The over-tenderization of irradiated-sterilized meat is one
of the more important adverse effects resulting from the use of
irradiation for the preservation of meat. Although research has
been reported on the activity and effect of the inherent proteolytic
enzymes of irradiated meat, very little work has been directed toward
the intimate causes of the textural problems induced by the
irradiation treatment.
In this study, the influence of irradiation-sterilization on
some of the muscle characteristics involved in meat texture was
investigated in an attempt to elucidate the over-tenderizing action of
irradiation. In addition, the influence of treating the meat by several
means prior to irradiation was also investigated to determine their effects upon the texture of the meat. Information relative to the above
objectives was obtained by using analytical methods designed to show
changes in muscle protein charges, water-holding capacity, acidic
and basic groups, bound and free minerals, and disc electrophoretic
analysis of the glycine soluble extracts of the treated and control samples.
The results showed that the irradiation-sterilization of beef
muscle at 4.5 megarads caused tenderization of the meat. Beef
soaked in an equal amount of distilled water for 72 hours at 38°F
prior to heat inactivation of the enzymes and irradiation was much
firmer in texture than the unsoaked samples. Beef heated to an internal
temperature of 160°F prior to irradiation also resulted in meat
having a firm texture. However, irradiation tends to reverse the effects
of both soaking and heating and/or the combination of these two
treatments. When soaking, heating and irradiation are combined in
one treatment, these factors tend to exert their effect individually and
by different mechanisms.
Soaking the meat appears to cause a partial denaturation and a
net loss of anions of some of the muscle proteins resulting in a shift in
the isoelectric region of such meat to a higher pH which results in a
greater loss of water upon cooking and thus a firmer texture.
Heating the meat to an internal temperature of 160°F results in
a partial denaturation of the proteins and probably leads to the formation of stable cross linkages and a "salting-out" effect which
may be responsible for a decrease in the water-holding capacity.
Thus, meat would have a tighter or more "closed" structure and
firmer texture.
Irradiation exerts a fragmentation effect upon the beef
muscle proteins. These fragments seem to be held together by hydrogen
bonds and/or electrostatic forces. The fragmentary alterations
of the muscle proteins, the incorporation of water within the fragments,
and possibly a "salting-in" effect, appear to be the major
factors responsible for effects of irradiation on beef muscle texture.
The zinc cations appear to be involved with the heat-labile
proteins or enzymes which are denaturated by heating to 160°F.
The pH-water holding capacity curves were found to be a
valuable technique for investigating some of the biochemical changes
in the muscle proteins. / Graduation date: 1963
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/26672 |
| Date | 27 March 1963 |
| Creators | El-Badawi, Ahmed Adel Ismail |
| Contributors | Anglemier, Allen F. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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