cloud dreamer wrote:
Radium wrote:
Hi:

I notice that many fruit emit foul odors when ripe. What chemicals are
responisble for this?

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
STEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE EEEEEEENK!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!

What causes those immeasureably-foul odors?


Could be Ethylene.

Extremely unlikely.

Quote from http://www.mindfully.org/Plastic/Ethylene-Gas.htm :

"A flammable, colorless, gas with a characteristic sweet odor"

The odor I perceive from over-ripened fruit is very foul. Ever try
smelling a papaya up close? How about a mango that is over-ripened?

http://edis.ifas.ufl.edu/CV206 quote:

"Ethylene is a colorless gas with a sweet odor."

So ethylene is most likely not the direct cause of the foul odor.

http://ucce.ucdavis.edu/datastore/de...rveynumber=267
quote:

"Ethylene enhances several processes associated with fruit ripening,
including development of odour-active aroma volatiles (especially
esters)."

Apparently ethylene induces and speeds up the ripening process --
including the processes in which foul ripe odors are produced -- but
does not directly cause the foul odor of over-ripe fruits. It has to be
something else. What is it?

From Wikipedia (http://en.wikipedia.org/wiki/Ripen):

"Stages of a plant's life are influenced by hormones. An important plant
hormone involved with ripening is the chemical ethylene, a gas created
by plants from the amino acid methionine. Ethylene causes increased
levels of certain enzymes in fruit, which include:

* Amylase, which breaks down starch to produce simple sugars, and
* Pectinase, which breaks down pectin, a substance that keeps fruit
hard.

Other enzymes break down the lime pigment chlorophyll, which is replaced
by blue, yellow, or red pigments."


This is how some people will ripen tomatoes....by placing a ripe apple
in a paper bag with the unripe tomato. The ethylene emitted by the apple
will ripen the tomato.

From this idea, I figured out how to keep my banana from going black in
a couple days after I buy them. Since they ripen each other (being in
such close proximity), I separate them when I get them home. They can
last a week or more. (More than enough time to consume them).

..