Ok I don't know if any of this will help. At the base camp in the future, my sim cannot program new recipes or improve the meal quality of the two synthesizers. However, if she goes to her future home (which I built for cheap), the synthesizer there shows both options.
She could improve the meal quality level 1,2, or 3.
For Program New Recipe - there were five (I think, I'd programmed a couple already which had gone into the Serve Dessert section).
Synthesized Fruiti Bobs (Found in Breakfast Menus)
Synthesized Nutrition Cube (Found in Dinner Menus)
Synthesized Statuesque Surprise (Found in Dinner Menus)
Synthesized Sphere of Destiny (found in Serve Dessert)
Synthesized Chocolate Mini Gnome (found in Serve Dessert)
The Gnome and the Sphere both fill her hunger need from red to the top.
The Food Synthesizer at her future home appears to have recipes my sim doesn't know yet too, such as firecracker shrimp etc.
(Also noticed - not a synthesizer issue but the fridge in her future home no longer holds the leftovers that were there before she went back to the present. Now she has returned to the future they're gone).
The Food Synthesizer 20+ moodlet does not get any higher/better with a Synthesizer upgraded to level 3.