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How much pectin do tomatoes have?

Posted by malna NJ 5/6 (My Page) on
Tue, Aug 21, 12 at 5:40

I made some peach salsa over the weekend - basically Annie's recipe subbing 1/2 peaches for 1/2 of the tomatoes. I used orange varieties for the tomatoes. I wanted it very orange, so I didn't add any sauce or tomato paste.

After I drained the tomatoes, I noticed the juice collected was really thick - almost as if I had added pectin to it.

It was suitably thin when I put it in the jars for processing but the next morning after it cooled, the salsa was really thick. Think it might have been the particular variety of tomato? (I used Kellogg's Breakfast and Angora Orange.) I can't believe it was the peaches. I never get peach jam to set without pectin LOL.

Wish I could figure it out, because the salsa came out the perfect consistency. Or maybe the canning gods were just being kind to me that day :-)


Follow-Up Postings:

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RE: How much pectin do tomatoes have?

Interesting article on it linked below. If I understand it correctly the pectin in your peaches kept the natural pectin (PME) in the tomatoes from being destroyed by the heat thereby allowing it to contribute to the gelling process.

tomatoes have another enzyme as well, a polygalacturonase (PG), which causes some trouble. If I got it right this enzyme degrades the pectin gel (and plays an important role in the ripening of tomatoes). One therefore needs to inactivate the tomato PG enzyme and this is done by heat. Regrettably this also knocks out the PME of tomato, but this is were the carrots and oranges come in � they have PME, but no PG. Hence they hold the key to unlock the gelling properties of tomato. So to sum it up, you can use enzymes present in carrot and orange juice to chemically change the pectin of tomatoes to make it more prone to gelling in the presence of calcium ions.

So tomatoes alone? No, any natural pecticn they have would be destroyed by the PG and heat. The yellow tomatoes would likely (just a guess) less PG since it is tied to the color of ripening. But when mixed with other things that have no PG (like carrots, oranges and perhaps peaches) it isn't destroyed.

If correct then theoretically if the peach-tomato salsa was made with red tomatoes the effect wouldn't be as great.

Dave

Here is a link that might be useful: Tomato gels with natural pectin


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RE: How much pectin do tomatoes have?

  • Posted by malna NJ 5/6 (My Page) on
    Tue, Aug 21, 12 at 18:06

Fascinating article, thank you!


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RE: How much pectin do tomatoes have?

huh. I didn't know you could alter Annie's salsa to include peaches. I would have thought that it wouldn't be safe, as I thought peaches were low acid....


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RE: How much pectin do tomatoes have?

Peaches like most all fruits with a few exceptions are high acid.

Dave


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RE: How much pectin do tomatoes have?

Ah! I didn't realize that! (clearly...). Good to know!!


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