Cell wall polysaccharides and lignin in cotyledons and hulls of seeds from various lupin (Lupinus L.) species

Cell wall constituents have been analysed in cotyledons and hulls of eleven species of lupins ( Lupinus albus, angustifolius, elegans, graecus, hispanicus, luteus, mutabilis, pilosus, subcarnosus, succulentus and varius ) and in five varieties of white lupin ( Lupinus albus ). Cotyledon cell walls obtained after defatting and pronase treatment of dehulled flours ranged from 7% of dry matter in L. elegans to 32% in L. pilosus and essentially consisted of galactose, arabinose and galacturonic acid residues. Wall content was closely related to galactose percent, an increase in cell wall proportion likely being due to branching of additional galactan side‐chains on rhamnogalacturonans. Hulls were mainly constituted of cellulose associated with hemicellulosic and pectic polymers. Most lupin hulls had low lignin contents.