Removal of Sulfur Dioxide from Dried Grapes before Handling

Tawfik, Magdy Fouad; Yousef, Eman El Sayed; Aboul Fotouh, Mohamed Mahmoud; Farag, Hanaa Rizk Mohamed

doi:10.21608/ejchem.2024.302677.9969

Removal of Sulfur Dioxide from Dried Grapes before Handling

Document Type : Original Article

Authors

¹ Agricultural Biochemistry, Faculty of Agriculture, Ain Shams University, Cairo, Egypt

² Food Science Department, Faculty of Agricultural, Ain Shams University, Egypt

³ Biochemistry, Faculty of Agriculture, Ain Shams University, Cairo, Egypt

⁴ Agricultural Biochemistry Department, Faculty of Agriculture, Ain Shams University, Cairo, Egypt

10.21608/ejchem.2024.302677.9969

Abstract

Dried grapes or raisins are usually treated with sulfur dioxide in high concentrations to prevent enzymatic and non-enzymatic browning reactions and keep golden yellow color of these dried fruits. Sulfur dioxide and sulfite salts are good food preservatives but have high risk on human health especially when using in high concentrations. Thus, this work was achieved to remove sulfur dioxide and sulfite salts from over sulfite raisins before handling in different food industries into lower concentrations by soaking of raisins in water, H2O2 (1%), citric acid (5%) and acetic acid (5%) at 30 and 50oC for 15 and 30 minutes. These treatments led to removing high amounts of sulfur dioxide and sulfite salts from raisins especially with treatment by citric acid (5%) at 50oC for 15 min. Comparatively, soaking of raisins in citric acid (5%) was the best treatment followed by acetic acid (5%) and H2O2 (1%) then water. This work also aimed to desulfurization of raisins with minimal effects on their constituents e.g. total phenols, tannins, flavonoids and color features. The loss rates of these constituents from raisins obtained by the soaking treatments in water were lower than those obtained by citric acid (5%) then acetic acid (5%) while the maximum loss rates of these constituents from raisins were obtained by H2O2 because it is oxidizing and bleaching agent. Therefore this work was achieved to overcome this problem by using citric acid or acetic acid instead of H2O2.

Keywords

Main Subjects