That is one "trick" that translates from real life. I remember Mom always added a squeeze of fresh lemon to the blueberries as she cooked them down for pie or cobbler filling. It wasn't enough to add a perceivable sour or lemon flavor; but it would brighten the berries and help them stand out. For my palate at least, a bit of lemon concentrate seems to do the same/similar thing with most berry concentrates (I haven't tried it with strawberry; but I have had success with black, boysen, blue, and even raspberry), in e-liquids.
Of course, this is nothing new, or original thinking on my part. Other DIYers have been using lemon in this manner long before me. It is just one more thing I read, thought to myself "oh, yeah, that could work," and happily plagiarized for my own use. I get zero credit for originality.
I think you are right, @FranC. If, your objection to lemon is flavor (vs. inability to taste it), then it may work as a berry brightener for you. If you can't taste lemon at all... then I am have no idea if it will be any help.
