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  #1  
Old 04-06-2004, 03:54 PM
lissener lissener is offline
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Why does fish taste fishy?

What is that taste, and that smell, that's very specific to fish? The smell that's not so bad when the fish is fresh, but can get way the hell nasty when it's old? The taste that, say, mackerel has more of than, say tuna; that salmon has more of than halibut?

What's the chemical compound that smells the same from fish to fish to fish, but is not really evident in any other animals?
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  #2  
Old 04-06-2004, 07:21 PM
donkeyoatey donkeyoatey is offline
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The compound is trimethylamine .

Quote:
....trimethylamine, a byproduct of protein digestion released by bacteria living in the gut. This small molecule—the compound that gives fish their fishy odor—smells foul or garbagelike at low concentrations and fishy in larger amounts.
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  #3  
Old 04-07-2004, 09:17 AM
lissener lissener is offline
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Quote:
Originally Posted by donkeyoatey
The compound is trimethylamine .
Hmm. What about the non-bacterial smell? before it's rotted? What about the "fishy" taste of fresh mackerel?
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  #4  
Old 04-07-2004, 12:07 PM
Bippy the Beardless Bippy the Beardless is offline
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I susspect their is a subjective level in what people think of as a fishy taste which will confuse things.
Personally I wouldn't call Smoked Samon a Fishy taste, but I know others that call it a very fishy taste. That out of the way...
I find seaweed to have what I would call a fishy taste, I believe that it may be the iodine in the seaweed that gives the fishy taste.
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  #5  
Old 04-07-2004, 12:25 PM
Duke Duke is offline
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Oh, fer cryin' out loud, I just got done reading this thread. I don't think I'm every going to be able to eat fish again.
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  #6  
Old 04-07-2004, 12:29 PM
Squink Squink is offline
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Fish contain a high proportion of unsaturated fatty acids (Omega 3 and the like). These go rancid (oxidize) pretty fast in air, which contributes to the fishy taste. Gut bacteria from the fish also produce fishy tasting byproducts, and the trimethyleamine donkeyoatey mentioned comes from the larger monamines which are prevalent in fish flesh, many of which also taste or smell fishy.
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  #7  
Old 04-07-2004, 01:41 PM
lissener lissener is offline
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Quote:
Originally Posted by Squink
Fish contain a high proportion of unsaturated fatty acids (Omega 3 and the like). These go rancid (oxidize) pretty fast in air, which contributes to the fishy taste. Gut bacteria from the fish also produce fishy tasting byproducts, and the trimethyleamine donkeyoatey mentioned comes from the larger monamines which are prevalent in fish flesh, many of which also taste or smell fishy.
is it the monamines then that give fish its unique flavor? I'm talking about fresh fish, not about bacterial activity. The "fishy" taste tha oilier fish have; what is it that's oil soluble that fish have but other animals don't? is it the monamines?
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  #8  
Old 04-07-2004, 02:12 PM
theR theR is offline
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I have never eaten fresh fish that tasted fishy and it usually doesn't smell that way to me, either. A "fishy" taste is generally a sign of fish that is not fresh, in my experience.

In fact, I often wonder if some of the people that don't like fish have ever actually eaten fresh fish or have only eaten the crap that is frozen, old, or just poor quality. If that is all I ever had, I wouldn't like it either.
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  #9  
Old 04-07-2004, 02:55 PM
Bippy the Beardless Bippy the Beardless is offline
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I susspect some may never have eaten fish that was going off, and so use the word fishy to discribe the taste of fresh fish. Certainly the fish that I would catch with the help of my Grandad and cook and eat on the same day tasted very fishy to me.
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  #10  
Old 04-07-2004, 03:15 PM
lissener lissener is offline
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Quote:
Originally Posted by theR
I have never eaten fresh fish that tasted fishy and it usually doesn't smell that way to me, either. A "fishy" taste is generally a sign of fish that is not fresh, in my experience.

In fact, I often wonder if some of the people that don't like fish have ever actually eaten fresh fish or have only eaten the crap that is frozen, old, or just poor quality. If that is all I ever had, I wouldn't like it either.
That's why I so carefully defined it, R. I live in Seattle, so I've eaten plenty of fresh fish. The "fishy" you're thinking of is not the "fishy" I mean. Surely you'll agree that some fish taste "fishier" than other fish? Even when fresh? That's the "fishy" I mean.
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  #11  
Old 04-07-2004, 03:25 PM
Squink Squink is offline
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Quote:
Originally Posted by lissener
That's why I so carefully defined it, R. I live in Seattle, so I've eaten plenty of fresh fish. The "fishy" you're thinking of is not the "fishy" I mean. Surely you'll agree that some fish taste "fishier" than other fish? Even when fresh? That's the "fishy" I mean.
That's my problem with your question. Living in the center of the continent, it's hard to figure if my perception of "fishy taste" is the same as yours. I do know that the oilier fish can devlop an odd taste within hours, but the relative contribution of all the different chemicals involved remains a mystery to me.
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  #12  
Old 04-07-2004, 03:36 PM
Squink Squink is offline
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Quote:
Originally Posted by lissener
That's why I so carefully defined it, R. I live in Seattle, so I've eaten plenty of fresh fish. The "fishy" you're thinking of is not the "fishy" I mean. Surely you'll agree that some fish taste "fishier" than other fish? Even when fresh? That's the "fishy" I mean.
That's my problem with your question. Living in the center of the continent, it's hard to figure if my perception of "fishy taste" is the same as yours. I do know that the oilier fish can devlop an odd taste within hours, but the relative contribution of all the different chemicals involved remains a mystery to me.
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  #13  
Old 04-07-2004, 04:46 PM
lissener lissener is offline
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OK, try this.

You're on a boat, in the Caribbean. You're fishing. You pull a fish out of the water. Immediately, you clean it and filet it. You raise the fillet, still quiveringly fresh, to your nose, and sniff. Mmm. Fresh fish.

A very distinctive smell, even when subtle. Beef doesn't smell like that, neither does pork or poultry or anything else: only fish has that distinct smell--don't even call it fishy--that nothing else has.

Ditto, eating fish, even the freshest twitching sashimi: fish tastes like fish, not like chicken.

Why? what's that unique taste/smell, common to ALL fish, found in varying degrees of concentration in different fish, and found in no other meat.

Is that monoamines? or is it something else? or does anyone know?
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  #14  
Old 04-07-2004, 04:55 PM
Loopydude Loopydude is offline
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Y'know: A lot of sushi and sashimi I eat, now that I think about it, seems to be conspicuously lacking in that stank fishy odor. However, when I buy a hunk of salmon or tuna at the market, it's cold, raw, and reeks of fish. It can't be that my senses are dulled by massive doses of wasabi, becase sometimes I just eat it plain, and I smell it on its way up to my mouth. I like big chunks of sashimi, so there's enough fish there to stink if it had any fishy odor.

How is this possible? I'm sure they don't use special stink-free fishes in Japanese restaurants. It must have to do with preparation. Does this mean the fishy smell is somehow not intrinsic to the tissue, but is a residue that does or does not form at some stage in preparation? Or does preparation of sashimi somehow mask or remove the smell?
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  #15  
Old 04-07-2004, 06:27 PM
lissener lissener is offline
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Quote:
Originally Posted by Loopydude
Y'know: A lot of sushi and sashimi I eat, now that I think about it, seems to be conspicuously lacking in that stank fishy odor. However, when I buy a hunk of salmon or tuna at the market, it's cold, raw, and reeks of fish. It can't be that my senses are dulled by massive doses of wasabi, becase sometimes I just eat it plain, and I smell it on its way up to my mouth. I like big chunks of sashimi, so there's enough fish there to stink if it had any fishy odor.

How is this possible? I'm sure they don't use special stink-free fishes in Japanese restaurants. It must have to do with preparation. Does this mean the fishy smell is somehow not intrinsic to the tissue, but is a residue that does or does not form at some stage in preparation? Or does preparation of sashimi somehow mask or remove the smell?
The protective slime coat that most fish have can smell strongly of fish, even when they're fresh--even when they're alive. THAT's the smell I'm talking about: that clean, fresh-fish smell. Why is that unique to fish?
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  #16  
Old 04-07-2004, 08:53 PM
Loopydude Loopydude is offline
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You know, you're right. I used to love to go fishing as a kid, and if I caught anything, I came home stinking like a fish, even if I threw them all back because they were too small or chubs or whatever.

When I get a salmon fillet or steak at the market, it's got the skin still on it. It must the the skin that makes it stinky; whereas sashimi is washed, I'm sure, and there better not be any skin on the salmon!

But then again, tuna! Stinks like...well, tuna! Open the can: No skin, just stinky fish. Is that a different kind of fish stink, though?
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  #17  
Old 04-07-2004, 09:54 PM
precipitate precipitate is offline
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Quote:
Originally Posted by Loopydude
How is this possible? I'm sure they don't use special stink-free fishes in Japanese restaurants. It must have to do with preparation. Does this mean the fishy smell is somehow not intrinsic to the tissue, but is a residue that does or does not form at some stage in preparation? Or does preparation of sashimi somehow mask or remove the smell?
The fish you get in any reputable sushi restaurant is much, much fresher than the stuff in your grocer's seafood case. It's the freshness rather than the preparation that makes the difference. If you've got a good fishmonger near you (well, and you're near a coast or a major metropolitan area), the hunk of tuna you buy should smell much less fishy than the stuff you get at the grocery store.
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  #18  
Old 04-07-2004, 11:30 PM
Trigonal Planar Trigonal Planar is offline
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I figured someone would bring this up sooner or later. I don't eat a lot of fish, but I do thoroughly enjoy fish and eat it whenever I can. Typically I've heard the "complaint" about fish tasting "fishy" from people who don't like fish. I, personally, don't really like meat. Would it be valid for me to ask why meat tastes "meaty"?
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  #19  
Old 04-08-2004, 12:04 AM
Squink Squink is offline
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Quote:
Originally Posted by Trigonal Planar
I, personally, don't really like meat.
Have you tried rubbing it in oxidized fish mucus? That could change your opinion.
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  #20  
Old 04-08-2004, 12:28 AM
glass glass is offline
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[QUOTE=Trigonal Planar]I figured someone would bring this up sooner or later. I don't eat a lot of fish, but I do thoroughly enjoy fish and eat it whenever I can. Typically I've heard the "complaint" about fish tasting "fishy" from people who don't like fish. I, personally, don't really like meat. Would it be valid for me to ask why meat tastes "meaty"?[/QUOTE

Sure.....as long as you don't dislike the smell of fish and you eat liver
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  #21  
Old 04-08-2004, 10:40 AM
Bippy the Beardless Bippy the Beardless is offline
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Quote:
Originally Posted by Trigonal Planar
I figured someone would bring this up sooner or later. I don't eat a lot of fish, but I do thoroughly enjoy fish and eat it whenever I can. Typically I've heard the "complaint" about fish tasting "fishy" from people who don't like fish. I, personally, don't really like meat. Would it be valid for me to ask why meat tastes "meaty"?
It would be valid to ask why meat tastes meaty, if you are talking about the red meats it has something to do with the blood, since the 'juice' that comes out of the meat during cooking is very meaty in taste. But then again there is the fact that meat stock needs bones in the preparation to be good, but this may be due to the gelatin and similar in the bones that gives stock a good consistency.
If you are realy interested why meat tastes meaty, please open a GQ thread on the subject, I'm sure Mangetout would be able to help answer that question better than I.
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  #22  
Old 04-09-2004, 12:44 AM
Bob55 Bob55 is offline
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Quote:
Originally Posted by donkeyoatey
The compound is trimethylamine .

AAAHHHH!!! I use this in my lab sometimes (for protein crystallizations), I was extremely upset one day when I actually got crystals in it, which meant I would be using it more frequently. The stuff is horrible - so bad that I'll wear double gloves before even touching the bottle, and throw them away immediatly.

Spermidine is another chemical I use with an interesting smell, but I won't go into what it smells like
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  #23  
Old 04-09-2004, 02:26 AM
umop ap!sdn umop ap!sdn is offline
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I was under the impression that phosphine was the compound responsible for "fishy" smells, and that trimethylamine has more of a prawn smell. Got this out of a book (Merck Index?) which I don't have with me and can't cite.
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