Module 11-meat quality Flashcards
what is meat quality a function of for the consumer
For the consumer, the quality of meat is a function of wholesomeness, eye appeal and palatability or eating satisfaction
what influences the type of meat the consumer is seeking
The perceived wholesomeness, or nutrient value, safety and value for money influence decisions regarding the type of meat the consumer is seeking. Past eating experiences based on palatability and consistency also affect consumer-buying decisions prior to selection from the meat counter
what is overall meat quality influenced by
Overall meat quality is influenced by animal management (genetics, nutrition, health), production practices including transportation and handling, slaughter and processing, distribution and consumer practices.
what is factor effects eye appeal of meat
A major factor affecting eye appeal is the colour of the meat
what is the dominant pigment in meat
The dominant pigment in meat is myoglobin
what is the function of myoglobin
functions to store oxygen for aerobic metabolism in muscle tissues
what is myoglobin
Myoglobin is the water-soluble protein responsible for meat colour
what is the colour of meat a function of
The colour of the meat is a function of the concentration of myoglobin and its level of oxygenation or oxidization
in living muscle why would it have a purple colour
In living muscle, myoglobin without much oxygen has a purple colour
when is myoglobin bright red
In living muscle When myoglobin is oxygenated (carrying oxygen), it is bright red
what colour of meat do consumers prefer
Most consumers prefer meat that appears as bright red
what happens to myoglobin after it have been oxidized
After long exposure to oxygen, myoglobin becomes oxidized and appears brown
why does meat appear brown
After long exposure to oxygen, myoglobin becomes oxidized and appears brown
what colour meat do gourmet cooks prefer and why
Gourmet cooks often prefer meat with a brown colour because it is likely to have a better taste than bright red meat
what factors make myoglobin concentrations vary
Myoglobin concentration varies by species, age and the specific cut of meat
why does myoglobin concentrations vary between different species and cuts of meat
Differences between species and between different cuts of meat are largely due to the aerobic or oxygen-carrying capacity of the muscle which determines the amount of myoglobin present.
what is the iron valence, ligand at 6th coordination site and colour of pigment of deoxymyoglobin
fe2+ ferrous, H2O, purplish-red
what are 4 kinds of myoglobin’s
oxymyoglobin, deoxymyoglobin, metmyoglobin, carboxymyoglobin
what is the iron valence, ligand at 6th coordination site and colour of pigment of oxymyoglobin
Fe2+ ferrous, O2, bright red
what is the iron valence, ligand at 6th coordination site and colour of pigment of Metmyoglobin
Fe3+ ferric, OH or H2O, grey-brown
what is the iron valence, ligand at 6th coordination site and colour of pigment of carboxymyoglobin
Fe2+ ferrous, CO, bright red
is one or all of the pigment forms found present in the meat
The three pigment forms of myoglobin are usually all present at the same time and the colour of the meat is provided by the dominant form
what level should metmyoglobin be found in and what level are considered unacceptable
In vivo, metmyoglobin level is two to three percent, meat deterioration is perceptible when metmyoglobin reaches thirty percent, levels greater than sixty percent are considered unacceptable.
what is the myoglobin found in vacuumed packed meats
Reduced myoglobin is the predominant pigment in vacuum packaged meat cuts
how does vacuumed packaging allow the meat to be shipped
Vacuum packaging technology in conjunction with good hygienic practices and temperature control (0 to 1°C) enable processors to ship fresh, never frozen, pork and beef to distant markets.
is the meat packages used for vacuuming packaging permeable to O2
The packages used for meats processed by vacuum packaging is not permeable to oxygen, unlike traditional retail film wraps
what does the addition of oxygen to myoglobin do
The addition of oxygen to myoglobin causes oxygenation and creates oxymyoglobin that is a bright cherry red, creating the “bloom” observed on meat
why is retail packaging O2 permeable
Retail packaging with oxygen permeable film allows meat to develop the bright cherry red “bloom” desired by the consumer; this can also be achieved with the use of high oxygen modified atmosphere packaging
what causes the brownish-grey colour of meat
Metmyoglobin, resulting from oxidation of the iron in myoglobin creates an undesirable brownish-grey colour
when does iron oxidation occur
Iron oxidation occurs when oxygen is present and a reaction occurs
what can can prevent the oxidation of iron
the conversion can be reduced by keeping meat at a lower temperature or at higher pH, it can also be reduced by feeding vitamin E to livestock.
how does Vitamin E in feed reduce iron oxidation
Vitamin E in feed increases alpha-tocopherol concentration in muscle tissue where it acts as an antioxidant suppressing the transformation of myoglobin and oxymyoglobin to metmyoglobin.
what does cooking meat do to myoglobin
Cooking irreversibly denatures myoglobin creating the brown colour of cooked meat