For my prototype I decided to create a knife that related to our ‘Foodie’ app, which is an app where the user can customize the nutrients of the fruit and vegetable and create different combinations of them and be able to order it. With my knife I wanted design something that could diminish the nutrients the user ordered in the app within their fruit or vegetables, in case their dietary requirements change between the time they order the fruit/veg from the app to when it’s delivered or if they are lacking in certain vitamins.
My first idea was to have a serum where you could drop it onto the fruit/veg and it would neutralize it then you could brush on the vitamins you wanted. However I received feedback and decided to create a knife that had a type of brush on it so when you cut the fruit the serum that you drop into the top of the knife, will go on the bristles and coat the fruit or veg.
I then further received feedback on this idea and changed it to a small sponge on the knife instead of a brush, I also made the serums insert into the top of the knife where we the user holds it from. 
In the image above the serum inserts at the top, you level the end of the knifes handle to the amount of doses you want. In each serum there is around four and a half doses.
Once you have neutralised your fruit/veg you can rinse the knife and insert the vitamin you want and level it to the amount of dosage you want. You then swipe the sponge on the fruit, and there you have it an apple with calcium in it!
The Foodture 