This might be of interest to you, I think it would do what your are trying to achieve perfectly.
However
I think the one “issue” would be, the enrolling of every item in you pantry, then removing it (and the RFID sticker? that you can buy cheaply from China shopping sites) from your inventory and then attaching a new RFID sticker to every new item after shopping 
and enrolling it into your inventory.
Though it pains me to say it, I think you would be better suited looking at a barcode system, since manufacturers have already done the “sticker” part for you, and you can get an app like
and you can use your phone to read the Barcodes.
It all sounds like a “fun” project, but a little too much work for me, I would accept my fate of “too much” pasta sauce and think of it as an investment into food stocks for the upcoming apocalypse 
Good luck, and let us know what path you take and how it goes…