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Title: Advanced imaging and 3D measurement of microstructure in food emulsions and foams
Author: Doherty, Sharon Marie
ISNI:       0000 0004 2720 6092
Awarding Body: University of Ulster
Current Institution: Ulster University
Date of Award: 2010
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Standard commercially available food emulsions and foams, mayonnaise and ice cream respectively, have been examined by both ambient temperature transmission electron microscopy (TEM) and cryo-Dualbeam FIB/SEM and analysed by the 'One Stop Stereological' (OSS) method. In addition a series of specially produced mayonnaise samples with differing viscosities were examined and compared with the standard full fat and half fat mayonnaise samples. Furthermore a sub-optimally produced ice cream specimen was compared with the standard ice cream. Specimens were compared for quality of qualitative information in electron micrographs in both TEM and cryo-Dualbeam FIB/SEM following either chemical fixation for TEM of cryo preservation for SEM and FIB milling. Quantitative 3D structural geometrical data was obtained through the use of ass, on the Mercator (ExploraNova) software system. This estimates 1 st the order stereological quantities volume and surface density and star volume. In addition it gives the 2nd order covariance and cross covariance estimators. In mayonnaise oil, water and citrus fibres were measured. In ice cream air, ice and a continuous matrix were measured. The findings concluded that 1) cryo Dualbeam ™ (FIB/SEM)is superior to non-cryo TEM when measurement of structural geometry is planned; 2) stereo logical measurements are sensitive in detecting minimal changes about the structure function arrangements within food foams and emulsions; 3) the use of grazing incidence FIB planing considerably enhances the efficiency of specimen preparation; 4) a series of mayonnaise samples with different viscosities when analysed led to results that appear to be directly related to their differing physical properties; 5) comparison of ice cream, as in 4) above, with samples prepared optimally and sub-optimally detected significant differences in their 3D structure; 6) the use of 1 st and 2nd order stereological techniques are set to increase in use for analysing food emulsions and foams with respect to production control.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available