Changes in soluble carbohydrates and reactive oxygen species -scavenging enzymes activity in Medicinal Pumpkin during storage at varied temperature and moisture of seed

Seeds deterioration is a natural phenomenon that occurs in all seeds and leading to gradual decline of seed viability during storage. However، the rate at which seeds age depends upon their physiological status، genetic constitution and storage conditions. In the present study we the examined relationship between accumulation of reducing and non-reducing of sugars، soluble protein، the activity of free radical detoxifying enzymes، and seed deterioration in medicinal pumpkin during storage. The seeds were incubated at different storage conditions of temperature (35 and 5oC) and seed moisture content (5، 8 and 14%) for 2 and 4 days. The accumulation of reducing sugars increased and soluble proteins and non-reducing sugars decreased during storage with increasing moisture content and temperature، suggesting that seed deterioration was associated with Amadori and Maillard reactions. The decrease in soluble proteins was related with increased electrical conductivity، which suggests membrane damage during deterioration. The increase in electrical conductivity may result from some disorders in protein components of the membrane، which arise from non-enzymatic glycosylation of proteins by reducing sugars in the Amadori and Maillard reactions The decrease in germination was also associated with a decrease in catalase and peroxidase activity and as a result the antioxidant system was not sufficient to protect seeds against free radical damage. These results suggest that the accumulation of reducing sugar and decrease of soluble protein are coupled with Amadori and Maillard reactions and this reactions are responsible for medicinal pumpkin seed deterioration during seed ageing