Fundamentals of Water Holding Capacity (WHC) of Meat

Table of Contents

1. Introduction
   1. Objectives
   2. Learning goals
   3. Teacher page
2. List of Abbreviations used in this Learning Resource
3. Section I: Introduction and Significance of WHC
   1. What is WHC?
   2. Overview of Proteins, Fat, pH and Water and WHC
   3. Compartments for Holding Water in Meat
   4. Activity - Section I
4. Section II: Major Factors Affecting WHC
   1. Role of Animal Genetics and WHC
   2. Role of Pre-harvest Handling of Pigs on WHC
   3. Conversion of Muscle-to-Meat Issues and WHC
   4. Muscle Extensibility and Rigor Mortis
   5. Activity - Section II
5. Section III: Mechanism for Holding of Water in Pork
   1. Concepts for holding of Water in Meat
   2. How is Water Held in Meat?
   3. Graphic Representation of WHC and Important Concepts
   4. Examples of Extrinsic Factors Affecting WHC of Processed Meats
   5. Activity - Section III
6. Section IV: Fundamental Science of Water Holding Capacity
   1. Expanding the Knowledge of WHC
   2. The Assignment
   3. Activity - Section IV
7. Section V: Methods for Determining WHC
   1. Complexity of Measuring WHC
   2. What Moisture Categories of Water need to be Measured?
   3. Video: Great Visualization of four WHC Methods
   4. Methods for Measuring WHC of Meat
   5. Activity - Section V
8. Section VI: Recent Advances in Measuring & Monitoring WHC
   1. Need for Fast, Real-time, Non-destructive WHC Methods
   2. Potential Fast and Non-destructive Methods
   3. Activity - Section VI
9. Selected References related to WHC
10. References: Q-Pork Chain & Other Instrumental Methodology for WHC
11. Completion
    1. Comments
    2. Self assessment
    3. Evaluation
12. Acknowledgement

Self assessment

In this section you find the answers to questions at the end of each section.

Answers to questions in Section I

1. Increase yields, more weight to sell, less purge (juice) in packages, better color, fewer complaints
2. WHC = the ability for meat to hold its own native water and any water added during processing.
3. Better
4. False
5. Immobilized water is more restricted and less likely to be lost.
6. Many possibilities

Answers to questions in Section II

1. False
2. Less
3. Increase
4. True if the pH is above pH₁ (normally the case); False if the pH is below the pH₁.
5. PSE = Pale, Soft, and Exudative, and DFD = Dark, Firm, and Dry
6. Animal genotypes with the stress gene will be most susceptible to stress and have the lowest WHC. Pigs with the Napole gene will appear normal in color and firmness but will have a lower than normal meat pH and thus a lower WHC. Even with normal genes, animals that are somewhat excitable will be more susceptible to less than desirable ante-mortem handling.
7. 5.6 to 5.8.
8. Because the biochemistry of some pigs runs faster than normal, more rapid chilling will slow these reactions and help prevent an undesirable combination of low pH with warm carcass temperatures. This should help prevent protein denaturation and improve overall WHC.
9. More protein is denaturated by this combination of variables.

Answers to questions in Section III

1. True
2. False
3. 5.7
4. Increase
5. Higher
6. False
7. True
8. Decrease (decrease the isoelectric pH)
9. Lots of different possibilities.

Answers to questions in Section IV

1. Depending on how the student conducts this self-determined learning of WHC, many answers and scenarios are possible.

Answers to question in Section V

1. The drip methods come close to simulating the natural forces of water movement from meat.
2. One method cannot measure water losses at multiple parts of the meat processing chain.
3. Animal genetics, species, age, gender, nutritional regimen, ante-mortem handling of animals, weather, hauling conditions, lairage time and peacefulness, stunning method, chilling (slow is bad), 24 hr pH, extent of muscle contraction, post-mortem age, packaging conditions, added ingredients, processing conditions, heating, among others.
4. Gravitation affects water movement related to physical and chemical properties of the meat.
5. Decreases: because of heat induced protein denaturation and less electrostatic interaction between proteins and water, the shrinkage of the microstructure that restricts and squeezes water from the storage spaces in meat, and the evaporation of water due to heating.
6. Low and A

Answers to questions in Section VI

1. Currently, no proven rapid, affordable analytical method for measuring WHC is accurate and precise enough to be used by industry for real-time sorting and classifying of meat raw materials.
2. NIRS = near infrared spectroscopy; NMR = nuclear magnetic resonance; Biomarkers = gene or gene products formed by interaction with environmental conditions that could relate to WHC.
3. NIRS is based on unique spectral reflectance patterns at a specified portion of wavelengths. NMR measures mobility of hydrogen-containing compounds, like water, within the environment of the meat. Biomarkers are gene or protein related determinations that show relationships with the physical nature of meat WHC.
4. Currently, the major limitations are accuracy, precision, the need for multiple calibrations, cost, and analytical skill and knowledge to routine run these analyses.
5. Most likely, reference or standardized methods of WHC will continue to be needed; they are not fast or non-destructive but will be used for research and to refine other methods.