All woods (I'm told there is one exception ) wil change color with time and exposure to UV. Supposedly, marine varnishes with UV inhibitors delay the process. But, the only delay.
There was once a woman who owned a lumber company and woodworkers supply. She was known as the Lumber Lady. She developed a finish that (she claimed) prevented color changes. Sadly she died soon after bringing this product to the market and the forumla was lost.
I suggest you just make the item and let nature takes it's way.
"Folks is funny critters."
Think for yourselves and let others enjoy the privilege to do so, too. ~Voltaire