Diastatic power is a measure of enzymes that convert starches to sugars. Malt extracts are created by mashing grains. Once the mash is complete, the enzymes are denatured during processing, so the extract has no diastatic power. I’ve never heard of using diastatic malt in pizza dough but pale malted barley, like 6-row, 2-row pale or pilsner are high in diastatic power.
As Bob said, DME has no enzymes. Diastatic malt powder is usually a mixture of ground barley malt (with enzymes), wheat flour and sugar. It gives yeast a boost in baked products.
It has to be or it is? It seems like if you buzzed it in a food processor, maybe sifted it to remove a lot of the husk material, then used a spice grinde4 you would have a fine enough powder that would have the same effects.
Of course, not saying that making it from malted barley is the way to go I am just wondering if the result would b3 the same or similar. I did notice the item linked was out of stock. At any rate the next time I make bread I think I would like to whip some up from malt, it should take 10 minutes, then make a loaf with and one without.if I like the results it gives I would probably buy the ready to use product.