scholarly journals Is the Household Microwave Recommended to Obtain Antioxidant-Rich Extracts from Lycium barbarum Leaves?

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 656
Author(s):  
Luna Pollini ◽  
Federica Ianni ◽  
Giuseppa Verducci ◽  
Francesca Blasi ◽  
Lina Cossignani

Nowadays, much interest is devoted to the extraction of plant materials, considering also their waste and by-products, to obtain antioxidant-rich products. The effect of household microwave-assisted extraction (MAE) on the phenolic content and antioxidant activity of Lycium barbarum leaf extracts was investigated. An experimental design approach was adopted considering solid/liquid ratio (1, 3, and 5 g of leaves in 150 mL water), irradiation time (1, 3, and 5 min), and microwave power (300, 400, and 500 W) as independent variables. These three factors and their interactions were studied to evaluate the effect of MAE conditions on the responses of total phenolic content, antioxidant activity, and chlorogenic acid content. The results showed that the analytical parameters were positively influenced by the solid/liquid ratio and time. On the contrary, microwave power was inversely correlated with the investigated responses. This research revealed that microwave extraction conditions should be carefully monitored to obtain bioactive-rich aqueous extracts with high antioxidant activity. A comparison with household traditional methods showed an unexpected lower phenolic content and antioxidant activity for MAE extract in respect to the decoction and infusion. In fact, it was found that L. barbarum leaf infusion had the best functional properties, regarding the investigated characteristics. The outcome of this study has implications for raising awareness that household preparation conditions strongly affect the health properties of herbal extracts.

2017 ◽  
Vol 18 (2) ◽  
pp. 105-116 ◽  
Author(s):  
Farhan M. Said

The objective of this research was to identify the recovery of the biological active compound of Musa sp. thru microwave assisted extraction (MAE) system. Antioxidant activity and phenolic compound were investigated on the effect of temperature, microwave power, irradiation time and solid to liquid ratio. The extraction process was carried out using only distilled water as an extracting agent. The result showed that, at 70oC fresh Musa sp. extracted 45% higher antioxidant compared to the dried Musa sp. 500 W was the best power of MAE to extract antioxidant and phenolic compound of ripe Musa sp., while for unripe Musa sp. 800 W was the best. The best irradiation time was 90 s, where it extracted almost 90% antioxidant activity of ripe and unripe Musa sp. Almost 480 mg GA/100 g FW of total phenolic content was extracted on the unripe peel. Solid to liquid ratio of 3 : 60 was the best parameter to extract antioxidant and phenolic content of ripe and unripe Musa sp. Overall, antioxidant and phenolic compound were significantly higher in the unripe peel, followed by ripe peel, unripe pulp and ripe pulp.


Antioxidants ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 355 ◽  
Author(s):  
Melanie S. Matos ◽  
Rut Romero-Díez ◽  
Ana Álvarez ◽  
M. R. Bronze ◽  
Soraya Rodríguez-Rojo ◽  
...  

Phenolics present in grapes have been explored as cosmeceutical principles, due to their antioxidant activity and ability to inhibit enzymes relevant for skin ageing. The winemaking process generates large amounts of waste, and the recovery of bioactive compounds from residues and their further incorporation in cosmetics represents a promising market opportunity for wine producers and may contribute to a sustainable development of the sector. The extracts obtained from grape marc and wine lees, using solid–liquid (SL) extraction with and without microwave (MW) pretreatment of the raw material, were characterized in terms of antioxidant activity through chemical (ORAC/HOSC/HORAC) and cell-based (keratinocytes—HaCaT; fibroblasts—HFF) assays. Furthermore, their inhibitory capacity towards specific enzymes involved in skin ageing (elastase; MMP-1; tyrosinase) was evaluated. The total phenolic and anthocyanin contents were determined by colorimetric assays, and HPLC–DAD–MS/MS was performed to identify the main compounds. The MW pretreatment prior to conventional SL extraction led to overall better outcomes. The red wine lees extracts presented the highest phenolic content (3 to 6-fold higher than grape marc extracts) and exhibited the highest antioxidant capacity, being also the most effective inhibitors of elastase, MMP-1 and tyrosinase. The results support that winemaking waste streams are valuable sources of natural ingredients with the potential for cosmeceutical applications.


Beverages ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 2
Author(s):  
Quang Vinh Nguyen ◽  
Hoang Van Chuyen

Roselle (Hibiscus sabdariffa L.) is an annual shrub popularly grown in tropical and subtropical areas. Although Roselle fruit has been used for a long time as a herbal tea due to its high content of bioactive compounds like phenolic acids and anthocyanins, the studies on the effects of the drying process and brewing conditions on the content of beneficial components and bioactivities of Roselle tea is limited. In this study, the influence of drying temperature on the retention of total phenolic content (TPC) and antioxidant capacity (AC) of the dried Roselle and the effects of brewing conditions including water temperature, liquid-solid ratio and brewing time on total soluble solid (TSS) content, total phenolic content, and antioxidant capacity of Roselle tea were investigated. The drying at 80 °C produced the dried Roselle with the highest retention of TPC (25.196 mg GAE/g) and AC (IC50 of 2.2 mg/mL for 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition) and the highest sensory quality compared to the drying at other temperatures. The brewing process using hot water at 90 °C with the solid-liquid ratio of 1:10 (g/mL) for 30 min resulted in the highest TSS content (5.4 oBx), TPC (12.7 mg GAE/g dried Roselle) and AC (73.3% DPPH inhibition) of the Roselle tea. Thus, the drying at 80 °C combined with the brewing of dried Roselle for 30 min using 90 °C hot water with the solid-liquid ratio of 1:10 (g/mL) are recommended to produce Roselle tea with the highest content of beneficial ingredients.


Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5891
Author(s):  
Rocío Maceiras ◽  
Víctor Alfonsín ◽  
Luis Seguí ◽  
Juan F. González

Biomass pretreatment has an important role in the production of cellulosic bioethanol. In this study, the effectiveness of microwave assisted alkaline pretreatment of algae waste was analysed. After pretreatment, the product was hydrolysed using sulphuric acid. The effects of microwave power, irradiating time, solid–liquid ratio and NaOH concentration were examined. Under the best conditions, the fermentable sugars were converted to cellulosic bioethanol using Saccharomyces Cerevisiae with a bioethanol yield of 1.93 ± 0.01 g/g and a fermentation efficiency of 40.4%. The reducing sugars concentration was 30% higher than that obtained from conventional hydrolysis without pretreatment. The obtained results suggest that microwave assisted alkaline pretreatment is effective in improving the production of cellulosic bioethanol of algae waste compared to that without microwave effect. Considering energy consumption, low microwave power and short microwave irradiation time are favourable for this pretreatment.


Antioxidants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 322 ◽  
Author(s):  
Mircea Oroian ◽  
Florin Ursachi ◽  
Florina Dranca

The aim of this study was to evaluate the extraction efficiency of polyphenols from crude pollen by an ultrasonic process. Prior to the polyphenols extraction, the crude pollen was defatted. The extraction from defatted pollen was carried out by varying four extraction parameters: ultrasonic amplitude (20%, 60% and 100%), solid/liquid ratio (10 g/L, 20 g/L and 30 g/L), temperature (35, 50 and 65 °C) and time (10, 20 and 30 min). The extracts were analyzed in terms of extraction yield (%), total phenolic content (TPC) and total flavones content (TFC). The extracted oil was analyzed in terms of fatty acids composition; myristic acid (159.1 µg × g−1) and cis-14-pentadecenoic acid (106.6 µg·g−1) were found in the highest amount in the pollen oil. The optimum conditions of extraction were determined and were, as follows: 100% amplitude of ultrasonic treatment, 30 g/L solid/liquid ratio, 40.85 °C and 14.30 min, which led to the extraction of 366.1 mg GAE/L of TPC and 592.2 mg QE/g of TFC, and also to an extraction yield of 1.92%.


2021 ◽  
Vol 4 ◽  
pp. 46
Author(s):  
Theophilus Fadjare Frempong ◽  
Nathaniel Owusu Boadi ◽  
Mercy Badu

Background: The recovery of phenolic compounds is seen as an arduous task because phenolic compounds are available as free aglycones, as sugar or ester conjugates, or as polymers with several monomeric components. Furthermore, phenolic compounds do not disperse evenly and may be connected to cell walls, carbohydrates, or proteins. This study looks at the optimization of factors that affect the efficiency for the extraction of phenolic compounds from the stem-bark of Funtumia elastica. Methods: Five independent variables (solvent concentration, time, the temperature, solid-liquid ratio, and pH) of the extraction process were selected. Single factor analysis as well as the response surface method was used to evaluate the impact of the selected factors on the total phenolic content. The effect of the extraction factors on the phenolic content was statistically significant (p <0.05). For the response surface method, a five/factor, five/level central composite design used, and a fitted second-order polynomial regression model equation was used to show how the extraction parameters affected the total phenolic recovery. Results: The predicted value (R² of 0.5917) agreed with the adjusted value (R² of 0.7707). The residuals for response predictions were less than 5%. The optimal factors for the extraction were ethanol concentration of 75.99% v/v, extraction time of 193.86 minutes, temperature of 63.66°C, pH of 5.62, and solid-liquid ratio of 1:21.12 g/mL. Actual overall content of the phenolic compounds was validated at 82.83 ± 3.335 mg gallic acid equivalent (GAE) /g weight of extract, which agreed with the predicted response of 89.467 mg GAE/g of the dried extract under the optimal factors. Conclusions: The rich phenolic content of stem-bark of Funtumia elastica points to its potential as a functional medicinal product to alleviate diseases caused by oxidative stress such as asthma, breathing disorders, inflammation, and cardiovascular diseases.


2021 ◽  
Author(s):  
Z. Ait lhaj ◽  
K. Taghzouti ◽  
A. Bouyahya ◽  
G. Diria ◽  
K. Bakhy ◽  
...  

This study was aimed at determining the phenolic composition and the antioxidant activity of leaves of Arbutus unedo populations belonging to seven Moroccan locations. Antioxidant activity is evaluated using two methods: scavenging effect on DPPH and scavenging effect on ABTS radicals. The Arbutus unedo leaf extracts displayed average values of 61.95 mg GAE, 3.60 mg QE, and 0.15 mg CE per g of dry weight (DW) in polyphenols, flavonoids, and tannins contents, respectively. All extracts exhibited a strong antioxidant effect on both assays, presenting mean IC50 values of 4.22 in DPPH assay and 4.86 μg/ml in ABTS assay. Significant variability (P < 0.0001) was showed among surveyed populations; samples from the Chefchaouen location (CH) was revealed the highest total phenolic content (107.67 mg GAE/g DW) and the strongest antioxidant activity (IC50 values of 0.80 and 1.56 μg/ml, in DPPH and ABTS tests, respectively). The phenolic profile achieved by HPLC-DAD-ESI/MS was dominated by gallic acid, Gallic acid glucose derivative, and Galloylquinic acid derivative. A significant negative correlation (P < 0.05) was observed between the total phenolic content and the antioxidant activity. These results provide that Arbutus unedo leaves should be considered as a promising source of natural antioxidants, and as ingredients in complimentary food and nutraceutical products.


2009 ◽  
Vol 4 (6) ◽  
pp. 1934578X0900400 ◽  
Author(s):  
Mahassine Amensour ◽  
Esther Sendra ◽  
Jamal Abrini ◽  
Samira Bouhdid ◽  
José Angel Pérez-Alvarez ◽  
...  

The total phenolic content and antioxidant activity of methanolic, ethanolic and aqueous extracts of myrtle ( Myrtus communis) leaves and berries were measured to find new potential sources of natural antioxidants. Total phenolic content was assessed by the Folin-Ciocalteau assay, while the antioxidant activity was evaluated by three methods: diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay, the reducing antioxidant power assay and β-carotene linoleic acid assay. The total phenol content of myrtle extracts ranged between 9.0 and 35.6 mg GAE per g extract. For each solvent, leaf extracts contained significantly higher amount of total phenolic compounds than berry extracts. All of the extracts presented antioxidant capacity assessed by the three methods, but at different levels depending on the concentration, the extraction solvent and the part of the plant used. Generally, leaf extracts showed higher antioxidant activities than berry extracts, while the overall antioxidant strength was in the order methanol > water > ethanol in leaf extracts and methanol > ethanol >water in berry extracts. The phenolic content exhibited a positive correlation with the antioxidant activity: DPPH assay showed the highest correlation (r = 0.949), followed by the reducing power assay (r = 0.914) and the lowest for the β-carotene linoleic acid assay (r = 0.722).


Poljoprivreda ◽  
2020 ◽  
Vol 26 (2) ◽  
pp. 3-10
Author(s):  
Daniela Horvat ◽  
◽  
Marijana Tucak ◽  
Marija Viljevac Vuletić ◽  
Tihomir Čupić ◽  
...  

The leaf samples of two varieties, twenty breeding populations, and seven local populations of the Croatian red clover were collected in the full flowering stage, with an aim to evaluate their phenolic content and antioxidant activity by using the spectrophotometric methods. A significant variation among the varieties/populations in the content of total phenolics and flavonoids was determined. The results demonstrated that the red clover is a rich source of phenolics and flavonoids, ranging from 38.67 to 59.96 mg GAE/g of DM and 21.19 to 51.48 mg CE/g of DM, respectively. The high levels in both phenolics and flavonoids were found in breeding populations/variety CD-8, Rc-11/7, Rc-11/8, Rc-11/15 and OS Osiris. The leaf extracts manifested a strong antioxidant activity towards diphenyl-1-picrylhydrazyl (DPPH), with a variation from 31.50 to 63.14%. A significant correlation was found between the antioxidant activity of the extracts and their total phenolic and flavonoid content (r = 0.737 and 0.839, respectively). Considering the obtained results, the crude extracts of red clover manifested a significant antioxidant potential and can be used as a natural source of biologically active components in the human and animal nutrition.


Sign in / Sign up

Export Citation Format

Share Document