View Single Post
  #1   Report Post  
Old 10-06-2007, 04:30 AM posted to sci.bio.food-science,sci.chem,rec.gardens.edible,sci.agriculture.fruit,sci.bio.botany
Radium Radium is offline
external usenet poster
 
First recorded activity by GardenBanter: Jun 2007
Posts: 48
Default Why do ripe fruits - especially when canned - smell bad?

Hi:

I notice that many fruits [excluding apples] emit foul odors when
ripe. What chemicals are responsible for this? I've done as much
research as I can on this but not gotten anywhere. This isn't a
homework assignment. I am asking these questions out of personal
interest.

I hate those odors. That why I like to eat apricots, peaches, and
similar fruits when they are sour, hard, and greenish. When sour,
hard, and greenish, most fruits smell pleasant. When they are too
ripe, they become excessively sweet, grossly-soft up and turn mucus-
yellow; this is when they start to stink.

What causes those immeasurably-foul odors?

It could not be putricine. Putricine smells like rotting flesh, which
is also a foul odor but totally different from that of ripe fruits. To
my nose, over-ripe fruits don't have a smell that even nearly
resembles rotting flesh. Both are equally bad odors, though.

Its also not ethylene - a chemical used to speed ripening. Ethylene
has a sweet pleasant smell to it. I have smelled it myself in a lab.
It's beautiful.

Butyric acid smells like stinky cheese [including Swiss], smelly feet,
sweaty shirts, dirty socks, neck-sweat, back sweat, filthy scalp and
unwashed hair. So it definitely isn't butyric acid. In fact, since
these foul odors occur after ripening [a process which uses up the
acids]; I doubt that any acid or acidic substance is responsible for
the foul odor of ripe fruits.

I notice the stink especially in canned fruits. Most fresh fruits
don't have as much of a strong stink even when ripe. However, canned
fruits [often dripping in syrup] have an unbearable stench to me.
Maybe it is something to do with the sugar? I don't know.

Why do canned ripe fruits stink more badly than fresh ripe fruits?

Also, it can't be ethanol. I like the smell of ethanol.

I've asked similar questions in science newsgroups, and they think I
have an olfactory perception disorder causing me to perceive odors
differently from other humans. I don't believe this at all.

I have tried tiresomely searching on google but there are no websites
that have an answer to my question.

Also, I've noticed that most ripe fruits do not have to be rotten in
order to give off the foul odors I sense. Simply being ripe causes the
odor.

Any assistance is greatly appreciated.

If this is out of your expertise would you please give me an idea of
who could answer my question?


Thanks,

Radium