مرکز منطقه ای اطلاع رساني علوم و فناوري - Research on Efficiency of Different Sulphur Dioxide Generators on Storability of Table Sultana Seedless Grapes

Abstract :

This study was conducted to determine the effects of different sulphur dioxide (SO2) generators on quality and storability of Sultana Seedless grapes. Grapes were harvested at fully ripe stage. The first group of samples were packaged and enclosed in SmartPac packages. The second group were packed in polyethylene bags. After the precooling process, the SO2 pads were placed at different positions as: above the grapes, at the top and bottom or no SO2 pads as the control group and then closed. SmartPac, with SO2 pads placed at the top and bottom had 4.5 g, 6.5 g and 1.5 g of sodium metabisulfite, respectively. Samples were stored at -0.5oC and 90% relative humidity for 4 months. During the storage period, SmartPac SO2 contents indicated a stable decrease and after 45 days there were no SO2 gas remaining in the packages. The samples that were placed with SO2 generating pads remained at SO2 concentrations ranging between 8 and 18 ppm during the storage. Different SO2 generating pads showed similar effects on berry removal force, color, total soluble solids, titratable acidity, maturity index and pH during two months storage. After 2 and 3 months of storage, decay development became significant in the control group and in SmartPac applications. The results showed that the Sultana Seedless grapes can be stored successfully for 2 months in SmartPac packages and 4 months with SO2 generating pads.