Influence of Extraction Methods on the Yield of Steviol Glycosides and Antioxidants in Stevia rebaudiana Extracts
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This study evaluated the application of ultrasound techniques and microwave energy, compared to conventional extraction methods (high temperatures at atmospheric pressure), for the solid–liquid extraction of steviol glycosides (sweeteners) and antioxidants (total phenols, flavonoids and antioxidant capacity) from dehydrated Stevia leaves. Different temperatures (from 50 to 100 °C), times (from 1 to 40 min) and microwave powers (1.98 and 3.30 W/g extract) were used. There was a great difference in the resulting yields according to the treatments applied. Steviol glycosides and antioxidants were negatively correlated; therefore, there is no single treatment suitable for obtaining the highest yield in both groups of compounds simultaneously. The greatest yield of steviol glycosides was obtained with microwave energy (3.30 W/g extract, 2 min), whereas, the conventional method (90 °C, 1 min) was the most suitable for antioxidant extraction. Consequently, the best process depends on the subsequent use (sweetener or antioxidant) of the aqueous extract of Stevia leaves.
KeywordsMicrowave energy Ultrasound technique Antioxidants Phenols Flavonoids Steviol glycosides
The authors thank the Universitat Politècnica de València for funding the project PAID 2011-ref: 2012 and the Generalitat Valenciana (Spain) for the project GV/2013/029.
Conflict of Interest
The authors declare that they have no conflict of interest.
- 2.JECFA. Joint FAO/WHO Expert Committee on Food Additives (2008) Steviol glycosides. In Compendium of Food Additive Specifications, 69th Meeting, FAO/WHO Monographs 5, Rome, ItalyGoogle Scholar
- 10.Kroyer J (2010) Stevioside and Stevia-sweeter in food: application, stability and interaction with food ingredients. Journal of Consumer Protection and Food Safety. doi:10.1007/s00003-010-0557-3
- 18.Yang L, Cao YL, Jiang JG, Lin QS, Chen J, Zhu L (2010) Response surface optimization of ultrasound-assisted flavonoids extraction from the flower of Citrus aurantium L. var. amara. Engl J Sep Sci 33:1349–1355Google Scholar
- 23.Commission Decision 2002/657/EC of 12 August (2002). Implementing Council Directive 96/23/EC concerning the performance of analytical methods and the interpretation of results, OJEC L221, 8–36. Brusels, BelgiumGoogle Scholar
- 28.Kennelly E (2002) Sweet and non-sweet constituents of Stevia rebaudiana (Bertoni) Bertoni. Stevia, the Genus of Stevia, Medicinal and aromatic plants- industrial profiles. Ed. Taylor and Francis, London, ISBN: 0-415-26830-3, 68–85.Google Scholar
- 30.Zhang G, He L, Hu M (2011) Optimized ultrasonic-assisted extraction of flavonoids from Prunella vulgaris L. and evaluation of antioxidant activities in vitro. Innov Food Sci Emerg 12:18–25Google Scholar