The effect of sulphur dioxide (SO2) and drying methods in chemical and bioactive indicators and antioxidant activity in local yellowish Baladi grape


Abstract in English

This study was carried out in the laboratories of the Faculty of Agriculture, Damascus University in 2012 season. Clusters of local yellowish baladi grape exposed to the concentration (2000 Ppm) of gas SO2 for 3 hours were dried to moisture content not exceeded 18% by different drying methods (sun drying, heat drying, solar energy-green house) in the aim of determining their effect on some chemical indices (total sugar, pH, acidity, solid soluble, non enzymatic browning), some antioxidants (vitamin C, total phenols) and antioxidant activity according to 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The results showed superiority (p<0.05) of the way solar drying of the fruits of the grape-treatment with gas SO2 to maintain vitamin C (7.17 mg/ 100 g dry weight) while outperformed the fruits of grapes dried with heat treatment and gas SO2 in content of phenols (7.24 mg acid Gaelic/ 100 g dry weight). Results also showed that samples of grapes dried solar and non-treated with gas SO2 noticeable increase in its activity in the antioxidant, which amounted to 82.42%. The results confirmed that the importance of treatment with gas SO2 prior to the fruits of grapes in reducing (p<0.05) the time required to complete the drying process, especially in the way of thermal drying to (137 hours) compared with other transactions.

References used

AOAC. 2000. Association of official analytical chemists, official methods of analysis, 17th Ed, Washington DC, 1-43
AOAC. 2005. Determination of moisture, ash, protein and fat. Official methods of analysis. 18th Ed. Association of official analytical chemists, washington, DC
Asami, D. K., Y. J. Hong, D. M. Barrett and A.E. Mitchell. 2003. Comparison of the total phenol and ascorbic acid content of freeze – dried and air dried Marino berry, strawberry and corn grown using conventional, organic and sustainable agricultural practices. Journal of Agricultural and Food Chemistry, 51(5):1237-1241

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