Utilization of response surface methodology for optimizing sweet sorghum juice extraction process

Efficiency of solid-liquid extraction of sweet sorghum juice strongly depends on the operating conditions. In this regard, the optimization of key process parameters such as temperature, time, and solid-to-liquid ratio was carried in this work using response surface methodology (RSM) with a view to maximizing recovery of soluble solid (RSS) and yield of the sweet sorghum juice. With the help of central composite design (CCD) of the RSM, these process variables were optimized within a range of 30 – 70 °C, 1 – 5 h, and 0.1 – 0.5 g/ml, respectively. Although the results revealed that all the three parameters had significant influence on the extraction process as evidenced by their corresponding p-values and F-values, the solid-to-liquid ratio and the temperature exerted the most pronounced influence on the RSS and juice yield, respectively. With quadratic model suggested from among the four models tested, the optimum temperature, time, and solid-to-liquid ratio were found to be 53.3 °C, 2.4 h, and 0.5 g/ml, respectively. At this condition, the extracted juice was predicted to contain RSS of 2.389 ⁰Brix with the yield of 59.5 %. These predicted responses were subsequently validated and the RSS in the extracted juice was found to be 2.403 ⁰Brix with the yield of 59.3%.