EVALUATION OF TRADITIONAL PRODUCTION PROCESS OF ROCK CANDY AND IT'S DEFECTS

Abstract

The rock candy is the grown sucrose crystal which has been produced in Iran and India for the first time originally. In this process, the large sucrose crystals has been produced by cooling the supersaturated solution. The traditional processing has not changed up to now. Recently, many efforts were done to optimize it. The production of rock candy evaluated under cooled crystallization process. To increase the yield and the growth of sucrose crystals, the supersaturation and crystallization parameters should be optimized. Due to low efficacy in this procedure, sucrose crystals with dimensions less than 3 mm are usually produced by evaporating crystallizers. In this research, traditional production process of rock candy is studied by doing experiments at different phases in a traditional plant. According to the results, it takes more than 90 min to reach the suitable supersaturation, an temperature (112°C) and extra evaporation. So the invert sugar content, reach from 0.015 % in original sugar to 0.571 % in effluent (mother syrup). The produced rock candy has 0.553 % invert sugar. The pH of solution decreases from 7.3 to 5.2, the color increased from 70 (in primary sugar) to 1240 ICUMSA unit in the effluent and more than 250 Iu in produced rock candy (measurement in λ = 420nm ). The high color rate and invert sugar cause the effluent can not be used in production process. Key words: sucrose, rock candy, crystallization, supersaturation.