Foodreel / Food Reel / Food Demo is, in general, the portfolio of the food director or tabletop director. It contains the most beautiful shots put together creating one longer movie. It is usually built with the best shots from different foodfilms done in recent time of the director to present his capabilities.
Foodreel - special type of demoreel
Tabletop Demoreels / showreels, in general, are used by many kinds of people involved in filmmaking and other media, including actors, animators, lighting designers, editors and others. Usually are up to 3 minutes in length. Typically a demo reel/showreel supplements a résumé and is used to promote an author to talent agents, producers and casting directors.
Outside of people and companies directly involved with tabletop video or film production, companies use showreels for brand management and other forms of marketing communications and public relations.
If you want to see more examples, look at director pages, for example Kevan Bean, Ben Flaxman, Nick Sawyer, Irv Blitz, Olaf van Gerven.