scholarly journals Optimization of microwave assisted enzymatic extraction of steviol glycosides and phenolic compounds from Stevia leaf

2019 ◽  
pp. 69-76
Author(s):  
Ahmet Görgüç ◽  
Esra Gençdağ ◽  
Fatih Yılmaz

Stevia (Stevia rebaudiana Bertoni) has gained great interests due to its non-caloric and health related properties with its steviol glycosides and phytochemical constituents. Currently, it is being utilized as a natural sweetener in many food formulations such as soft drinks, jams, dairy products, chocolates, etc. Green extraction techniques using non-hazardous solvents and yield-enhancing strategies have been subject matters of various disciplines such as food technology, chemistry and pharmacology. Stevia powders are industrially produced by aqueous-extraction with further purification and drying steps. There has been no any report handling combined microwave and enzyme assisted technique on the extraction of steviol glycosides and antioxidant compounds to date. The objective of this study was to determine optimum processing parameters of microwave assisted enzymatic extraction of steviol glycosides and phenolic compounds by investigating the effects of independent variables. The plant was collected from a stevia garden and its leaves were detached from flower part, dried and milled into powder form before commencement of the treatments. Operations were performed using a microwave extraction system equipped with a digital control system for irradiation time, temperature and microwave power. Viscozyme L which is a widely used cellulolytic enzyme cocktail was used in this study. The effects of enzyme concentration (1.2 - 60 FBG unit g-1), temperature (25-60?C) and time (1 - 20 min) were evaluated using a five-level rotatable central composite design by response surface methodology (RSM). The validities of models were assessed by ANOVA outputs which were determination coefficient (R2), lack of fit and Fisher's test value (F-value). The maximized yields of stevioside, rebaudioside A and total phenolic compounds were determined as 62.5, 25.6 and 20.7 mg g-1, respectively at optimum processing conditions which were estimated as 10.9 FBG unit g-1, 53?C and 16 min.

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1202 ◽  
Author(s):  
Jana Šic Žlabur ◽  
Nadica Dobričević ◽  
Mladen Brnčić ◽  
Francisco J. Barba ◽  
Jose M. Lorenzo ◽  
...  

In this study, the influence of stevia addition and sonication processing parameters on the phenolic content and profile as well as the steviol glycosides of strawberry juice-based samples was investigated. For this purpose, three matrices—control samples of strawberry juices without green stevia powder (CS), strawberry juices with green stevia powder (JGSP), and sonicated juices with green stevia powder (SJGSP)—were prepared. For sonication purposes, different conditions regarding probe diameters (7 mm and 22 mm), amplitudes (50%, 75%, and 100%), and time (15 min, 20 min, and 25 min) were tested. The results that were obtained upon the measurement of the total phenolic content, total flavonoids, steviol glycosides, and antioxidant capacity showed significant differences according to the matrices evaluated, obtaining overall higher values in the samples with stevia added. Moreover, when sonication was evaluated, it was found that a higher amplitude (100%), a larger probe diameter (22 mm), and a longer sonication period (25 min) led to higher values. Flavones such as luteolin and apigenin were identified and quantified in JGSP and SJGSP, while they were not found in CS. Besides these phenolic compounds, kaempferol, quercetin, pyrogallic acid, 4-methylcatechol, and 4-methoxybenzoic acid were also identified and quantified. Similarly to the total phenolic compounds, total flavonoids, and total antioxidant capacity, an increased amount of these compounds was found in SJGSP, especially after using the most intense sonication conditions. Therefore, the use of sonication together with stevia added could be a useful tool to preserve strawberry juices, increasing at the same time the sweetness and the antioxidant value of the beverages.


2019 ◽  
Vol 5 (1) ◽  
pp. 16-28
Author(s):  
Oluwaseun Ruth Alara ◽  
Nour Hamid Abdurahman ◽  
John Adewole Alara

Vernonia cinerea is one of the medicinal plants with several potentials for treating different ailments. In the present study, Microwave-assisted extraction (MAE) was employed in extracting phenolics compounds from this plant. However, different factors that affect this extraction method in the recovery of phenolics compounds abound, these factors need to be screened to determine actual contributing factor in order to minimize cost. Irradiation time (1-5 min), ethanol concentration (20-60% v/v), microwave power (40-80 W), extraction temperature (40-80 oC), and feed/solvent (1:10 - 1:18 g/mL) have been screened using two-factorial design for the recoveries of phenolic compounds from V. cinerea leaves. The results obtained in this study indicated that only microwave power, ethanol concentration, irradiation time and feed/solvent contributed to recoveries of total phenolic content (TPC) and total flavonoid content (TFC) from V. cinerea leaves. Thus, these factors at these ranges can be further optimized to obtain optimal yields of phenolic compounds from V. cinerea leaves.


Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2498 ◽  
Author(s):  
Cai-Ning Zhao ◽  
Jiao-Jiao Zhang ◽  
Ya Li ◽  
Xiao Meng ◽  
Hua-Bin Li

A microwave-assisted extraction (MAE) technology optimized by response surface methodology (RSM) was established to extract phenolic compounds from the fruit of Melastoma sanguineum. The effects of solvent composition, ratio of solvent to material, temperature, time and microwave power on phenol yield were evaluated in single-factor tests. The three parameters exerting main impacts on phenol yield were further optimized by RSM. Under optimal extraction conditions (31.33% ethanol, solvent/material ratio of 32.21 mL/g, 52.24 °C, 45 min and 500 W), the total phenolic content was 39.02 ± 0.73 mg gallic acid equivalent (GAE)/g dry weight (DW). This MAE method performed better in comparison with two conventional methods, those being maceration (25.79 ± 1.03 mg GAE/g DW) and Soxhlet extraction (18.40 ± 1.34 mg GAE/g DW), using lower process temperature, shorter irradiation time, and lower organic solvent consumption. In addition, five flavonoids (epicatechin gallate, epicatechin, rutin, pigallocatechin and quercetin) and two phenolic acids (protocatechuic acid and chlorogenic acid) in the extract were identified and quantified using UPLC-MS/MS.


Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1593
Author(s):  
Iván Gómez-López ◽  
Gloria Lobo-Rodrigo ◽  
María P. Portillo ◽  
M. Pilar Cano

The aim of the present study was the full characterization, quantification, and determination of the digestive stability and bioaccessibility of individual betalain and phenolic compounds of Opuntia stricta, var. Dillenii fresh fruits (peel, pulp, and whole fruit) and of the products of the industrialization to obtain jam (raw pressed juice (product used for jam formulation), by-product (bagasse), and frozen whole fruit (starting material for jam production)). Opuntia stricta var. Dillenii fruits and products profile showed 60 betalain and phenolic compounds that were identified and quantified by HPLC-DAD-ESI/MS and HPLC-DAD-MS/QTOF, being 25 phenolic acids (including isomers and derivatives), 12 flavonoids (including glycosides), 3 ellagic acids (including glycosides and derivative), and 20 betanins (including degradation compounds). In vitro gastrointestinal digestion was performed by INFOGEST® protocol. Fruit pulp showed the greater content of total betalains (444.77 mg/100 g f.w.), and jam only showed very low amounts of two betanin degradation compounds, Cyclo-dopa-5-O-β-glucoside (and its isomer) (0.63 mg/100 f.w.), and two Phyllocactin derivatives (1.04 mg/100 g f.w.). Meanwhile, fruit peel was the richer tissue in total phenolic acids (273.42 mg/100 g f.w.), mainly in piscidic acid content and total flavonoids (7.39 mg/100 g f.w.), isorhamnetin glucoxyl-rhamnosyl-pentoside (IG2) being the most abundant of these compounds. The stability of betalains and phenolic compounds during in vitro gastrointestinal digestion is reported in the present study. In Opuntia stricta var. Dillenii pulp (the edible fraction of the fresh fruit), the betanin bioaccessibility was only 22.9%, and the flavonoid bioaccessibility ranged from 53.7% to 30.6%, depending on the compound. In non-edible samples, such as peel sample (PE), the betanin bioaccessibility was 42.5% and the greater bioaccessibility in flavonoids was observed for quercetin glycoside (QG1) 53.7%, the fruit peel being the most interesting material to obtain antioxidant extracts, attending to its composition on antioxidant compounds and their bioaccessibilities.


2020 ◽  
Vol 16 (1-2) ◽  
Author(s):  
Cassiano Brown da Rocha ◽  
Caciano Pelayo Zapata Noreña

AbstractThe grape pomace is a by-product from the industrial processing of grape juice, which can be used as a source of bioactive compounds. The aim of this study was to separate the phenolic compounds from grape pomace using an acidic aqueous solution with 2 % citric acid as a solvent, using both ultrasound-assisted extraction, with powers of 250, 350 and 450 W and times of 5, 10 and 15 min, and microwave-assisted extraction using powers of 600, 800 and 1,000 W and times of 5, 7 and 10 min. The results showed that for both methods of extraction, the contents of total phenolic compounds and antioxidant activity by ABTS and DPPH increased with time, and microwave at 1,000 W for 10 min corresponded to the best extraction condition. However, the contents of phenolic compounds and antioxidant activity were lower than exhaustive extraction using acidified methanol solution.


2013 ◽  
Vol 41 (1) ◽  
pp. 136 ◽  
Author(s):  
Violeta NOUR ◽  
Ion TRANDAFIR ◽  
Mira E. IONICA

Ten indeterminate tomato cultivars differing in fruit shape and typology, grown simultaneously in a greenhouse from Oltenia (Southwestern Romania) and harvested at red ripe stage, were investigated for the contents in ascorbic acid, lycopene, β-carotene, total phenolics, minerals (K, Na, Ca and Mg) and trace elements (Fe, Cu, Mn, Cr, Zn and B). In addition, their antioxidant activities were determined. Significant differences were found among tomato cultivars in all studied antioxidant compounds, as well as in the antioxidant activity. Ascorbic acid ranged from 91.9 to 329.7 mg kg-1 fw, lycopene ranged from 19.7 to 49.0 mg kg-1 fw, while total phenolic compounds varied between 300.2 and 557.8 mg kg-1 fw. Antioxidant activity ranged from 0.81 mmol Trolox kg-1 fw to 1.74 mmol Trolox kg-1 fw and it was significantly correlated to total phenolics content (r = 0.91; p< 0.05). The cocktail type cultivar ‘Tiger’ and the cherry type cultivar ‘Belle’ proved to be the most powerful in antioxidant activity and phenolic compounds while the rectangular plum shaped cultivar ‘Porto’ recorded the highest average lycopene content. A valuable cultivar proved to be the brownish red ‘Sacher’ which registered among the highest contents of phenolics, lycopene and ascorbic acid. Mineral and trace elements contents were also significantly affected by cultivars. Values recorded for K, Ca and Mg ranged from 2139.6 to 3056.9 mg kg-1, 137.7 to 325.8 mg kg-1 and 27.3 to 168.7 mg kg-1 respectively.


Ingeniería ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 77-92
Author(s):  
Ciliana Florez Montes ◽  
Andrés Felipe Rojas González ◽  
Sneyder Rodríguez Barona

Context: Currently, the increase in agroindustrial waste generation has encouraged the search for viable use alternatives. In this paper, four methods to obtain extracts from mango, soursop, and grape peels, as well as and grape seeds, are studied. Their efficiency is analyzed through extraction yields and antioxidant capacity characterization of the extracts. Method: The extraction was performed using solvent, Soxhlet, microwave-assisted, and ultrasound assisted extraction. The characterization of the extracts was made by total phenolic compounds and flavonoids quantification, as well as antioxidant capacity determination, using the DPPH, FRAP, and ORAC tests. Results: It was found that grape seed extracts obtained by different extraction methods, highlighting those obtained by microwave assisted extraction, present a high total content phenolic compounds (>321.381,41 ± 3.476,85 μg Gallic Acid/g) and flavonoids (>103.232,01 ± 4.638,19 μg Quercetin/g), in addition to high antioxidant activity, according to the results of the DPPH (<1,06 ± 0,01), FRAP (>152.280,08 ± 5.197,53 µg TROLOX/g), and ORAC (>124.566,81 ± 581,96 μg TROLOX/g) tests. Conclusions: The results presented in this study suggest that the extracts obtained from grape seeds, especially those obtained by means of microwave-assisted extraction, have a potential use in food and pharmaceutical industries, due to their high antioxidant capacity and their total phenolic compounds and flavonoids content.


Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4573
Author(s):  
Fanica Balanescu ◽  
Maria Daniela Ionica Mihaila ◽  
Geta Cârâc ◽  
Bianca Furdui ◽  
Costel Vînătoru ◽  
...  

Basil (Ocimum spp.) is a traditional herbal medicine abundant in antioxidants such as phenolic compounds. As part of a diet, this herb is proved to have some roles in decreasing the risk of cancer, and in the treatment of inflammation and neurodegenerative diseases. This study aims to explore the total phenolic and flavonoid content of two new basil hybrids growing in Romania, namely “Aromat de Buzau” (AB) and “Macedon” (MB). The antioxidant capacity of those two species was also analyzed by DPPH and cyclic voltammetry. Six different flavonoids, such as catechin (+), rutin, hyperoside, naringin, naringenin, and genistein, were separated, identified, and quantified by HPLC–DAD chromatography, for the first time, from romanian basil hybrids. The main flavonoid of the extracts was found to be naringin which is present in the highest amount (26.18 mg/kg) in “Aromat de Buzau” (O. basilicum) methanolic extract. These results suggest that dietary intake of these new hybrids can be a source of antioxidant compounds.


2015 ◽  
Vol 29 (2) ◽  
pp. 231-237 ◽  
Author(s):  
Jana Šic Žlabur ◽  
Sandra Voća ◽  
Nadica Dobričević ◽  
Mladen Brnčić ◽  
Filip Dujmić ◽  
...  

Abstract 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 (100°C/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°C.


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