Évolution des pectines et des activités polygalacturonases au cours de la maturation de la datte Deglet-nour

Abstract

Evolution of pectins and polygalacturonase activities during maturation of date Deglet-nour During storage, the date undergoes several changes that affect its organoleptic characters. The characterisation of the parameters which induce these evolutions was carried out for understanding the biochemical mechanisms in order to select the conditions assuring the stability of the date during its storage preserving its nutritional value and its commercial value. The extraction and the fractionation of pectic substances were achieved as a function of the ripening of the date which contained about 2% of total pectin. The observed degradation of these pectin was ascribed to the presence of PG, a pectolytic enzyme responsible for the softening of fruit; indeed the PG activity increased during the stages of development with a maximal activity at the last stage (0.53 Ul/g Fresh Matter). The date polygalacturonase will be an exopolygalacturonase which presents an optimal activity at the temperature 40 degrees C and pH 5.