Enhancing the aqueous extraction of stevia glycosides from stevia rebaudlanaleaves under the action of electric discharge pretreatment
2009
Negm, M.S. | Mahmoud, A.H. | Badr, F.H. | El-Badawi, A.A.I.
The Extraction of the natural sweetening glycosides from Stevia rebaudiana leaves (Steviosides) can be processed by several methods such as hot water, alcohols (methanol or ethanol) or supercritical fluid extraction. Water is an environmentally friendly and economically preferable alternative to harmful organic solvents in spite of its inferior efficacy. Therefore, different high voltage electric discharge (HVED) treatments (intensity 40 KV cm-1 and 50, 125, and 200 pulses) were used to enhance the water extraction of Stevioside. The extraction kinetics was studied at two temperatures (20 and 55°C) with agitation during 60 minutes. Experimental data were fitted by simplified empirical model. The extract quality was determined by spectrum scanning at wavelength range 190-700 nm for all treatments. The results indicated generally that the HVED treatments accelerated the extraction process of glycosides with a better quality comparing with a control at the end of extraction time.
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