Biomedical Engineering Reference
In-Depth Information
Application in raw products
: Frozen meat samples were thawed by ohmic technology
in a liquid contact thawing methods (Wang et al.
2002
). Thawing process was found
uniform and quicker with retained quality of meat, such as colour and pH. These
results demonstrated the potential uses of OH in contact thawing, especially for
meat products. The changes in the histology and the texture of beef cuts during
ohmic thawing were compared with those during conventional thawing method by
Icier et al. (
2010
). Ohmically thawed beef cuts samples were harder than conven-
tionally thawed ones while the conventional thawing caused springier beef cuts.
These workers pointed the voltage gradient (10, 20 and 30 V/cm) applied during
ohmic as an important parameter for textural properties of beef cuts in terms of the
hardness, springiness, gumminess and chewiness.
Application in ready
-
to
-
eat products
: Sarang et al. (
2007
) developed a blanching
method to increase the ionic content in chicken chow mein and compared the OH
(60 Hz up to 140 °C) uniformity of blanched particulate against untreated samples.
It was observed that following pre-treatment, it may be possible to uniformly heat
the entire product during OH and that such pre-treatment does not compromise with
product quality. Ohmic heating was found to produce quality levels comparable to
those achieved by conventional methods with reduced cooking losses in beef
biceps
femoris
muscle tumbled with 3 % salt solution for 16 h (Zell et al.
2009
). Intact
turkey meat was cooked using low temperature long time (LTLT) and high tempera-
ture short time (HTST) protocols in a combined ohmic/convection system and they
were compared to conventional steam cooking (Zell et al.
2010a
). Rapid ohmic
heating resulted in levels of quality which are broadly comparable to those achieved
by conventional cooking with an 8-15-fold reduction in cooking time showing its
potential to cook whole turkey breast meat. Ohmic heating treatments of beef
semi-
tendinosus
muscle eliminated
L. innocua
below the detectable level, thus demon-
strating the safety of these protocols (Zell et al.
2010b
). It was also found that whole
beef cooked rapidly by ohmic heating (sevenfold time reduction with the LTLT
protocol) and gave quality levels comparable to those achieved by conventional
methods while it also reduced cooking losses. Further, the most rapid ohmic cook-
ing protocol (HTST) gave similar instrumental quality values to conventional cook-
ing, despite a 15-fold reduction in cooking time.
Piette et al. (
2004
) observed no loss in the quality of cooked basic bologna emul-
sion in terms of appearance and texture when ohmic cooking (64-103 V; 3.9 °C/min
to 10.3 °C/min; to 70-80 °C) was substituted by traditional smokehouse cooking
(180 min cycle; to 70 °C). Bozkurt and Icier (
2010
) reported that ohmic heating (20,
30 and 40 V/cm) of ground beef sample was faster than the conventional cooking.
Ohmically cooked samples were fi rmer than those by conventionally cooked but no
differences were found in yield and fat retention. The colour was more homoge-
neous within the ground beef cooked ohmically. Thus in muscle foods, ohmic heat-
ing is being used in thawing, blanching and cooking process and it showed several
advantages when compared to conventional technologies. It results in higher or
similar cooking yield and sensorial quality retention as compared to conventional
cooking methods. Additionally more uniform lighter and browner colour could be
