Cell wall polysaccharides of navy beans (Phaseolus vulgaris)

Cell wall (CW) materials of selected navy bean cultivars/line (C-20, Seafarer, Fleetwood, and experimental line 84004) were isolated and fractionated into six fractions: hot water soluble polymer (HWSP), ammonium oxalate soluble polymer (AOSP), hemicelluloses A and B, cellulose, and lignin. Seed coat CW was rich in cellulosic structural polysaccharides (range 58.7-65.0%) and lignin (range 1.4-1.9%), whereas cotyledon CW was composed principally of matrix polysaccharides and was especially rich in HWSP (range 25.7-32.5%) and H(B) (14.6-19.2%). Cotyledon CW contained 11-14% protein which was resistant to proteolysis and/or inaccessible to proteolytic enzymes. Fractionation of CW materials should provide a better basis for understanding the diverse physiological responses encountered when dietary fiber is consumed than if only dietary fiber, soluble fiber, or nonsoluble fiber is known.