The torches that chefs use are either propane or butane. So no, using a butane lighter would not alter the flavor of your food.
My only question would be if the lighter would hold enough butane to last long enough to do the job. And, the way mine is made I would probably be dragging my tumb nuckle through hot molten sugar.
Harbor Freight (hardware store) has a small butane torch for $8. You could probably find the "old school" big BernzOMatic propane torch for about $15 at most hardware stores.
"It ain't what you don't know that gets you in trouble. It's what you know for sure that just ain't so." - Mark Twain