pitch pine roof trusses

Hi all.
I have undertaken a massive project involving some tricky woodworking and would really appreciate some advice.

I am in the process of renovating a barn built in 1678. I have removed 4 big roof trusses and purlins. They have some beautiful joinery in them. They have loose mortice an tenon joints to one end and the purlins are almost 15 meters long with stunning scarf joints joining the lengths. I think they are made from pitch pine.
All the timbers have been coated in whitewash over the centuries.

I have begun cleaning them as gently as possible. Firstly a light scraping to remove the worst of the whitewash then a nylon bristle brush to remove as much of what is left along with the ingrained dirt and dust. I have then lightly sanded. This reveals the original wood but left whitewash deep in the grain. I have managed to remove most with a light coating of nitromors. (not sure if this should be done but seems to be working. I have then cleaned this off with wire wool.
My question is what would be the best finish to use to protect them whilst keeping them looking as natural as possible. They will be going back in the kitchen area so will be subject to some moisture in the atmosphere.
I want to achieve a natural matt look to the finish.
Any help and advise would be much appreciated.
Pat