Methods for the preparation of cell walls from potatoes

A group of new methods is described for preparing cell walls from potatoes and processed potato products. Starting from raw domestic potatoes, starch is degraded enzymatically after a very brief 100 °C gelatinisation step conducted after homogenisation to minimise the time required for heat transfer. Protein is removed by detergent and phenol extraction. This procedure (method 1) gave cell wall preparations containing <5␜tarch, with minimal degradation of wall polysaccharides. It did not, however, remove starch efficiently from industrial potatoes in which the starch content is much higher. A different procedure, method 2, was used in this case. In method 2 a 20 min starch gelatinisation step was used but the temperature was restricted to 70 °C and the pH to 4.0, with the aim of protecting pectins from depolymerisation. Method 2 and method 1A, which is a hybrid procedure involving the starch gelatinisation step from method 2 and other steps from method 1, gave low-starch cell walls from industrial as well as domestic potatoes. These methods are suitable for a range of potato types and potato products and are either more efficient or more convenient than previous procedures for cell wall isolation.