Postmortem changes and slaughtering Flashcards
One of the most serious outcomes of circulatory collapse is interruption of oxygen
supply of the muscles.
Postmortem glycolysis and pH decline
True or False. In most species, a gradual decline continues from approximately pH 7 in the living muscle during first few hours (5-6 hours) and then there is a little drop in the next 15-20 hours, giving an ultimate pH in the range of 5.5 – 5.7.
True
During the postmortem degradation of ATP in both fish and meat, what acid is dephosphorylated to inosine?
Inosinic acid
What does ADP, AMP, and IMP stand for?
ADP – adenosine diphosphate
AMP – adenosine monophosphate
IMP – inosine-5 phosphate
A chemical postmortem change that losses a physiologically balanced internal environment.
Loss of homeostasis
It refers to the development of the stiff and rigid
condition in the muscle.
Rigor mortis
True or False. During rigor mortis, the loss of extensibility associated with
the formation of actomyosin proceeds slowly at first (the delay period) and then extremely rapidly (fast phase).
True
True or False. The onset of rigor mortis normally occurs at 1- 12 hours postmortem and may last for a further 15-20 hours in mammals while it generally exhibit a shorter rigor mortis in fish with a period commencing 1-7 hours after death, both having many factors affecting their duration.
True
Enumerate the chemical postmortem changes.
Loss of Homeostasis
Postmortem glycolysis and pH decline
Rigor mortis
Loss of protective mechanisms
Degradation due to proteolytic enzymes
Loss of structural integrity
Other chemical changes
The resolution ofrigor mortisisreportedto
occur due to what?
Disintegration of Z-line structure
A multicatalytic proteinase complexes (both of which are present in the sarcoplasm)
Calpains
They are autolytic lysosomal
enzymes present only in lysosomes of
muscle fibers which initiates the degradation of muscle protein structure. They remain inactive in a living muscle tissue and are activated as the muscle pH declines.
Cathepsins
It is a physical postmortem change which refers to the unavailability of oxygen to the tissue of a slaughtered animal causing the pigment oxymyoglobin to be converted to deoxymyoglobin, resulting to the brown color of the meat.
Change in color
Since water accounts about 65-80% of the total muscle mass, much of the water in the muscle cells is tightly bound to various proteins. This results to what physical postmortem change?
Change in water binding capacity (WHC)
What are the three stages involved in the conversion of muscle to meat and edible fish?
Pre-rigor state
Rigor mortis
Post-rigor state
It is the fall in ATP and creatine phosphate levels which involves active glycolysis.
Pre-rigor state
A corresponding pH drop, associated with
the formation of actomyosin complex.
Rigor mortis
Meat and fish muscles gradually
tenderize in this state.
Post-rigor state
True or False. In warm-blooded animals, the production of lactic acid causes the pH of the muscles to drop from the physiological pH of 7.2-7.4 to the ultimate postmortem pH of around 5.3-5.5.
True
