Lignin is a polyphenolic cell wall constituent, which is integrated into the cell wall starting with the deposition of the secondary cell wall. The lignin content and/or structure have been suggested to determine several textural and physiological properties of plant-based foods. For example, lignification of edible tissues of plants is discussed to negatively affect sensory properties of certain vegetables. The interaction of lignified cell walls with specific contaminants such as heterocyclic aromatic amines, however, is considered a positive effect of lignin in plant-based food products. Despite these potential effects of lignins on plant-based food quality and functionality, knowledge about lignins from edible plant organs is rather limited; hardly any structural studies are available. “Quantitative” data are usually gathered from the unspecific “Klason-lignin” methodology. We structurally analyze lignins from a variety of cereal grains, fruits, and vegetables by using mass spectrometric and in-depth NMR approaches to determine the monolignol composition of and linkage types in these lignins. For example, our studies revealed that cereal brans were falsely claimed to be “highly lignified”. Because we questioned the results from the Klason-lignin methodology as applied to food, we have analyzed the composition of Klason-lignins isolated from different dietary fibers and demonstrated that the majority of “Klason-lignin” is made up of non-lignin compounds. In addition, we strive to understand the lignin deposition during ripening and storage of plant based food products and how lignin interacts with (food-borne) contaminants (see also: Interactions of cell wall components with contaminants).