406 Chapter 23
MacFarlane 1987 ). Zhang et al. (2005)
reported that high pH meat possesses supe-
rior functional attributes compared with
normal pH meat, regardless of the degree of
comminution or storage time. Meat inher-
ently high in pH possesses superior function-
ality relative to meat whose pH was raised
using phosphates (Young et al. 2005 ).
Previous studies in our laboratory indicate
that protein extractability generally dimin-
ishes over time with some deviations, in that
protein extractability in beef and venison
stored frozen for 1 month or chilled for 2 to
3 weeks is higher than that of fresh beef just
after rigor attainment (Farouk and Wieliczko
2002 ; Zhang et al. 2005 ; Farouk et al. 2007 ;
Farouk and Freke 2008 ). In other words, the
optimum time postmortem to maximize the
extraction of meat proteins in chilled meat
for use in hot - set restructuring is 2 to 3 weeks
postmortem. The role of the extracted protein
in hot - set restructuring has been discussed in
detail by King and MacFarlane (1987). It is
widely accepted that myofi brillar proteins,
particularly myosin, are responsible for the
bind strength of extracted muscle proteins
and that sarcoplasmic proteins contribute
very little to this process.
The surface protein matrix can also be
created by the use of nonmeat protein binders
or by the use of pressure, alone or in combi-
nation with meat homogenates. The use of
pressure is based on the results of a number
of studies that indicate that pressure can be
used to alter the properties of muscle proteins
(Cheftel and Culioli 1997 ; Colmenero 2002 ),
including increased solubility, aggregation,
and gelation of the proteins (Elgasim et al.
1982 ; Macfarlane et al. 1984 ). Pressure also
affects the physical properties of meat, such
as the disruption of myofi brillar structures
and increased tenderness and cohesion
between meat particles. Farouk and Zhang
(2005) described a process of pressure -
binding beef steaks and cubes for hot - set
restructuring: in this process, semimembra-
nosus muscles were sliced parallel to fi ber2006 ). Enzymes such as collagenase, papain,
and fi cin have also been used to reduce
connective tissue toughness in beef for
restructuring (Miller et al. 1988, 1989 ).
Mechanical and enzyme tenderization may
have negative effects on the shelf life, color,
and drip loss of restructured meats in the raw,
and the yield and sensory properties in the
cooked states (Miller et al. 1988 ). Prerigor
muscles can be stretched to improve the
tenderness of the resultant meat and the
restructured whole - tissue products. A mus-
cle - stretching device (Sarcostretch) was used
by Farouk et al. (2005a) to stretch prerigor
bovine Mm. semitendinosus , semimembrano-
sus , and bicep femoris , and the authors found
that the muscles were lengthened by 43% to
97%; overall, stretching improved tender-
ness, uniformity, presentation, and portion
control of the meat, and reduced its drip
loss.
Creating a Surface Protein Matrix
In hot - set restructuring using large pieces or
intact cuts, the surface protein can be obtained
by solubilizing the natural proteins in the
meat with salt or by adding nonmeat proteins
at the surface. If the natural proteins in the
meat are to provide the matrix needed for
binding, their extraction can be achieved by
mixing, tumbling, or massaging the meat
pieces with salt alone or with polyphos-
phates. The salt can also be sprinkled very
lightly on the surface of the muscles without
any form of agitation, particularly in restruc-
turing large pieces of cuts with minimum
surface - binding area. Some of the equipment
used in the extraction process has been dis-
cussed by Booren and Mandigo (1987).
Extraction of the proteins from meat is
affected by, among other factors, the state of
rigor development in the meat; the ionic
environment and the pH of the system; the
temperature history of the meat during rigor
onset; the temperature of the mix during
extraction; and the age of the meat (King and