The consistency of commercial mayonnaise, mustard and tomato paste samples
was assessed by squeezing flow before and after compression or stirring, by
hand and with a domestic blender which caused intensive shearing. The spec
imens before and after these treatments were squeezed between Teflon(R) coa
ted parallel plates mounted on an Instron UTM model 5542 to a final height
of 0.8 mm and had been let to relax before the crosshead was withdrawn. The
ir consistency was assessed in terms of their apparent stress at three heig
hts, and after relaxation for I and 2 min at 0.8 mm height. Compression of
the specimen prior to its testing (1-3 times) has very little effect on the
specimen's consistency which supports the view that there was little frict
ion between the Teflon(R) coated plates and the samples. Shearing caused me
asurable loss of consistency in the mustard and tomato paste which was not
fully restored even after three hours. The sheared mayonnaise restored much
of its consistency after about an hour as Judged by the apparent stress at
a given height, and almost fully recovered it if Judged by the apparent re
sidual stress after relaxation.