Salt generally increases water-holding capacity in cooked products, particularly those without added phosphates. However, the effect can vary depending on the presence of other ingredients like phosphates.
Here's a breakdown:
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In Products Without Added Phosphates:
- Increasing salt content leads to increased water-holding capacity, gel strength, and firmness. This is because salt helps to solubilize muscle proteins, allowing them to bind more water.
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In Products With Added Phosphates:
- There's a significant increase in water-holding capacity when salt concentration reaches between 1.0% and 1.5% NaCl.
- Beyond this range, further increases in salt content don't significantly improve water-holding capacity. The phosphates likely have already maximized the protein's ability to bind water.
Why does this happen?
- Protein Solubilization: Salt helps solubilize myofibrillar proteins (the main proteins in muscle tissue). These solubilized proteins can then trap and bind water more effectively.
- Ionic Strength: Increased ionic strength (due to the presence of salt ions) can alter the interactions between proteins, leading to better water retention.
- Phosphate Synergism: Phosphates, when present, enhance the effect of salt on protein solubilization and water binding. They work together to improve the overall water-holding capacity.
Practical Implications:
Understanding how salt affects water-holding capacity is crucial in food processing because it impacts:
- Texture: Water-holding capacity directly affects the juiciness and tenderness of cooked products.
- Yield: Higher water-holding capacity means less water loss during cooking, resulting in a higher yield and economic benefit.
- Shelf Life: Improved water-holding capacity can also enhance the shelf life of certain products by reducing water activity and inhibiting microbial growth.
