Term
| With higher amounts of connective tissue (CT), does meat tenderness increase or decrease? |
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Definition
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Term
| What is the most abundant protein in the body? |
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Definition
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Term
| What is the main structural protein of CT? |
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Definition
| Collagen (also contains some elastin) |
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Term
| Where in the body is elastin found (7)? |
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Definition
| tendons, ligaments, bones, cartilage, muscle, skin, blood vessels |
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Term
| What is the function of tendons? |
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Definition
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Term
| What is the function of ligaments? |
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Definition
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Term
| How does collagen's structure function in muscles? |
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Definition
Structure
- holds muscle fibers together
- protects muscle fibers from being damaged
Supports Blood vessels and nerves |
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Term
| T or F: Collagen can be found at all levels of the muscle cell |
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Definition
| true, found in Epi, Endo, and Perimysium |
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Term
| Gristle is actually _____ |
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Definition
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Term
| What is the structural component of collagen fibrils? |
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Definition
| Tropocollagen (known as photofibril) |
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Term
| Where is tropocollagen synthesized? |
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Definition
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Term
| What are the structural components of Tropocollagen? |
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Definition
| AA, Glycine (occurs every 3), Proline and Hydroxyproline (25 to 33% of total AA) |
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Term
| Where in the body is hydroxyproline exclusively found? |
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Definition
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Term
| What can Hydroxyproline content be used for? |
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Definition
| identifying amt of collagen in CT |
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Term
| AA synthesized into 3 polypeptide strands, for a ____ |
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Definition
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Term
| How many types of collagen are there, and how many are found in muscle? |
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Definition
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Term
| T or F: Collagen can stretch |
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Definition
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Term
| What colour is collagen, when bound with many collagen molecules? |
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Definition
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Term
| Which types of limbs in the body have higher amounts of CT? |
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Definition
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Term
| Where are intramolecular Xlinks found? |
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Definition
| BETWEEN PP strands that are within the tropocollagen molecule |
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Term
| Where are intermolecular xlinks found? |
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Definition
| Between adjacent tropocollagen molecules |
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Term
| Do older or younger animals produce more collagen? |
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Definition
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Term
| Describe the collagen in younger animals |
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Definition
fewer xlinks this collagen
presence of reducible/soluble, intermolecular xlinks |
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Term
| Collagen turnover is dependent on what? |
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Definition
| Collagen fibril diameter (inverse relationship) |
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Term
| %turnover per day of collagen is |
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Definition
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Term
| What is the collagen/elastin ratio withing the longissimus? |
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Definition
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Term
| How does a Cu deficiency affect elastin? |
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Definition
| Synthesis of desmosine stops |
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Term
| What are some evolutionary factors that affect amounts of connective tissues? |
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Definition
Functional demands of life
Connective tissue strength (body, age, size) |
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Term
| What are the three predisposing factors affecting amounts of CT in the body? |
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Definition
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Term
| What is background toughness? |
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Definition
| How much CT is in the muscle |
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Term
| What three factors affect background toughness? |
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Definition
| Age (less toughness in young), Growth rate (less toughness in animals with fast growth rates), effect on ageing, hanging or conditioning meat on background toughness |
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Term
| What affects muscle tenderness? |
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Definition
-proportions of type I & type III collagens
-total amount of collagen
-degree of heat stable collagen Xlinking
-fiber diameter of perimysium & endomysium |
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Term
| Are type I or type III collagens more affected by heat solubilization? |
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Definition
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Term
| As fiber diameter increases, the amount of heat stable collagen _____ and soluble collagen _____ |
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Definition
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Term
| How do marinades improve the tenderness of connective tissue & muscle fibers? |
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Definition
| -weak acids cause collagen to swell, H bonds are disrupted |
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Term
| When should enzymes like papiain be used to improve meat tenderness, and how do they work? |
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Definition
-apply before the meat is cooked
-causes proteins to denature during cooking (enzymes will lose function during cooking) |
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Term
| What are the characteristics of tough muscle fibers? |
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Definition
-abundance of collagen (endomysium)
-many interfiber connections
-Xlinks are heat stable
-elastin is present |
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Term
| What is Warner Bratzler shear force? |
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Definition
instrumental method of assessing meat tenderness
-measures the force req'd to cut across muscle fibers (lower the better) |
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Term
| What are the drawbacks to using sensory panels to assess meat tenderness? |
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Definition
| time consuming & expensive |
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Term
As an animal ages:
Collagen synthesis ____
Collagen Xlinking ____
Collagen solubility ____
Fiber strength _____
Heat stability _____
Tenderness _____ |
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Definition
Collagen synthesis decreases
Collagen Xlinking increases
Collagen solubility decreases
Fiber strength increases
Heat stability increases
Tenderness decreases |
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Term
| What happens to the reducible Xlinks of collagen as an animal ages? |
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Definition
| they are converted to pyridionoline (not easily broken down) |
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Term
| How is age of an animal assessed in a carcass? |
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Definition
-bone ossification (degree of cartilage converted to bone)
-increases the amount of insoluble connective tissue = lower quality meat |
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Term
| What factors affect collagen characteristics? |
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Definition
Diet
Species
Gender
Muscle variation |
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Term
| How does diet affect collagen? |
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Definition
-feed restriction prior to slaughter reduces Xlink stability
-feeding finishing diets provide lots of energy, producing more soluble collagen & tender beef |
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Term
| Which has more collagen, pigs or cattle? |
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Definition
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Term
| Which species has more of a tenderness problem, pigs or cattle? |
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Definition
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Term
| Which will have higher collagen, barrows or gilts? |
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Definition
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Term
| Is high hydroxyproline related to more or less tender meat? |
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Definition
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Term
| If collagen is primarily found in the perimysium or endomysium will the meat be tougher or more tender? |
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Definition
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Term
| Is collagen higher in the forequarter or hindquarter of beef? |
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Definition
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Term
| The total content of collagen is based on... |
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Definition
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Term
| What factors affect collagen quality/presence in the muscle? |
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Definition
-total content of collagen
-types of collagen present
-heat stable Xlinks
-histological distribution
-type of muscle |
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Term
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Definition
-arteries
-abdominal wall
-ligamenta nuchae
-lungs
-skin |
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Term
True or False
Meat is typically very high in elastin content |
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Definition
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Term
| Which is resistant to acid/base/heat, elastin or collagen? |
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Definition
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Term
| What are the components of elastin? |
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Definition
glycine (also in collagen)
desmosine + isodesmosine
hydroxyproline (also in collagen) |
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Term
| What is the importance of elastin? |
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Definition
| structure & function of elastic fibers & muscle |
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Term
| What synthesizes elastin? |
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Definition
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Term
True or False
elastin is highly soluble |
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Definition
false
Nonpolar AA's & desmosine make it highly insoluble |
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Term
| When cooking meat, when is it better to cook with moist heat, over dry heat? |
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Definition
| When the meat is high in collagen |
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