By Kaylee Smith, BRC Intern
When talking beef quality, marbling is one of the first terms that comes up.
Intramuscular fat, popularly referred to as marbling, has been given major emphasis within the various beef grading systems in the projection of raw beef characteristics, to eating satisfaction in the cooked meat.
Marbling is deposited within the muscle in a loose network of perimysial connective tissues, between the muscle bundles.
Intramuscular fat was thought to accumulate through the finishing stage, but research has shown that it increases linearly over time. Lipids found in marbling have the most important role in meat quality. Fat acts as one of the precursors of flavor by combining with amino acids from proteins and other components when heated.
When fat melts, it releases flavors and gives sudden bursts of these flavors.
Fat is a lately developing tissue in cattle, meaning, the older the animal the more chance of fat / marbling developing.
An acceleration of fat happens when the animal approaches maturity. While muscle growth slows down as an animal ages, fat continues to be put on and deposited when an animal is well fed. The total amount of marbling in a muscle results from an increase in the number of marbling cells as well as size of cells. These cells are distributed among several groups of fat cells.
When a group of these cells merge together they often form what looks like a seam, hence where we get the name seam fat. The number of cells in any particular group determines the appearance of marbling and increases with animal age.
Marbling score has a great effect on meat tenderness and cooking quality.Marbling is usually considered as the “cooking insurance” of meat.
There are 10 degrees of marbling:
- Very abundant (best)
- Moderately abundant
- Slightly abundant
- Practically devoid (worst)
Age is also a factor in marbling and quality grades. “A” maturity group is cattle from 9 to 30 months of age.
For carcasses that exceed the A maturity group (B, C, D, E, & F), the marbling requirements increase. Any animal that falls within the A maturity group is anywhere from 9 to 30 months of age, whereas the other maturity groups range from 30 months and up.
So the older an animal gets the dark the color of the lean and the more fat they need to put on to counter act the darkness of the lean.
We want cattle that are in the A maturity group, they are ultimately going to have more marbling, a higher quality of tenderness, and will have a bright cherry red lean color.
For more information on marbling, you can visit TAMU’s Meat Science website at https://meat.tamu.edu/beefgrading/.