CELL-WALL DISSOLUTION DURING INDUSTRIAL PROCESSING OF GREEN BEANS (PHASEOLUS-VULGARIS L)

Cell wall material was isolated from fresh and industrially processed green beans using two cultivars and two different isolation methods. T he chemical composition of the cell wall fractions was compared, and t he structure of the water-insoluble polymers was investigated by methy lation analysis. This study indicated that the major cell wall polysac charides of green bean pods were cellulose and pectin, but hemicellulo ses were also detected. Major cell wall changes occurred during the st erilization process. Homogalacturonan was partially degraded, and on a verage 68% of the pectin was solubilized during this process. Sugar an alyses indicated that either pectin-associated or hemicellulosic arabi nogalactans remained immobilized within the residual cell wall matrix after sterilization. Processing did not affect the overall degree of a cetylation. However, the overall degree of methylation decreased after sterilization, most likely predominantly caused by beta-eliminative b reakdown of highly methylated homogalacturonan regions of the pectin d uring the heating process.