It depends on the design of the dryer, and how you use it.
With some assumptions, then the following is likely to be the case:
Assuming that the shelves are uniformly heated / cooled, and that you fully load shelves (loading more shelves for 140kg and less for 50kg) then for a completely filled shelf the drying time should be the same, providing that control rates for shelf heating / cooling are identical in the case of both loads, and that the condenser can trap all the moisture.
If you were to spread the 50kg across all shelves, then it will dry faster.