Phenols and Antioxidant Activity in Vitro and in Vivo of Aqueous Extracts Obtained by Ultrasound-Assisted Extraction from Artichoke By-Products (original) (raw)
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Antioxidants
The accurate quantification of phenolic compounds (PCs) in foods has become mandatory for a reliable estimation of PCs dietary intake. However, the extraction step of these molecules from the food matrix is a challenging and complex task. To manage the current lack of an official or generally accepted procedure for the recovery of phenolics, the application of statistical and mathematical tools, such as the response surface methodology (RSM), that allow the optimization of extraction parameters and the acquisition of the best output, has become the analytical approach of choice. The aim of this study was to apply an RSM-optimized ultrasound-assisted procedure to extract phenolic compounds from artichoke (Cynara cardunculus L. var. scolymus (L.) Hegi, cultivar “Campagnano”) heads. The effect of extraction time, temperature, and solvent-to-sample ratio on the profile and content of phenolic acids and flavonoids was investigated. The total phenolic content was 488.13 ± 0.56 mg GAE 100 ...
Ultrasound-assisted Extraction of Polyphenols from Red-grape (Vitis vinifera) Residues
Red-grape (Vitis vinifera) residues contain large amounts of polyphenols, especially anthocyanins which act as antioxidants. Red-grape seeds and peel were separated from the pulp and exposed to pre-treatments with ultrasound at 35kHz over 15, 30, 45, 60, 75 y 90min as an alternative to improve the level of polyphenols extraction. Right after the pre-treatment with ultrasound, samples were subjected to an extraction operation by methanol/water (96% v/v) at 60°C over 90min, according to similar conditions previously optimized by . Both total extractive yield (dry basis) and total polyphenols content were determined for all the extracts obtained from the treated samples, and compared against an extract obtained from a non treated sample. Results showed that at the studied frequency (35kHz), there is a significant effect (α=0.05) of the ultrasound exposure time on both total extractive yield and total polyphenols content. When compared to non treated samples, the exposure to ultrasound at 45min and above showed to significantly (α=0.05) improve the extraction operation by increasing in more than 25% the total extractive yield, except at 75min. Results also showed that ultrasound exposure of the samples at 45, 75 and 90min significantly increased (α=0.05) the total polyphenols content of the extracts in about 65, 50 and 140%, respectively. The effect of ultrasound on the antioxidant capacity of the extracts was also evaluated. Results indicated that ultrasound at 35 kHz decreases the antioxidant capacity of the extracts in about 50%.
Ultrasonics Sonochemistry, 2010
Apple pomace, a by-product of the cider production, has been studied as a potential source of polyphenols, compounds of great interest for the industry. Ultrasound has been used to improve extraction efficiency in terms of time needed and total polyphenol content. A preliminary study has been first investigated to optimize ethanol proportion of aqueous extractant (50%, v/v) and solid/liquid ratio (<15%, w/v). A response surface methodology has then been used to maximize total polyphenol content of extracts and investigate influence of parameters involved in extraction procedures for both total polyphenols content and composition of extracts. Optimal settings reached from a central composite design were applied for ultrasound-assisted extraction and were compared to conventional procedure: yields were increased by more than 20%. Ultrasound-assisted polyphenols extraction from apple pomace appears to be a relevant, rapid, sustainable alternative to conventional procedure, and that scale up of the process is possible.
Green processing and synthesis, 2024
The research investigates the extraction of antioxidant phenolic compounds from grape pomace, a wine fermentation byproduct. Ultrasound-assisted extraction (UAE), varying parameters such as solute:solvent ratio, power, and time were utilized. UAE was specifically applied to Vitis vinifera L. using high-intensity ultrasound with ratios of 1:18 and 1:42 g:mL, 250 and 400 W power levels, and extraction times of 15 and 20 minutes. Total phenolic content was quantified via the Folin-Ciocalteau reagent, and total flavonoids were determined using quercetin as a standard. Antioxidant capacity was evaluated through ABTS, FRAP, and DPPH Radical Scavenging Assays, with Trolox equivalent antioxidant capacity (TEAC) for comparison. Results indicated a total phenolic content of 50 to 80 μmol GAE/g d.w., with no significant differences among treatments. Total flavonoid concentration ranged from 2.5 to 4 μmol QE/g d.w. Importantly, the solute:solvent ratio impacted antioxidant capacity, with higher ratios showing increased ABTS radical capacity. Treatment 1, with the highest flavonoid content, exhibited the greatest antioxidant capacity against DPPH radicals. This study underscores the intrinsic correlation between cumulative bioactive compound content and the inherent antioxidant capacity of grape pomace extracts. This highlights the potential application of these extracts as antioxidant reservoirs, poised for integration into functional foods and biomedical nutraceuticals.
Applied Sciences
This study investigated the use of eco-friendly novel formulations of deep eutectic solvents (DESs) with water in ultrasound-assisted extraction (UAE) of antioxidant compounds from six spices, comparing them to traditional ethanol-based solvents. Significant differences in antioxidant capacity (AC) determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP) assays, and total phenolic content (TPC) analysed using Folin-Ciocalteu (F-C) method were observed among the prepared extracts of spices. Regardless of the solvent used, clove extracts exhibited the highest antioxidant properties, whereas coriander presented the lowest values of AC and TPC. Choline chloride (ChCl)-based DES3 with propylene glycol (PG) as the hydrogen bond donor was more promising for effectively extracting antioxidants from the studied spices than ChCl-based DES1 and DES2 containing urea (U) and glycerol (Gly), respect...
Ultrasonically assisted antioxidant extraction from grape stalks and olive leaves
Physics Procedia, 2010
Grape stalks and olive leaves present high amount of phenolic compounds with antioxidant properties. The extraction of these compounds may be considered a way to increase in value both agro-food by-products. Ultrasound is widely applied in extraction due to its effects (cavitation, microstirring or sponge effect) over the process. The goal of this work was to address the application of ultrasound on the antioxidant extraction of olive leaves and grape stalk. For that purpose, the extraction of antioxidant compounds from grape stalks and olive leaves, previously dried at 100 ºC, were carried out using a ethanolic solution (80 % v/v) at 60 ºC. Extractions were carried out with (US; 30 kHz; 600W)) and agitation (AG) without ultrasound application. In the AG experiments, the solution was agitated with a stirrer. Samples were obtained at different extraction time (10, 30, 60, 120, 180, 240, 360, 480 and 1440 min) and their antioxidant capacity was measured using FRAP method. The Naik model was used to model the extraction kinetics, being identified the antioxidant capacity of extracts at the equilibrium (Y eq ) and the initial velocity of extraction (Y eq /B). For grape stalks, the antioxidant capacity of extracts at the equilibrium (Y eq ) and the initial velocity of extraction (Y eq /B) were higher in AG experiments than in US experiments. In the olive leaves extractions, the Y eq /B was of the same order for both treatments but Y eq was significantly higher for US experiments. The different influence of ultrasound for both by-products can be explained from their different geometry and structure.
Antioxidant Extraction from Mustard (Brassica juncea) Seed Meal Using High-Intensity Ultrasound
Brassicaceae oilseeds provide feedstocks for the biofuels industry, but value-added coproducts are necessary to supply financial incentives for increased production. Our objective was to use high-intensity ultrasound to optimize extraction of antioxidants from mustard (Brassica juncea) seed meal. The ultrasound-assisted extraction (UAE) variables included temperature, solvent-to-material ratio, sonication duration, and EtOH concentration. Extracts were analyzed for total phenolics content (TPC), antioxidant activity, and sinapine content. Conventional extraction using water and 70% EtOH (v/v) at 80 • C for 3×30 min yielded 7.83 ± 0.07 and 8.81 ± 0.17 mg sinapic acid equivalents (SAE)/g meal, respectively. UAE extraction at 40 • C for 30 min yielded similar phenolics content (8.85 ± 0.33 mg SAE/g meal) as conventional hot ethanolic extraction, but required less time and lower temperature. The highest TPC (13.79 ± 0.38 mg SAE/g meal) was in the 7-d aqueous extracts. Sonicated solutions of pure sinapine and sinapic acid showed 1st-order reaction kinetics with greater degradation of isolated compounds than those present in extracts. Sinapine contained in extracts showed insignificant (P < 0.05) degradation after 30 min of sonication. Our research indicates that ultrasound treatment can assist the extraction of antioxidants from B. juncea meal by reducing both the temperature and time requirement without significant degradation of the primary antioxidants present.
Acta Chimica Slovenica, 2015
The aim of the study was to evaluate the efficiency of an ultrasonic pretreatment at different amplitudes and extraction times, on the content of antioxidant compounds (phenolics, anthocyanins, ascorbic acid) and total antioxidant capacity of black currant fruits. Additionally, the influence of sample preparation (frozen storage/drying) was evaluated. Extraction was performed in 60% ethanol with 0.15% HCl at a solvent-to-sample ratio of 15/1. Our results show that the ultrasonic pretreatment proved particularly useful for the recovery of high amounts of total anthocyanins in freeze-dried samples, ascorbic acid in frozen and oven air-dried samples, and total antioxidant capacity in freeze-dried and oven airdried samples. The total phenolics content was not significantly influenced by the ultrasonic pretreatment. Freeze-drying increased the content of targeted compounds, to a very high significant level (p<0.001) for anthocyanins and ascorbic acid. Oven air-drying at 45 °C drastically decreased the ascorbic acid content. Ultrasonication enhanced the extraction yield of black currant valuable compounds in strong relation to the operating conditions.