To modify Tasty Items, you only need to unpack it and paste this "assets" folder on the same folder you have the "assets" folder for that pack. It will ask if you want to replace wish to replaced duplicate files and you select yes, this will alter and add the modifiers files to tasty items. After that is done, just pack the files for Tasty Items and add it to your resource packs folder, you may now enjoy the altered version of the pack.