Optimization of Ultrasound Assisted Extraction of Functional Ingredients from Stevia Rebaudiana Bertoni Leaves

Abstract

A b s t r a c t. The aim of the present study was to reveal an effective extraction procedure for maximization of the yield of steviol glycosides and total phenolic compounds as well as antioxidant activity in stevia extracts. Ultrasound assisted extraction was compared with conventional solvent extraction. The examined solvents were water (100ºC/24 h) and 70% ethanol (at 70°C for 30 min). Qualitative and quantitative analyses of steviol glycosides in the extracts obtained were performed using high performance liquid chromatography. Total phenolic compounds, flavonoids, and radical scavenging capacity by 2, 2-azino-di-3-ethylbenzothialozine-sulphonic acid) assay were also determined. The highest content of steviol glycosides, total phenolic compounds, and flavonoids in stevia extracts were obtained when ultrasound assisted extraction was used. The antioxidant activity of the extracts was correlated with the total amount of phenolic compounds. The results indicated that the examined sonication parameters represented as the probe diameter (7 and 22 mm) and treatment time (2, 4, 6, 8, and 10 min) significantly contributed to the yield of steviol glycosides, total phenolic compounds, and flavonoids. The optimum conditions for the maximum yield of steviol glycosides, total phenolic compounds, and flavonoids were as follows: extraction time 10 min, probe diameter 22 mm, and temperature 81.2 o C. K e y w o r d s:

Ultrasound-assisted extraction of bioactive compounds from lemon balm and peppermint leaves

“…The highest value of the total phenolic content in the samples treated with ultrasound was determined in UES5 during 25 min of extraction (Table 2), while sample UES6 (extraction time 30 min) had even a lower content of phenolic compounds than sample UES4. The increasing trend of the total phenol content during the ultrasonic treatment for 30 min is expected, since the extraction time plays a key role in the separation of chemical compounds (Koubaa et al, 2015;Šic Žlabur et al, 2015). The results of total phenols extracted with the classical method show higher yields compared to the phenol results obtained in samples treated with ultrasound.…”

“…High intensity ultrasound treatment does not show any degradation rates on the content of bioactive compounds in the treated food products (Koubaa et al, 2015;Šic Žabur et al, 2015;Zinoviadou et al, 2015). In addition, high intensity ultrasound is applicable for extraction of compounds with various chemical structures and is characterized by non-invasive temperatures (Cvjetko Bubalo et al, 2013;Koubaa et al, 2015;Šic Žlabur et al, 2015). The ultrasound technique is extremely simple in application, and usually two types of equipment are used, including: -a system with a directly immersed ultrasonic probe (transducer) -an ultrasonic bath.…”

In vitro Propagation of Stevia rebaudiana (Bertoni): An Overview

“…The leaves of this plant has a pleasantly sweet and refreshing taste which is educe by diterpene glycosides (stevioside and rebaudiosides), a high-potency sweeteners and substitute to sugar, being 300 times sweeter than sucrose (Madan et al, 2010;Megeji et al, 2005;Singh and Rao, 2005;Soejarto et al, 1983;Soejarto DD, Kinghorn AD, 1982;Yadav et al, 2011). Stevia is a well-known therapeutic agent serve as an efficient medication for diabetes, hypertension, myocardial and antimicrobial infections, dental troubles, and tumors (Chan et al, 1998;Gregersen et al, 2004;Jayaraman et al, 2008;Jeppesen et al, 2003Jeppesen et al, , 2002Kujur et al, 2010;Marcinek and Krejpcio, 2016;Muanda et al, 2011;Philippe et al, 2014;Planas and Kucacute, 1968;Shivanna et al, 2013;Šic Žlabur et al, 2013;Singh et al, 2015). In present time people are very calorie conscious which increases use of stevia in preparation of non-calorie food stuffs and become a major sweetening agent in food products in South-east Asia (Ashwell,billion US dollar.…”

Water-soluble polysaccharides from Opuntia stricta Haw. fruit peels: recovery, identification and evaluation of their antioxidant activities

“…Plant extracts constitute natural sources of antioxidant compounds (Dent et al, 2013;Polya, 2003;Šic Žlabur et al, 2015). They are hence used in numerous applications ranging from phytotherapy to the modern food industries (Belton et al, 2003).…”