If the applesauce doesn't work, another thought would be Standlees timothy pellets and add some water.
I mix my IR horse's supplements in one or two 8 ounce cups of straight timothy pellets. Orchard grass pellets are also ok to use.
I buy Standlee brand at Tractor Supply. I have been using their brand for several years and like them because they are never dusty, and I have only found a small piece of hay twine once or twice in all those years.
If you are dealing with true powder as opposed to something granulated like sugar is, the last resort would be to make a 50-50 mix of water and pure apple juice.
Buy a 60 CC syringe, cut the tip off, use your finger to block the bottom, put the powder in, add the water/apple juice, shake or mix well with a cocktail stir, then syringe it down like you would paste wormer meds
I have to do that with my IR horse's prescription meds, lol He will not eat the meds in his feed pan but is happy to slurp the stuff down if I mix with water & apple juice in a syringe. I've been doing that twice daily since 2012 ----- pretty soon I will be at 3,000 loyal and loving times of making sure that horse gets his insulin meds ---- we need a passing out emoticon