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Open AccessArticle

Polyphenols from Red Vine Leaves Using Alternative Processing Techniques

Chair of Separation Science and Technology, TU Kaiserslautern, 67663 Kaiserslautern, Germany
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Processes 2018, 6(12), 262; https://doi.org/10.3390/pr6120262
Received: 31 October 2018 / Revised: 30 November 2018 / Accepted: 10 December 2018 / Published: 12 December 2018
(This article belongs to the Special Issue Microwave Applications in Chemical Engineering)
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Abstract

The extraction kinetics of polyphenols, which are leached from red vine leaves, are studied and evaluated using a laboratory robot and nonconventional processing techniques such as ultrasonic (US)-, microwave (MW)-, and pulsed electric field (PEF)-assisted extraction processes. The robotic high-throughput screening reveals optimal extraction conditions at a pH value of 2.5, a temperature of 56 °C, and a solvent mixture of methanol:water:HCl of 50:49:1 v/v/v. Nonconventional processing techniques, such as MW- and US-assisted extraction, have the fastest kinetics and produce the highest polyphenol yield. The non-conventional techniques yield is 2.29 g/L (MW) resp. 2.47 g/L (US) for particles that range in size from 450 to 2000 µm and 2.20 g/L (MW) resp. 2.05 g/L (US) for particles that range from 2000 to 4000 µm. PEF has the lowest yield of polyphenols with 0.94 g/L (450–2000 µm), resp. 0.64 g/L (2000–4000 µm) in comparison to 1.82 g/L (2000 to 4000 µm) in a standard stirred vessel (50 °C). When undried red vine leaves (2000 to 4000 µm) are used the total phenol content is 1.44 g/L with PEF. View Full-Text
Keywords: red vine leaves; polyphenols; microwaves; ultrasonic waves; pulsed electric fields; laboratory robot; extraction red vine leaves; polyphenols; microwaves; ultrasonic waves; pulsed electric fields; laboratory robot; extraction
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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
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Bachtler, S.; Bart, H.-J. Polyphenols from Red Vine Leaves Using Alternative Processing Techniques. Processes 2018, 6, 262.

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