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Keep Bananas Fresh Longer (slices, too!)

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For many people, purchasing a bunch of bananas is the ultimate act of hope in the face of experience.

I'm no different. My thinking generally goes, "If I buy these now, I'm set on breakfast for a week." Then Thursday comes around, my 'nanners have turned brown, and suddenly Friday's looking like a toaster waffle sort of day. Sometimes I consider baking banana bread and pretending I meant to let them get overripe, but mostly I throw them away and feel bad.

There is another way. A better way. A way that requires nothing more than what is already likely to be in your kitchen.

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Optional science!

We're looking specifically at enzymatic browning and the effect of ethylene production here. If you want to dig much deeper, there's a ton of academic research on bananas available online.

"Relationship between browning and the activities of polyphenol oxidase and phenylalanine ammonia lyase in banana peel during low temperature storage" anyone?
(Postharvest Biology and Technology - PDF link)


When fruits or vegetables are peeled or cut, enzymes contained in the plant cells are released. In the presence of oxygen from the air, the enzyme phenolase catalyses one step in the biochemical conversion of plant phenolic compounds to form brown pigments known as melanins. This reaction, called enzymatic browning, occurs readily at warm temperatures when the pH is between 5.0 and 7.0.
(Australian Institute of Food Science and Technology - PDF link.)


Ethylene promotes maturation and abscission of fruits. This has been known since early last century. Since 1934, it is known that plants themselves can produce ethylene. Many climacteric fruits such as apple, banana and tomato show a strong increase in ethylene levels at the late green or breaker stage. As a consequence of high ethylene chlorophyll is degraded and other pigments are being produced. This results in the typical color of the mature fruit peel. Activity of many maturation-related enzymes increases. Starch, organic acids and in some cases, such as avocado lipids, are mobilized and converted to sugars. Pectins, the main component of the middle lamella are degraded. The fruit softens. These metabolic activities are accompanied by a high respiration rate and consequently by high oxygen consumption. Ethylene levels are especially high in the separating tissues resulting in abscission of the fruit.
(Margret Sauter, University of Hamburg.)
 
 
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rpb1 year ago
This article seems to assume that all of the ethylene either comes out of the stalk to be absorbed by the banana, or enters in via the stalk. Isn't the ethylene generated by the banana itself, all over? How does wrapping up just the stalk affect anything?

I tried it to see if it would make any difference, and it was a resounding failure. I kept two bananas on my desk, about 9-12 inches apart (I briefly moved them closer for each photograph), one with stalk wrapped tightly with clingfilm (see fifth close-up photo) and one without. By the fourth day I don't think there is any significant difference between the two (or, in fact, on days 1, 2 or 3)!

I'm going to eat them now!
day1.jpgday2.jpgday3.jpgday4.jpgwrappings.jpg
wilgubeast (author)  rpb6 months ago
Sorry for performing necromancy on this thread, but this bears stating: Ever since you tested and confirmed that wrapping the stem has no effect, I've wondered how I ever came to that conclusion. Well, I finally figured it out! I made an incorrect leap of imagination about ethylene production and abscission, the natural splitting of leaf or fruit from stem.

I re-read the Sauter paper and realized that I got a little too inferency. I thought that since ethylene caused abscission, it would make sense to cover the point prone to abscission. I didn't test when I saw confirmations from Lifehacker and eHow. (I know! Those were my sources after all the research I'd done?! I'm embarrassed for me, too.)

Thanks for eating bananas for science!
babybayrs rpb1 year ago
These two bananas look like twins!
rpb babybayrs1 year ago
I think most bananas *are* "twins", in a sense, aren't they? Since the plants are all propagated by cloning another plant, and the fruit are unfertilised:

http://en.wikipedia.org/wiki/Bananas#Modern_cultivation

Maybe 'twins' isn't quite the right word but they all come from a relatively small number of "mothers" that have been cloned millions of times. This is probably why most bananas look very similar, unlike, say, apples.

8-)
babybayrs rpb1 year ago
Although they were treated differently, they looked the same, like twins to me. Good selection of experiment samples.
rpb rpb1 year ago
Note that I should point out the photos above are in order on Day 1 (purchase day), Day 2, Day 3 and Day 4. I kept them separated by 9-12, apart from during their photoshoots, in case the ethylene from one banana affected the other.
antioch rpb1 year ago
Hrm, great experimenting and documentation. And of course interesting result...
ahbugmenot9 months ago
So I tried it with a lot of bananas, and it simply did NOT work. See my results here: http://imgur.com/gallery/j8lRC

I'd like to have experience returns of people for who that worked.
@OP: did you try it before posting it?
wilgubeast (author)  ahbugmenot9 months ago
From your results, it looks like separating the bananas followed by wrapping has no discernible visual effect. You busted my myth!

I tested separation but NOT wrapping. That was a bit of leap to synthesize the research around off-gassing and anecdotal reports that wrapping the stems made a difference. Clearly, it makes no aesthetic difference. (You mind if I incorporate your photos to make this ible more accurate?)

sbrown95781 month ago

I always had this problem and then one day I read that if you just cut off the stalk as low to the banana as possible without exposing the banana that the bananas would last much longer. This is what I did. Now I have bananas that last through the week and then some.

wilgubeast (author)  sbrown95781 month ago
If you're inclined to buy too many bananas (no such thing!) and want to take a shot at winning the Scientific Method Contest that's running right now, documenting what actually happens over time with each freshness preservation method would probably vault you pretty high into the standings.
sjpapmom5 months ago
To keep banana slices fresh
Dip in agave and freeze
squishyjoss5 months ago
Its magnificent :)
ecoben6 months ago
I must try this out to verify. thanks!
This is great! I have been struggling with my bananas for a long time. Now I know know what to do with them!! I have to have calcium and I eat them day and night!
hilarysettle7 months ago
Ok, this makes sense, I just bought a bunch and I'm going to try separating them. Like lucylouwho, I've been struggling too with my bananas, so funny.
lucylouwho8 months ago
This is great! I have been struggling with my bananas for a long time. Now I know know what to do with them!! I have to have calcium and I eat them day and night!
ahbugmenot9 months ago
@wilgubeast:
Thank you for your answer. I didn't think to compare separated bananas with bananas still attached. I'll try it the next time and see what are the results.

No, I don't mind at all, you can use my pictures if you want.

(Sorry, I cannot reply directly to your comment, the Captcha doesn't load when I try to reply on a thread...)
wilgubeast (author)  ahbugmenot9 months ago
You're awesome.

(And try clearing your cache or turning off adblock or using Firefox to make the Captcha load correctly.)
vishalapr10 months ago
Yummmm...., I'm just eating the bananas I kept fresh with these techniques, Thanks for the instructions!
Yardster1 year ago
I tried this in a fashion. I happened to have melted wax in the kitchen for another project and dipped the stem ends. I didn't see any appreciable difference in aging, but I'll have to try it again sometime with more controls.
wilgubeast (author)  Yardster1 year ago
I'm very interested in seeing whether this method is replicable for more people. Let us know how your experiments go. So far the only clear winner for banana freshness preservation is separating them from the bunch.
babybayrs1 year ago
Didn't read all 90 comments. Ignore this if it's already mentioned. Carbon dioxide is an inhibitor of ethylene production. To ensure longevity of bananas, put them in an airtight container connected to pressured carbon dioxide tank with flow control valve at the bottom of the container and a hole on top of the container to let go of ethylene. The only question is: can we afford it?
I wondered if banana stems dipped in hot candle wax would work. No air gaps.
Superb instructable wilgubeast! Thanks for doing the science on preserving bananas for a longer time. I had no idea what factors were involved. 10/10+
Who would have thought this would make a difference! I love bananas, brilliant for a snack on the go and they come in their own protective case. I am interested how much longer the bananas last?

I will definitely be trying this.
kbeard31 year ago
Great idea- and thanks for the science! I tried it and it really does work.
Romi871 year ago
Thank you
Nyxius1 year ago
ethylene gas is also heaver than air so keeping them off surfaces helps.
wilgubeast (author)  Nyxius1 year ago
That is super useful! Be sure to keep your bananas lifted, people.
No, not those bananas... The real ones...lol
Thank you. Instead of lemon juice, orange juice does the job being not as acid.
batkinson11 year ago
lt.greg... "I'm Chiquita banana and I've come to say - Bananas have to ripen in a certain way- When they are fleck'd with brown and have a golden hue - Bananas taste the best and are best for you - You can put them in a salad - You can put them in a pie-aye - Any way you want to eat them - It's impossible to beat them - But, bananas like the climate of the very, very tropical equator - So you should never put bananas in the refrigerator."
-chiquita.com
lol
Well "Chiki" - I guess I must have a magic refrigerator then - because when I put green bananas in there - they last three times as long as the ones from the same batch that I leave out on the counter. Yes - if you leave them in TOO LONG and don
tr check them every few days they turn brown. But they DO definitely last longer for me, in my fridge.
Greg
:-)P
Listened to a review about a book written about the history of the modern banana not to long ago. Turns out that the old Chiquita banana jingle was intended to mislead you so that the fruit would go bad faster and you would have to buy more often. Good old capitalism and marketing at work.
wilgubeast (author)  marshall77071 year ago
Got a link for us? Bananas are fascinating. As is manipulation through marketing. And jingles! All together? Better and more incendiary than Bananas Foster.
http://www.npr.org/2011/08/30/139787380/bananas-the-uncertain-future-of-a-favorite-fruit

I think I heard the same interview, which was a rebroadcast of this one. The take away: bananas are shipped in refrigerated trucks and stored in grocery store coolers until put out on display.
Except when they are fully ripe; i.e. are fully yellow and covered in brown spots, then they are fine to put in the fridge.
thanks! I m going to try this, I really don't like the bananas too ripe.
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