Pulsed Electrical Technologies Assisted Polyphenols Extraction from Agricultural Plants and Bioresources: A Review

The application of pulsed electrical technologies such as high voltage electrical discharges (HVED) and pulsed electric fields (PEF) have been currently proposed for promoting biocompounds extraction. Even if their principles of action are different, both of these techniques have shown to be efficient for the enhancement of polyphenols extraction from different raw materials as compared to control extraction. Depending on the product, the energy consumption, the cell disruption, the polyphenols composition, the extraction and purification steps are different when applying PEF or HVED. This paper thus reviews the current status of research on the application of HVED and PEF for extraction and purification of polyphenols from plants

Ultrasound enhanced aqueous extraction from rapeseed green biomass for polyphenol and protein valorization

AbstractThe objective of this study was to investigate the effects of ultrasound-enhanced aqueous extraction on the valorization of polyphenols and proteins from rapeseed green biomass. Two types of biomass were studied: mature rapeseed stems collected around the time of seed harvest, and immature rapeseed stems used as a cover crop. Response Surface Methodology (RSM) was employed for obtaining optimal extraction conditions: ultrasound power of 400 W, treatment time of 50 min, sample length of 0.5 cm and agitation speed of 250 rpm. Compared to mature rapeseed stems, immature rapeseed stems require shorter treatment time (30 vs. 50 min), and exhibit higher extraction yield of polyphenols (100 vs. 86%) and proteins (18 vs. 11%) due to their less fibrous structures. These promising findings are opening doors to a potential market for rapeseed stems as a renewable biomass

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

Opuntia stricta Haw. is considered as one of the most common cactus plant growing in Tunisia. Extracting valuable compounds from its fruit peel, considered as by-product, is drawing more and more attention, making it on the verge of commercialization. Water-soluble polysaccharides were extracted from Opuntia stricta Haw. peels, and their chemical composition assessed using thin layer chromatography. The antioxidant activities of the extracted polysaccharides were assessed using 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity, total antioxidant activity and reducing power capacity. The extraction yield of water-soluble polysaccharides was 7.53±0.86%. The chemical composition revealed the presence of rhamnose, arabinose, glucose, mannose, galactose and galacturonic acid. The infra-red spectroscopic analysis showed a similar structure to that of Opuntia ficus-indica polysaccharide peels. Additionally, the extracted polysaccharides exhibited high antioxidant activities. In fact, the free radical scavenging activity (half inhibition concentration = 6.5 mg ml-1 with 94.9% inhibition at 50 mg ml-1), the total antioxidant activity (100 μg ascorbic acid equivalent at 50 mg polysaccharides) and the reducing power capacity (absorbance 700 nm = 0.7 at 50 mg ml-1), appeared to be interesting compared to natural and synthetic antioxidants. Therefore, water-soluble polysaccharides from Opuntia stricta Haw. fruit peels could be a natural alternative to replace synthetic antioxidants

Vers l'intensification du pressage industriel des agroressources par champs électriques pulsés (étude multi-échelles)

COMPIEGNE-BU (601592101) / SudocSudocFranceF

Isolation and characterization of lignin from Moroccan sugar cane bagasse: Production of lignin-phenol-formaldehyde wood adhesive

International audiencelignin-based materials were isolated from Moroccan sugar cane bagasse after alkaline delignification. Sugar cane bagasse was subjected to hot water (70 degrees C) and alkaline aqueous solutions (15% of sodium hydroxide (NaOH), 98 degrees C) treatments. The dissolved lignin macromolecules were separated and purified. The isolated solid was then characterized by different complementary analysis (FT-IR; H-1, C-13 NMR; GPC and TGA). In the present work, the possibility of preparing wood adhesives from bagasse lignin has been explored. The results showed that the delignification with 15% NaOH resulted in yields of cellulose and lignin of 42 +/- 2.2% and 13 +/- 1.5%, respectively. The extracted lignin scaffolds exhibits high reactivity due to the high content of hydroxyl group. Their higher molecular weight (2781 g/mol) and good thermal stability (180 degrees C) make them excellent candidates for partial substitution of phenol formaldehyde (PF) resin. A resin formulation in which up to 30% of PP can be substituted by bagasse lignin gave good results and was employed for the elaboration of plywood panels which passed relevant international standard specifications for interior-grade panels

Effect of Electrofiltration on the Dewatering Kinetics of <i>Arthrospira platensis</i> and Biocompound Recovery

Arthrospira platensis (A. platensis) is a microalga with a wide range of commercial uses. One of the main concerns that needs to be addressed in microalgae biorefineries is the costs associated with the harvesting and concentration steps. Filtration has been shown to be an effective technique for concentrating microalgae and recent studies have attempted to enhance membrane filtration by applying an external electric field to the filtration cell. This study consisted of assessing the use of electrically assisted filtration (electrofiltration) at 60 A/m2 and 1 bar for the dewatering of A. platensis, as well as the effect of pretreating the microalgae with ultrasounds (US) on the filtration process. Untreated A. platensis exhibited better filtration kinetics than US-treated A. platensis, and electrofiltration was found to increase the cake dryness. More protein and pigments were present in the US-treated microalgae solution compared to the untreated microalgae, which led to the presence of higher concentrations of protein and pigments in the filtrate streams after pressure filtration at 1 bar without the application of an external electric field. Electrofiltration was found to consume less energy compared to traditional drying techniques used for A. platensis. However, electrofiltration degrades the biocompounds present in the filtrate and cake due to pH changes and other electrophoresis phenomena, which shows the need to optimize the process in future work

Application of high-voltage electrical discharges and high-pressure homogenization for recovery of intracellular compounds from microalgae Parachlorella kessleri

International audienc

Effects of Pulsed Electric Field Treatment on Compression Properties and Solutes Diffusion Behaviors of <i>Jerusalem artichoke</i>

Jerusalem artichoke is widely used as raw material for industrial production of inulin. Pressing (compression) and diffusion are two effective technologies for bio-compounds&#8217; recovery from plants. In this work, pulsed electric field (PEF) treatment at 400, 600, and 800 V/cm during 100 ms was applied to facilitate juice and solutes recovery from Jerusalem artichoke. The application of PEF led to electroporation of cell membranes and enhanced the tissue compression/juice expression and solutes diffusion. The consolidation coefficient (calculated by application of semi-empirical model) of PEF treated sample at 800 V/cm was 6.50 &#215; 10&#8722;7 m2/s, which is significantly higher than that of untreated sample (5.02 &#215; 10&#8722;9 m2/s) and close to that of freeze-thawed sample. Diffusion experiments with PEF treated samples were carried out at 25, 50, and 75 &#176;C. A PEF treatment of Jerusalem artichoke at 800 V/cm led to a similar diffusion behavior at 25 &#176;C, compared to diffusion behavior obtained from untreated sample at 75 &#176;C