I will go against the grain and say you’ll be fine.
They will pull ypur backpack aside and ask ypu to retrieve the powder. They’ll test in with a special machine they have and then let you have it back.
True story:
I was travelling with 5 boiled eggs with no shells on as a snack in a ikea bag like yours. I took them because I did not want to leave them in my fridge. They pulled my backpack aside and did what I described above.
At another time, this time funnier. My cousin is a baker and I took in my backpack a pack of marzipan 1kg. As you can imagine, it resembles a brick of cocaine so that one got the same treatment.
For children travelling with boiled water or premade milk bottles they can go through security but they put them in the machine too.
And last one. This happened to my dad, he was travelling with a perfume I gifted to him, 100ml. Should not have been a problem, only there was as the liquid had the same colour blue from when drugs are tested and reactive. It got checked too with the aforementioned machine.
All passed, except for a bottle of strawberry syrup my daughter stowed away in her backpack, bless her.