Influence of Extraction Methods on the Yield of Steviol Glycosides and Antioxidants in Stevia rebaudiana Extracts.
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.
Institute of Food Engineering for Development (IUIAD). Food Technology Department (DTA), Universitat Politècnica de València, P.O. Box 46022, Valencia, Spain.
Angela
A
Periche
Maria Luisa
ML
Castelló
Ana
A
Heredia
Isabel
I
Escriche
D000975:Antioxidants / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D045786:Diterpenes, Kaurane / Q000032:analysis*; D005419:Flavonoids / Q000032:analysis; D006027:Glycosides / Q000032:analysis*; D008872:Microwaves; D019800:Phenol / Q000032:analysis; D010936:Plant Extracts / Q000032:analysis*; D018515:Plant Leaves / Q000737:chemistry; D025341:Principal Component Analysis; D015203:Reproducibility of Results; D036625:Stevia / Q000737:chemistry*; D013696:Temperature; D000069453:Ultrasonic Waves
D000975:Antioxidants; D045786:Diterpenes, Kaurane; D005419:Flavonoids; D006027:Glycosides; D010936:Plant Extracts; D019800:Phenol; C012042:steviol