Determining the percentage of sulfur dioxide (SO2), used as a preservative in the process of drying in dried fruits such as apricots and figs.

摘要

Sulfur dioxide (SO2) is used as a preservative in the dried fruit industry to keep fruits from losing their original colour and taste however it is a poisonous chemical and can be lethal if exposed to in high levels.udI wondered the amount of sulfur dioxide we ingest by dried fruits unaware thus my research question for my experiment was “What is the percentage of sulfur dioxide (SO2), used as a preservative in the process of drying, in dried fruits such as apricots and figs, where the percentage of sulfur dioxide will be found with calculating the mass of barium sulfate precipitate (BaSO4) per fruit by first oxidizing the sulfur in sulfite ions (SO32-) to sulfate ions (SO42-) by adding 30 mL of 3% hydrogen peroxide (H2O2) and then precipitating the sulfate ions by adding barium chloride (BaCl2) drop by drop?”udI experimented on naturally dried figs, artificially dried figs, naturally dried apricots, artificially dried yellow apricots, artificially dried brown apricots to compare the percentages of SO2 in both naturally and artificially dried fruits. Although higher levels of SO2 was expected in artificially dried fruits (yellow apricots, the highest as more SO2 would be used to keep the light colour) and close to none expected in naturally dried ones, the lowest percentage was observed in artificially dried yellow apricots. The highest amount was found in artificially dried figs, followed by naturally dried apricots, naturally dried figs and then artificially dried brown apricots.udThe data did not give the results I had expected but my research showed that there is still enough SO2 in all dried fruit groups experimented on to possibly cause sulfite-sensitive individuals problems. The research should be expanded to many more food groups for the sake of general human health.