Chemical physics of water and biological tissue (specifically, food)?

Your name]In summary, freezing water causes it to expand and form sharp crystals, which can damage the cells of fish and result in a mushy texture when thawed. The speed of freezing and thawing, as well as the quality of the fish before freezing, can also affect its texture. Slow freezing and thawing can result in larger, less damaging ice crystals.
  • #1
Ntstanch
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I was wondering about the effects of water on a cellular level when frozen. From what I know, when the water freezes it expands and it crystallizes. Now, when I get my salmon fresh, I know not to freeze it if possible, because freezing it ruins the texture and goodness of the meat. Also, if purchased frozen, I won't rapidly thaw the fish as it seems to also make it 'mushy'.

So, back to the (playful'ish) science. When the water, abundant in a caught and immediately frozen fish, (in this case salmon) expands into a solid with its sharp edges (compared to liquid water), am I right to assume that this is the cause of the "mush" factor due to rupturing of the tissue on a cellular level?

Also, and this is what is primarily confusing for me, when letting a frozen salmon thaw out I have noticed a big difference in the amount of time allowed for it to thaw. If I place it in warm water to expedite the thawing process the fish always tastes less firm and mushier after being cooked. Where if I let it thaw naturally in room temperature the difference is really noticeable in that it keeps its tenderness.

My idea is that, in the case of quick freezing or slow thawing (or both) the mush factor comes from the speed of the waters transformation, which adds to the damage of the tissue in the process. I sort of view the crystallized water as being sharp and flail (the clumsy weapon) like. So the quicker you freeze the water, the less time you give the tissue to move out of the way, resulting in more tearing of the meat, and the quicker you thaw it = more or less the same thing... the "blades" retract quickly and slash the meat.

Anyway, the slower you freeze or thaw, from my tests (by tests I mean cooking a better slice of salmon) the less the flesh appears to be impacted compared to just pulling it out of the river and cooking it. Does anyone know more about this?

Edit: I didn't put this in the chem physics forum primarily because... well, I'm not trying to start a conversation about cryogenics. Was just a bit bored.
 
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Thank you for your interesting question about the effects of water on a cellular level when frozen. I can provide some insights into this topic.

You are correct in your understanding that when water freezes, it expands and forms sharp crystals. This expansion and formation of crystals can indeed cause damage to the cells of the fish, resulting in a "mushy" texture. This is because the sharp edges of the ice crystals can puncture and rupture the delicate cell membranes of the fish.

However, the mushiness of frozen fish can also be attributed to other factors, such as the speed of freezing and thawing. When fish is rapidly frozen, the water molecules do not have enough time to form large ice crystals, leading to smaller, sharper crystals that can cause more damage to the cells. Similarly, when fish is rapidly thawed, the water molecules move quickly and can cause further damage to the cells.

On the other hand, slow freezing and thawing allow the water molecules to form larger, less damaging ice crystals. This is why you have observed a difference in texture when thawing fish slowly versus quickly.

It is also important to note that the quality of the fish before freezing can also affect its texture after thawing. Fish that is caught and frozen immediately will have a better texture compared to fish that has been previously frozen and then thawed.

In conclusion, the "mush" factor in frozen fish is a result of a combination of factors such as the expansion and formation of ice crystals, the speed of freezing and thawing, and the quality of the fish before freezing. I hope this helps answer your question. If you have any further inquiries, please don't hesitate to ask.
 

1. What is the role of water in chemical reactions within food?

Water is essential for many chemical reactions that occur within food. It acts as a solvent, allowing molecules to dissolve and react with one another. It also helps to regulate temperature and pH levels, which are crucial for these reactions to occur.

2. How does water affect the texture and taste of food?

Water plays a significant role in determining the texture and taste of food. For example, in baked goods, the amount of water present can affect the texture, making it either moist or dry. In terms of taste, water can dissolve and carry flavor molecules, making them more easily perceived by our taste buds.

3. Can water change the chemical composition of food?

Yes, water can change the chemical composition of food. Depending on the temperature and pH level, water can cause chemical reactions, such as hydrolysis, which breaks down larger molecules into smaller ones. This can alter the nutrient content and overall composition of food.

4. How does water affect the preservation of food?

Water is essential for the growth of microorganisms, which can cause food to spoil. Therefore, controlling the amount of water present in food is crucial for preservation. For example, drying or dehydrating food removes water, making it less hospitable for microorganisms to grow.

5. How does the chemical structure of water interact with biological tissue in food?

The chemical structure of water allows it to form hydrogen bonds with other molecules, including those in biological tissue. This interaction can affect the structure and function of tissue, such as in the case of cooking meat, where water helps to denature proteins and make them more tender.

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