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Old 21-05-2006, 03:34 PM posted to sci.bio.food-science,sci.chem,rec.gardens.edible
cloud dreamer
 
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Default Why Do Ripe Fruits Smell Bad?

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.

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).

..