Hi,
I think you can do this with disallowed combinations. The simplest way is using the Disallowed Combinations Filter.
I set up a design with a categorical factor for ingredient (A, B, C) and a continuous factor for Amount (0 to 2).
Then I set up 2 disallowed combinations, as below. (I select OR after creating the first one)
For B, amounts between 1 and 2 are disallowed.
For C, amounts between 0 and 0.5 are disallowed.
You should find that the resulting design (attached) obeys these constraints.
You can also use Disallowed Combinations Script to do the same things.
These are the same disallowed combinations defined in a script:
X1 == "B" & (X2 >= 1 & X2 <= 2) | X1 == "C" & (X2 >= 0 & X2 <= 0.5)