Moderators, I do apologize if this is too far OT to be acceptable; I'm hoping it's okay as a "using harvest/reducing waste" kind of post. But if not, please delete it.
It's the end of the gardening season, and no matter what some of my tomato vines seem to believe they can still accomplish, I know it's highly unlikely that fruit is going to get to be fully ripe and it's even more unlikely that the one---yes, ONE---tomato blossom I saw on Saturday is going to become pollinated and turn into a tomato of usable size and maturity; by now we're just not getting enough hours of sunlight.
So I've gathered up the green and greenish tomatoes and am having a go at making green tomato mincemeat. A friend of mine experienced at canning almost everything else is supervising the actual canning process to make sure I don't do anything foolish or counterproductive.
The recipe I have states emphatically: green, Green, GREEN, totally Green, tomatoes. There must be not so much as a hint of pink, white, yellow, orange or---of course!---red.
What I'm concerned about is, why?
Does this have to do with food processing/food safety issues? Or is it strictly an aesthetic concern, such as "once they start to go white or yellow or orange, you get segments and developing seeds and who needs seeds in the mincemeat?" Is it because they want really firm, firm fruit that won't turn to mush during the cooking (which is a while, I'll grant you)?