An Experimental Study of the Effects of the Mud Boil-up Process on the Physico-Chemical Properties of Grape Syrup

The deficiency of calcium, magnesium, potassium, and iron leads to severe disorders in human body organs. This study introduces the Dooshab as a food source of these useful elements. The Dooshab which translates to grape syrup is widely used in Iran. In the traditional method of the Dooshab production, the white soil is added to the grape juice and the mixture is boiled. After cooling, it is filtered. To get the syrup, the filtered juice is boiled again and concentrated. In this research grape juice was divided into two equal parts. A known amount of white soil was added to one of the samples. Then, both samples were boiled and left to cool down. After paper filtering, the pH of each sample was measured. Heating was continued until liquids were concentrated and converted to syrup. Both samples which are produced from using mud-boiled up stage and skipping this step were diluted to fixed volumes. Similar amounts of two samples were ashed and dissolved in distilled water and tested. The atomic absorption spectroscopy, spectrophotometry, and flame atomic emission spectroscopy techniques were used for quantitative analyses. The calcium, magnesium, iron and potassium quantity are 12 mg, 6.82 mg, 2.32 mg, and 250 mg in 25 mL of the Dooshab and 1.75 mg, 0.65 mg, 1.28 mg, and 65 mg in 25 mL of grape sauce, respectively. This study demonstrates that boiling of grape juice with the white soil decreases the acidity and increases the amounts of useful elements in grape syrup.