Meat Science Exam 3
How long does it take for oxygen to react with myoglobin to form oxymyoglobin when exposed to air?
20-30 minutes.
What percentage of all meats in the US are processed?
30%
How long can processed meats last?
4-12 weeks (or longer).
How much of pigment is hemoglobin?
5-15%.
What percentage of a pork carcass can be cured?
80%
How much of pigment is myoglobin?
80-95%.
What is premature browning caused by?
A large amount of meat in Metmyoglobin state.
What kind of issue is persistent pinking?
A quality issue.
What can cause iridescence?
A rough or dull knife when slicing.
At what pH does meat become extremely dark (dark cutters)?
Above 6.8
What does cured mean?
Application of salt, nitrate, and seasonings to develop unique color, flavor, and texture properties and give resistance to rapid deterioration.
What cut is corned beef made from?
Beef brisket.
What sausage meat(s) is classified as cooked and not smoked?
Braunschweiger, beer salami.
What color is a stable color?
Brown
How do oxygen radicals get electrons for oxidation?
By stealing them.
What is an example of other processed meats?
Canned meat (Spam).
What is the most important appearance trait in meat?
Color
The higher the pH, the higher the ______
Color stability
What "sets" the proteins in meat?
Cooking
What is the most common cured beef product?
Corned beef.
What are other names for sodium nitrite?
Cure salt, NaNO2, saltpeter, prague powder.
How are sausage meats usually processed?
Cured, seasoned, heat processed, and/or smoked.
The higher the pH, the _____the meat.
Darker
What happens when the temperature is near freezing?
Decreased enzyme activity and O2 utilized, and it maintains a bright red color.
What type of meat often shows iridescence?
Deli meats.
What is hemichrome?
Denatured globulin and oxidized heme iron.
What are the myoglobin forms?
Deoxymyoglobin, oxymoyglobin, and metmyoglobin.
What are the advantages of curing?
Development of unique color, flavors, and textures, and improved product safety and preservation.
What occurs with increased pH and temperature?
Enzymes are more active and there is a more rapidly deplete O2 content.
True or false: Meat color is an appropriate way to determine if ground beef is safe to eat.
False
True or false: Meat color is not closely tied to pH.
False
True or false: Iridescence is harmful to eat and microbiological.
False.
What is the reduced state?
Fe +2, Ferrous state.
What is the oxidized state?
Fe+3, Ferric State.
What are the traits of the metmyoglobin state?
Ferric, Fe+3.
What are the traits of the oxymyoglobin state?
Ferrous, Fe+2, oxygen binding.
What are the traits of the deoxymyglobin form?
Ferrous, Fe+2, water binding.
What sausage meat(s) is classified as cooked and smoked?
Frankfurter, bologna.
What sausage meat(s) is classified as fresh?
Fresh pork sausage.
What is reduction?
Gain of electrons.
What is premature browning?
Ground beef that has turned brown at too low of a temperature to kill microorganisms.
What does comminuted mean?
Ground, chopped, and/or flaked.
What are examples of whole muscle processed meat?
Ham, bacon, smoked turkey.
Myoglobin + ____=Temperature Dependent Denaturation
Heat
Myoglobin + Heat=
Hemichrome.
When MRA is ___, color stability is increased.
High
What is persistent pinking caused by?
High meat pH.
Myoglobin is the most bioavailable source of what in the human diet?
Iron.
The closer to the ____ point (5.2), the paler the meat.
Isoelectric point.
Why does Vitamin E work as an antioxidant and to prolong shelf life?
It delays metmyoglobin formation.
What is iridescence caused by?
Light refracting off the smooth meat surface.
Exposure to what will cause the cured pink color to fade?
Light, especially if exposed to open air and not vacuum packaged.
What is oxidation?
Loss of electrons.
When OCR is _____, color stability is increased.
Low.
What sausage meat(s) is classified as cooked meat specialties?
Luncheon meats, loaves, jellied products, etc.
What kind of issue is premature browning?
Meat Safety Issue.
What should you use when cooking ground beef and to what temperature should you cook it?
Meat thermometer; 160 degrees.
What does MRA stand for?
Metmyoglobin Reducing Ability.
What are processed meats?
Muscle-derived products in which fresh meat has been altered (grinding/chopping, seasonings added, color alterations, heat, etc).
What two pigments contribute to meat color?
Myoglobin and Hemoglobin.
The older the animal, the more ___ and the ____the meat.
Myoglobin, darker.
What is solubilized and serves as the sticky "glue" that allows for meat to stick together (bind).
Myosin.
What provides the electrons for reduction reactions?
NADH.
What is the pigment responsible for meat color?
Nitrosylhemochrome.
What state of myoglobin heme iron plays a large role in meat color?
Oxidation state.
What does OCR stand for?
Oxygen Consumption Rate.
What does OCR rely on?
Oxygen concentration.
What does restructured mean?
Particles are reduced in size and then reformed.
What is Persistent Pinking?
Pink color that remains as safe cooked temperatures.
What does salt do in curing?
Preservation )inhibits bacterial growth through dehydration and redcing water activity) and flavor.
Why do people process meats?
Preservation/extended shelf life, convenience, variety, quality and safety, processor specifications, and value-added.
What is myoglobin?
Protein responisble for storing O2 in muscle tissue.
What is hemoglobin?
Protein responsible for carrying O2 throughout the body in blood.
What does the word 'globin' mean?
Protein.
What is iridescence?
Rainbow, "mother of pearl" appearance.
What is the color scale rate, starting from fresh to processed?
Red, pink, tan, and brown.
What colors may become more red over time?
Red/pink
What does MRA do?
Reduces enzyme system (Ferric to Ferrous; brown to purple/red).
What are examples of sausage meat?
Salami, pork sausage, summer sausage, hot dogs, etc.
What is a needed ingredient for protein extraction?
Salt
What is the most basic and most important curing ingredient (often the only necessary ingredient)?
Salt
Myoglobin is a "....... protein."
Sarcoplasmic.
What does OCR do?
Scavenging enzymes.
How are whole muscle meats often processed?
Seasoned, heat processed, and smoked.
What are examples of processing methods?
Smoking, drying, salting, curing, cooking, fermenting, restructuring, chopping, tumbling and massaging, etc.
What is responsible for cure color (cure pink)?
Sodium nitrite.
What two compounds are in green meat?
Sulfmyoglobin and Choleglobin.
What sausage meat(s) is classified as dry, semidry, or fermented?
Summer sausage, dry-salami, Lebanon bologna.
What is "bloom time?"
The 20-30 minutes it takes to form oxymyoglobin.
What does MRA rely on?
The NADH pool.
What do enzymes regulate?
The O2 available in the outermost layers.
What is the primary reaction responsible for meat color?
The addition or removal of oxygen from the myoglobin binding site.
What about myoglobin makes it responsible for meat color?
The chemical state and ligand bound to it.
What is freezer burn?
The result of surface dehydration.
True or false: Freezer burn meat is safe to eat.
True.
True or false: Myoglobin is water soluble.
True.
What vitamin acts as an antioxidant and prolongs the shelf life of beef?
Vitamin E.
What are the types of processed meats?
Whole muscle and sausage.
_____have more myoglobin than domesticated breeds.
Wild populations.
How can freezer burn be prevented?
With tight fitting packaging and shorter freezer time.