176 Chapter 8
other methods of cookery. Radio frequency
heating is another rapid cooking alternative
that is regarded as a volumetric form of
heating in which heat is generated within the
product, which reduces cooking times and
could potentially lead to a more uniform
heating (Zhang et al. 2006 ). Zhang et al.
(2006) reported that radio frequency cooking
resulted in a signifi cant reduction in cooking
times for leg and shoulder hams. However, a
number of quality attributes of the radio fre-
quency cooked samples differed from those
of their steam - cooked counterparts. Radio
frequency cooked hams had signifi cantly
lower water - holding capacity and higher
yields than their steam cooked counterparts.
Additionally, radio frequency cooking
resulted in a less well - done coloration with
higher Hunter a * values (Zhang 2006 ) than
the steam - cooked product.
Contact cooking, as seen with pan frying
or clamshell grills, is a popular method of
cooking meat patties. Oroszv á ri et al. (2005b)
showed that the higher heating temperature
resulted in shorter total frying times to reach
the same internal temperature. Oroszv á ri et
al. (2005a) also found that the longer the
thawing time in the frying pan, the less total
water was lost. These researchers reported
that the thawing time was the longest part of
the frying time for beef burgers cooked from
the frozen state. For heating of the core of a
hamburger from 0 ° C to 72 ° C, lower losses
were favored with quick heat transfer. The
interconnections of all these parameters show
the interaction between heat and mass trans-
fer. Oroszv á ri et al. (2005a) reported that the
time required to reach the fi nal temperature
in pan - fried beef burgers was controlled
mainly by the water content of the product.Major Effects of Cooking
Dimensional Changes
During cooking, meat products change size
and shape. This is especially obvious inare usually vacuum packaged prior to
cooking.
The rate of heat penetration depends on
the type of cookery used (Seideman and
Durland 1984 ). For example steam cookery
or other moist heat methods of cookery will
result in faster heat penetration (McCrae and
Paul 1974 ) than dry cooking methods (Buck
et al. 1979 ). Drummond and Sun (2006)
reported moist heat methods of cooking
resulted in more rapid surface temperature
increases compared with dry heat cooking.
However, surface browning, which contrib-
utes to the aroma of cooked meat, did not
develop the same when moist heat cookery
was used.
For a product to reach a specifi c internal
temperature, the cooking apparatus must be
set at a higher temperature than the target
temperature. Evaporative cooling prevents
the product from being the same temperature
as the set point. Therefore, cooking tempera-
tures must be greater than the desired internal
temperature. Boles and Swan (2002a)
reported cooking time was faster when roasts
were cooked at a constant temperature as
compared with roast cooked by a step - up
(maintain 10 ° C differential between the
internal temperature and the cooking tem-
perature) or delta T process. This shows that
cooking temperature does affect the rate of
cooking. Bengtsson et al. (1976) reported
that increasing the oven temperature from
175 ° to 225 ° C resulted in steeper temperature
gradients, shorter cooking times, and lower
yields.
Microwave or radio frequency cooking
are newer methods that have been introduced
to the meat industry. Welke et al (1986)
reported roasts cooked by microwave took
less time to reach endpoint temperatures than
did roast cooked by convection or conven-
tional methods. The shorter cooking times
associated with microwave cooking doesn ’ t
give enough time for the browning reaction.
Meat cooked with microwaves does not have
the typical browned surface associated with