I have never heard of it either, was looking at our last 6 quarts of green beans last night and notice how they looked a little bah in color and thought back to when we would use baking soda to enhance the color of our vegetable's
we mainly use this when we had banquets for awards ceremonies knowing darn good well that there is going to be someone long winded and the plate timing would be off scheduling.
nothing like being served welted vegetable's.
this works great on broccoli, cauliflower, green beans, carrots, zucchini
this is what we would do...
you have remember we where using any where from a 5 to 10 gallon stock pots.
1. prep all the veggies.
2. in a pot of boiling water with a little butter <best you only do one type of veggie at a time> toss in the lets say broccoli in, and add 3-4 tablespoon of baking soda let it cook to just the point of being al dente.
you will notice that the color of the broccoli is now a deep green.
3. while it was cooking you would have a ice bath ready.
4. once it has hit al dente remove and drain and put immediately into the ice bath.
5. once chilled remove any ice left over, remove veggies from the bath and let drain again. and place in refrigerator/ walk-in.
too reheat...
in a stock pot, simmering with water and chicken broth add your veggies this will only take a few minute's, drain and place into a hotel pan with a little butter again.
now ready to serve after that wind bag has been talking for a extra 30 minute's.
now for doing this at the house would only use a pinch of baking soda.
as for the aftertaste never have noticed one, since any baking soda has been washed off, so any extra alkaline would be removed as well.
so if you did a quick blanch and wash and place in jars for canning would this work?
would have to figure on timing on the pressure as well.
sounds like nobody has ever tried, so guess I will have to try a couple jars this summer and will post a update on how it worked out...
and yes I do believe in safe canning.
will post a couple pictures of this with and with-out soon..