Good luck on the exams Noor! I would ALWAYS have a fast-acting snack with me during classes and exams. I also told my professors so that if they saw me eating, they would not think that I was being rude.
I used to keep fast acting snacks in a tupperware or rubbermaid mini container so it didn’t make noise if I had to eat it quickly during my exams.
There will be no ruffling of the wrapper or the like.