Having posted the first response, I will admit I did misunderstand the question. I was thinking of the white pith which surrounds the entire fruit, not the transparent membrane which surrounds each section. Having said this, I have no idea how they remove the membrane.
Mr Thin Skin
It seems I am now trying to picture a machine capable of skinning, de-veining and sizing shrimp. For true? Saw with your own eyes? Was it in use at the time? Was it bigger than a refridgerator? Where did you see this wonderous invention?
Actually the shrimp machine isn’t that amazing. I’ve seen a small version for the home that is just a tool, not a machine. The home version works like this. You break the head off by hand (a simple task easily replicated by some big conveyor machine). The shrimp is the forced through the tool severed head end first. The tool looks like a tupperware bowl with a lid on it. In the lid there is a series of holes of varying sizes. You match the shrimp with the hole that is most close to the shrimps diameter. The hole is the trick part. It has a raised lip that is sharpened all the way around. In the hole there is a sharp little barb that sticks out. You line up the vein with the barb and force the critter through the hole, the sharp egde skins the fucker and as it passes into the hole the barb drags out the vein. Then it falls into the tuperware skinned and veined. I assume there is a big automated machine that does this by the million, but the task doesn’t seem too daunting.
I am stunned that the teeming millions are silent on this, surely somewhere is a person with the Straight Dope.
Desperate times call for desperate measures, it’s just a suggestions you understand…
Let’s wake Cecil !
I’ll poke him with the stick, you make a loud noise…
It started as just a nagging question but the silence of the teeming millions is making me suspect something else is at work. A review of this thread makes it clear that y’all understand the question clearly now (sorry for the confusion, my lack of language to blame ). And yet, still we are no closer to an answer. I still want to know. How do they do this? Perhaps we should consult the science advisory board. Though it seems more a process than a science.
It could be done by hand, (witness the production of saffron) but surely they would be much more expensive. I know you all promised to get a tin and look into it. Any ideas yet? As you may have guessed this is really bothering me.
- It can’t be chemicals as this would also damage the membrane around the individual segments.
- I assume as someone else mentioned that it is to do with heating, in the same way that tinned tomatoes are made. Blanche the fruit for a few seconds and any skin falls off.
Unfortunately it turns out that while they are blanched to loosen the membrane, what ultimately frees the individual segments from its “skin” is a chemical process, specifically they are dumped into a lye bath which “eats” the membrane leaving the segments behind.
Cite.
Aah, 1999.
I imagine it gets done like this, only by some machine.
Let me blow your mind.
Back in 1999, it would be like posting to a thread started in 1986. :eek:
No it wouldn’t. Internet-time is non-linear.
This is true. It’s to do with the tubes.
I’m just amazed that nobody back in 1999 could comprehend what the OP was talking about with the membranes. It’s insane.
I enjoyed the many references to Ask.com. Remember when there was no Google (at least that anyone used)?
Chemical engineer here with limited exposure to food processing. The membrane you are talking about is usually removed by lye peeling. The fruit is immersed in boiling caustic (2-5%) for about 30 seconds. The caustic removes the pectin that holds the membrane together. It is then washed to remove any excess caustic and the membranes get removed too since they are no longer attached.
Tomatoes are peeled the same way too.
The pectin is usually recovered for use in jellies and stuff.
Here is a filipino website that provides the recipe to do this at home :
Interesting. I cut the membranes away with a knife for salads. I don’t think I could do very well on something a small as Mandarin oranges.
Y’ever have an idea for a thread while you’re away from the computer and then completely forget to post it? This is one of those nagging little questions I plan to post at least 3 times a week when I’m packing my daughter’s lunch. I’m so relived that we finally got an answer! 