Drying temperature

It depends on the moisture content of the grain. Barley malt kilning starts at a low temperature, say 130F and gradually ramps it up to 180F as the grain gets drier. If you used 180F straight away, the grain would cook.

Have a look here for some more detail.

So probably safest to go for 130F max, but if you have some means of increasing it slightly once the grain is practically dry, you might get a more interesting flavour.

Lance

Don't know if this will help but I dried some sprouted hard white wheat in a Presto dehydrator today in three hours at 105F. It was then milled in my Mockmill, introduced to some plain old white wheat, water, honey, yeast, salt and ghee. They seemed to get along swimmingly - perhaps swirlingly would be a better description. They spent some time happily riding the paddle and then the hook on the KA mixer. After all that excitement they napped briefly then happily climbed into the oven. Now they're inseparable. But I'm afraid they'll have to go under the knife tomorrow. I don't think I hurt the enzymes. It was the fastest bulk and proof I've ever seen in my 70F kitchen.

Nesco dehydrator.  Up to 115 is no worries though.  Amylase b denatures totally at 149 and a of the amylase enzymes is totally denatured at around 159 F but brewers need to get the wort temperature to 140 F to get the large starch molecules to swell so they are mire easily broken down into sugars by the amylase.  I ho;d my wort at 141-142 F to let the b amylase do its thing before raising the temperature to 150 F which denatures the b but the a then kicks in to do its thing.  The at the end I raise the temperature to over 165 F to denature all the enzymes.  Protease is in the same range as amylase.  So dry at even 115 - 120 F is no problem. These are plant based enzymes.

Animal based enzymes of the same kind fond in the human gut are usually denatured at over 105 F which isn't good to stay alive either.