Structural features of cell walls from potato (Solanum tuberosum L.) cultivars Irene and Nicola.

Cell wall material (CWM) isolated from non-cooked potato tissue of the cultivars Irene (mealy cooking) and Nicola (non-mealy cooking) was successively extracted with buffer, CDTA, Na2CO3 at 4 and 20 °C and 0.5 M KOH. The sugar composition of fractions and the remaining residues was determined. Information about the structure of the pectic polysaccharides was obtained by studying the degradation of the fractions and residues with purified polygalacturonase (PG) and rhamnogalacturonase (RGase). The results indicated that the pectic polysaccharides extracted by buffer, CDTA, and cold Na2CO3 contain more and/or longer side chains for cv. Irene than for cv. Nicola. From the CWM of cv. Nicola more branched and a higher amount of branched pectic polysaccharides were extracted with Na2CO3 at 20 °C and 0.5 M KOH, respectively, while the remaining CWM of cv. Irene contained 24% more residue. Keywords: Potato; Solanum tuberosum L.; texture; cell wall; middle lamella; polygalacturonase (PG); rhamnogalacturonase (RGas...