Goal:
(1) To demonstrate the relationship between myoglobin and meat color.
(2) To show how the chemical state of myoglobin is related to meat color.
(3) To identify factors related to discoloration of fresh meat.
Education material: Principles of Meat Science (3rd edition), chapter 6, pages 126 to 131.
The most important expressions used to describe color
Tint, Chroma and Value
- Hat - Words that we usually regard as a description of color: red, purple, blue, etc.
- Chroma - Strength or Dominance of Tint
- Value - the total intensity of how light or dark is a color.
L*, A*, B*Color space (pronounced as "L-Star, A-Star, B-Star") for instrumental measurements
- L* - Black to white
- A* - Red to green
- B* - Yellow to blue
Heem pigment found in myoglobin
Hemoglobin - Transport O2From lungs to cells
Myoglobine - stop of2in cells
Meat color is influenced by the following factors:
Amount of myoglobin
Age within species - Myoglobin loses its association with oxygen as age increases.
Myoglobin differences: age within species
| Age -class | Myoglobin layout |
|---|---|
| Veal | 2 mg/g |
| Calf | 4 mg/g |
| Young beef | 8 mg/g |
| Old beef | 18 mg/g |
Types of differences - age -related and differences between "red" and "white" muscle fibers.
Myoglobin different: species effects
| Slager | Colour | Myoglobin layout |
|---|---|---|
| Pork | Pink | 2 mg/g |
| Lam | Light red | 6 mg/g |
| Beef | cherry | 8 mg/g |
Muscles
Myoglobin differences: muscle effects
| Muscle | Name | Myoglobin layout |
|---|---|---|
| Locomotive | M. Extensor digitorum | 12 mg/g |
| Support | Marcus the longest chest and lumbar | 6 mg/g |
Chemical condition of myoglobin
Chemical condition of Myoglobin - Irony of Fe ++ (Covalent Bonds)
| Link | Colour | Name |
|---|---|---|
| : H2O | Lilla | Deoxymyoglobin |
| : O2 | Rood | Oxymyoglobin |
| :NEE | Pink | Nitrogen oxide myoglobin |
| : CO | Rood | Carboxymyoglobin |
Chemical condition of myoglobin - iron or FE +++ (ionic bindings)
| Link | Colour | Name |
|---|---|---|
| -Cn | Rood | Cyanmetmyoglobine |
| -Oh | Brun | Metmyoglobin |
| -Sh | Vegetables | Sulfmyoglobine |
| -H2O2 | Vegetables | Secondary school |
Mancini, R. A. and M. C. Hunt.2005.hoid research into meat color.Meat sci.71: 100-121.doi:10.1016/j.meatssci.2005.03.003
Metmyoglobin Reducing activity (MRA)
The system in muscles that convert metmyoglobin into deoxyhemoglobin (without oxygen) and oxymyoglobin (with oxygen) by a series of reactions until reduction resources are exhausted.
High MRA =Marcus's longest length
LAV MRA =M. psoas major
Oxygen consumer speed (OCR)
The breathing speed of muscles over time under the display compete with myoglobin to keep the muscles in the oxymyoglobin mode.
High OCR =M. psoas major
Lav ocr =M. Gluteus Medius
Color stability varies over the muscles
| Color stability | Muscle |
|---|---|
| "High" color stability | Marcus's longest length Marcus de Lange Borst M. semitendinosus M. Tensor Fascia bred |
| "Moderate" color stability | M. semimembranosus Marcus Right Dij The response of the lateral |
| "Average" color stability | M. Trapezius M. Gluteus Medius Marcus latissimus dorsi |
| "Make" color stability | M. Triceps Brachii- Long head M. Gluteobiceps (M. Biceps Femoris) Marcus Pectoral M. Adductor M. Triceps Brachii- Lateral head M. serratus ventralis |
| "Very low" color stability | M. supraspinatus M. infraspinatus M. psoas major |
Source: McKenna, D. R., P. D. Mies, B. E. Baird, K. D. Pfeiffer, J. W. Ellebracht and J. W. Savell.2005.biochemical and physical factors that influence the characteristics of the discoloration for 19 livestock muscles.10.1016/j.meatssci.2005.02.016
Two meat color problems with boiled beef painted
Premature brown
- Usually caused by highly oxidized meat or meat exposed to atmospheres with high oxygen
- Meat turns brown approximately 130 ° F internal temperature
- Reason that color is not a good indicator of cooked meat
Persistent pink
- Usually caused by high pH - Meat
- The product remains pink (not -coating color), even with degrees of doneness to ensure that the correct cooked end point is followed.
Vitamin feature of cattle
Vitamin E can be brought to cattle to increase the Alfa-Tokopherol concentration in muscles.
Activity of bacteria
| Pigment | Catalyst | Now a pigment |
|---|---|---|
| Oxymyoglobin | Oxidation + bacteria | Metmyoglobin (-oH) |
| Metmyoglobin | Bacteria | Coleglobin (-h2O2 |
| Metmyoglobin | Bacteria | Sulfmyoglobin (-sh) |
Hardening
| Myoglobine Oxymyoglobin Metmyoglobin | Plus hair | Nitrogen oxide myoglobin | Plus warm | Nitrosyl Hemochromogen |
Inpac film
Vacuümpakketten (polyvinylideForid-polyvinylchloride);2
Detail film (polyvinyl chloride);permeable for o2
Review material - What the student needs to know:
(1) Which ensures that meat has a specific color.
(2) The role of bacteria in color development and maintenance.
(3) The influence of the oxygen on the meat color.
(4) The chemistry behind myoglobin and meat color.
Links to related sites
J.W.Savell, Herzi October 2020
