Effect of process parameters on stevioside and rebaudioside A content of stevia extract obtained by decanter centrifuge

Abstract

The aim of this research is to determine the possibility of decanter extraction for the isolation of steviol glycosides from stevia leaves. Extraction parameters such as temperature, time, and leaf/water ratio were optimized by using “Response Surface Methodology.” The optimal combination determined as a result of optimization studies was 25°C, 1/27.6 leaf/water ratio, and 105 min extraction time. Under these conditions, experiments were carried out at three different speeds of 4,500, 4,900, and 5,280 rpm (2,264, 2,684, 3,117 g, respectively) in a decanter extraction system to investigate the effect of rotational speed. The amount of stevioside in samples obtained at 4,500, 4,900, and 5,280 rpm was 1080.82, 1919.18, and 2507.35 mg/L, respectively. The amount of rebaudioside A was 761.34, 1417.17, and 1801.93 mg/L, respectively. Results showed that the rotational speed of the decanter had a considerable effect on all the parameters examined. Practical applications Stevia is a product that is widely used in food formulations in the scope of combating obesity and diabetes. In this study, the decanter was applied for the first time to extract stevia leaves and optimum process conditions for decanter extraction of steviol glycosides were determined. It has been observed that stevia extraction can be successfully performed at 25°C with high efficiency using decanter. The yield of the extract increased with increasing decanter rotational speed. The decanter extracted 73% of the total stevioside and rebaudioside A present in the leaves. The results of this study may be used by manufacturers who want to process the stevia plant with more economical and environmentalist approaches.