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Old 10-06-2007, 06:26 PM posted to sci.bio.food-science,sci.chem,rec.gardens.edible,sci.agriculture.fruit,sci.bio.botany
Omelet Omelet is offline
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First recorded activity by GardenBanter: Nov 2006
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Default Why do ripe fruits - especially when canned - smell bad?

In article .com,
Bill Penrose wrote:

On Jun 10, 8:46 am, Radium wrote:
...In addition, the answer is nothing close
to what "Bill Penrose" [the goofball] claimed.


You mean you *know* the answer? Then why the question?

When fruits ripen, one of several mechanisms of autolysis set in.
Enzymes are cut loose that begin the breaking down process of the
fruit. In most berries, the 'purpose' is to attract birds or other
animals that will eat the berries and distribute the seeds. Many
fruits work this way, too. Bananas are a good example. They don't turn
black because of bacteria or mold, but because enzymes start breaking
down the fruit from inside.

Only later do bacteria, molds, and yeasts get in the picture. Some
berries become so fermented that birds have been observed to get
drunk.

The products of autolysis include alcohols and esters, but they're
different for every kind of fruit, depending on the enzymes present.

Now what happens in canning? The enzymes would be killed by the heat,
so any breakdown would have to be nonenzymatic, ie, esters decomposing
to alcohols and acids, etc. Sulfur compounds to smaller and more
volatile sulfur compounds, etc.

By the way, my mother once worked in a fruit packing plant. She would
never eat canned fruits or vegetables again because of the practices
she saw there.

Okay, there's your answer. It is also true that food companies go to
some lengths to prevent these processes, so don't rule out the brain
tumor hypothesis either.

DB


A nice scientific explanation. If that does not satisfy him, nothing
will. Well done!

Now, care to expound on the fruit canning practices that turned your mom
off? I'm intrigued!
--
Peace, Om

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"My mother never saw the irony in calling me a Son of a bitch" -- Jack Nicholson