x
Subject(s) - shear (geology) , shear rate , emulsion , homogenization (climate) , rheology , work intensity , materials science , particle size , mechanics , work (physics) , chemistry , composite material , mechanical engineering , chemical engineering , engineering , physics , biodiversity , ecology , biology
A model corn oil‐in‐water emulsion, stabilized by Tween 20 (0.2–0.6%), was subjected to homogenization conditions of time, number of homogenization cycles and pressure (100–800 bar), which corresponded to predetermined shear work and shear power intensity values. This project investigated the roles that shear work and intensity have on the development and destabilization of a sensitive emulsion system. Samples with the same shear work level produced an emulsion with any identical median particle size (MPS). Particle size data were modeled (MPS is a function of shear work and surfactant concentration). The data revealed a critical shear limit, where an increase in shear work no longer reduced the particle size that was directly related to surfactant concentration. A statistical model was adapted to determine the critical shear work value, resulting in the lowest MPS for each surfactant concentration tested. PRACTICAL APPLICATIONS Shear work and shear power intensity are rheological tools that can be used to design processing systems to yield optimum product quality. A process technologist can understand the shear limitations of a fluid system simply by understanding the affects that increasing levels of shear work and shear power intensity have on that system. By understanding the shear input that is occurring within a fluid system caused by various unit operations, a process technologist would be able to correlate this to the known shear limitations and make a determination if the process is too severe or not intense enough. Knowledge of this information would enable a process technologist to better select equipment, piping schematics and settings on devices that cause shear, which could lead to more optimum product quality and less product loss caused by over‐ or under‐shearing.