Food definition and classification
A specific food ontology was built, based on the LanguaL system (2). LanguaL is a food description thesaurus that provides a standardized language using facetted classification. Each food is described by a set of controlled terms, such as the botanical origin, food processing including cooking and conservation. The exact identity of the foods described in the original sources was checked and botanical names added using botanical databases and other resources (3, 4, 5). It was sometimes necessary to separate some specific groups of cultivars because of their clearly different polyphenol profiles (e.g. blond orange and blood orange). However, for other foods, cultivars were not differentiated due to the lack of sufficient analytical data.