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I can't stand the pith on citrus fruit. Canned mandarin oranges seem to have their segments magically removed from the outer membrane that surrounds it. I know how to supreme a citrus fruit, and that is what I do when I want to eat one, but the canned ones don't seem to have been cut.

Does anyone know if there is a process that accomplishes this, that can be done in a home kitchen?

Debbie M.
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  • peel them with rubber-gloves on? – Thorst Dec 30 '15 at 06:56
  • Suggestion: Try clementines, a loose-skinned citrus fruit of roughly the same size that peels very easily. (I can usually peel grapefruit well enough for my tastes, but it takes a while.) – keshlam Dec 30 '15 at 16:08

2 Answers2

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In theory, yes you can. Whether you want to is a completely different question.

    • The segments are "peeled" by soaking them in hydrochlorid acid. Which sounds worse than it is, because the concentration is somewhere between 1% and 0.3% (sources vary). (1)
    • Once the outer skin is dissolved, the acid is neutralized by dumping them in a lye bath (sodium hydroxide).
    • Finally a good long soak in plain water to get rid of whatever might still cling to the fruit and then it's off to the canner.

  2. Other sources claim that the segments are simply peeled by soaking in a lye bath and then rinsed. (2)

  3. A third source quotes a Dutch magazine and claims it's lye first and hydrochloric acid later. (3)

Note that hydrochloric acid and sodium hydroxide form NaCl and H2O or, plainly put, salt water if the ratios are correct. So apparently the whole process is quite harmless for us consumers.

Sources:
(1) German Wikipedia; Die Zeit (both in German)
(2) English Wikipedia
(3) nyceyenne (also in German)

rackandboneman
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Stephie
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    Note to self: never eat canned fruit again. – Todd Wilcox Dec 29 '15 at 15:55
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    @ToddWilcox Then you may never want to eat the cherry on top of your cake. They are washed with bleach until they become white and then colored again with artificial food coloring. In between, they do all the processing to crystalize them. Quite disgusting. Still, I eat them first! – Ismael Miguel Dec 29 '15 at 17:03
  • @IsmaelMiguel I don't think there's ever been a cherry on a cake I've been served - but I don't like fruit flavored confections anyway. Just don't tell me how chocolate is processed! – Todd Wilcox Dec 29 '15 at 17:19
  • @ToddWilcox I won't, I won't. I don't even remember how it was done. – Ismael Miguel Dec 29 '15 at 17:27
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    I bet that "good long soak in plain water" explains where the flavor of canned mandarins goes. – Wayfaring Stranger Dec 29 '15 at 19:14
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    @WayfaringStranger The juice vesicle cells are still intact so soaking in water should mostly only cause a little more water to move into the fruit by osmosis. – David Richerby Dec 30 '15 at 14:53
  • @DavidRicherby Plasmodesmata https://en.wikipedia.org/wiki/Plasmodesma , to say nothing of how the skin is attached to the individual segments. You beat up a fruit and it gets leaky. – Wayfaring Stranger Dec 30 '15 at 15:17
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    I can provide a direct link to that Dutch source: http://keuringsdienstvanwaarde.kro.nl/seizoenen/2009/30-39031-08-01-2009/290-90947-hoe-worden-mandarijnen-in-de-fabriek-gepeld "How are mandarins peeled"? – MSalters Dec 30 '15 at 15:40
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This is fairly easy, and completely safe, to do with pectinex enzyme. ...and yes, you want to! It is how modernist chefs remove the pith from citrus. You can order Pectinex Ultra-SPL from Modernist Pantry (modernistpantry.com). See this link for the science and technique.

moscafj
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    That link uses both Pectinex Ultra-SPL and Pectinex Smash XXL; the former is available as you say but the latter is not. Do you actually need both, or will it work with just the one? – Cascabel Dec 29 '15 at 15:45
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    @Jefromi I have a copy of Dave Arnold's book (http://www.amazon.com/Liquid-Intelligence-Science-Perfect-Cocktail/dp/0393089037/) and in it he describes using only Pectinex Ultra-SPL. Way at the end of the linked article, he also notes that "Peelzym and Pectinex SP-L are probably slightly different mixes of the same components." Peelzym is referred to as the original enzyme which is no longer available. Seems likely that Ultra-SPL on its own should work fine. – logophobe Dec 29 '15 at 15:59
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    Pectinex Ultra-SPL alone works just fine. I have used it many times. In fact, you don't need the heat step (it speeds the process, but is not necessary). Just place in fridge overnight. Carefully rinse the next day. – moscafj Dec 29 '15 at 17:33