Many recipe sites now have metadata at the top of the page in json-ld or in embedded in the html based on schema.org structured data.

https://developers.google.com/search/docs/guides/intro-struc...

There are apps which can import from these sites. for example "recipe keeper", you can browse third party sites with schema.org recipes from inside the app and it will import them into the app management software.

Structured data typically maps to RDF, which is for graph databases like apache Jena or RDFox, but since most recipe data does not have backlinks or cyclical links, any type of JSON or YAML store should be sufficient.

If you are still updating your app, it would be cool if you could add support for recipes sites with json-ld!