What are you using the Tart & Sour in? Fruit, Bakery? The Citric and Malic acids will help fruits pop and bring them to the front. I'm not certain what's in the Tart & Sour, but if it is CA and MA then you could do a 10% solution of both and add individually until the effect is acheived. If Tart & Sour is something completely different then you may need to find a different route for it.