As one of the five most common fruits in China

grapes are deeply loved by the vast majority of consumers. However

the problems of decay and softening of grapes are prevalent during storage and long-haul transportation. The activities of enzymes play important roles during this process. To study the effect of storage temperature on grape pectin content and related enzyme activities

the effects of four different storage temperatures—two super freezing temperatures (?3 °C and ?2 °C)

freezing temperature (?1 °C)

and common freezing temperature (4 °C)—on Italy grape pectin content and the pectinase activity have been analyzed. The study found that with the increase in storage time

the pectin content of the Italy grape pulp and pericarp decreased

and the soluble pectin increased. The decrease of the pectin content in pulp and the increase of soluble pectin content in pulp were the smallest at ?3 °C and the largest at 4 °C. In addition

changes in the content of pectin esterase and polygalacturonase in pulp and pericarp under the condition of super freezing temperature at ?3 °C were also less than those of other conditions. There was a significant positive correlation between the hardness of the Italy grape and the pectin and a significant negative correlation with the soluble pectin. This indicates that the super freezing temperature at ?3 °C can inhibit the hydrolysis rate of Italy grape pectin

so that the soluble pectin content can be controlled at a relatively low level

which can prevent the grape from softening. It can also inhibit the activity of pectin esterase in grape

reduce the promoting effect of polygalacturonase on grape pectin hydrolysis

and prevent Italy grapes from deteriorating during the storage period

which will further extend their storage time.