Evaluation of biochemical changes and gray mould during storage of Shahroodi table grapes under modified atmosphere packaging

The present research was conducted to evaluate the biochemical changes trends of Shahroodi table grapes tissues in a factorial experiment on the basis of completely randomized design with three replications under modified atmosphere packaging compared to the controls. Three gas combinations including 10%CO2+5%O2 (GC2), 10%CO2+15%O2 (GC3) and 10%CO2+60%O2 (GC4) using two types of polymeric films (polypropylene and polyethylene) were used to store grapes at 1 oC and 80-90% RH. The content of reducing sugars, total titratable acidity (TTA) and pH of fruit juice were measured every 15 days following the placing of fruits for 24 hrs at room temperatures. The results of 45 days storage showed that along with decreased reducing sugars content the infection incidence has been increased. On the other hand a sharp increase in reducing sugars content was observed after infection incidence. Our results showed that the early increase of reducing sugars content in the fruits of GC4 occurred along with less infection. In addition, it was observed that the decrease of TTA and increase of pH showed slower trends in these samples.