Carbon dioxide treatment as a potential alternative to sulfur dioxide to control fruit decay in Red Globe table grape.

摘要

To reduce postharvest losses and fruit decay, and to maintain fruit quality of grape (Vitis vinifera) cv. Red Globe, fruits were treated with either sulfur dioxide (SO2) or carbon dioxide (CO2). Two different releasing rates of SO2 (0.5 and 1%) fromgenerating pads were used; moreover, three different positions of SO2 generating pads were used inside the packages (at the top, bottom or both). Carbon dioxide was applied at three different concentrations (2.5, 5 or 7.5%). Fruits were stored at 0℃, and 90% RH. Both physical and chemical properties were recorded at weekly intervals. Both SO2 and CO2 applications significantly reduced fruit decay percentage, total weight loss percentage, and shatter percentage over the control. In addition, they improved berry firmness and berry adherence strength. After 6 weeks of treatment, CO2 treatment at 7.5% and SO2 pads (at both double or upper positions) resulted in a significantly lower fruit weight loss, shatter percentage, and decay percentage, and significantly higher berry firmness and berry adherence strength than those treated with lower SO2 pad positions and the control. No significant differences were observed between SO2 releasing pads at either the upper or the double positions. Both CO2 and SO2 treatments significantly reduced fruit pathogenic infection, and subsequently reduced fruit losses percentage. However, fruit quality was not affected by either CO2 or SO2 treatments especially fruits treated with either CO2 at 7.5% or SO2 pads at upper position as they looked like most closely the fresh control treatment. Both CO2 at 7.5% and SO2 pads at both double or upper positions showed superiority over all other treatments and resulted in better quality attributes as it maintained fruit colour, soluble solid content, and better fruit rupture force.