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SM ISO690:2012 TATAROV, Pavel, IVANOVA, Raisa, BAERLE, Alexei, SANDU, Iuliana, BRINDZA, Ján. Walnut kernels pellicle (Juglans regia l.) – a good source of gallic, ellagic acids, catechin and their derivatives for functional foods. In: Agrobiodiversity for improving the nutrition, health: , quality of life and spiritual human development, Ed. 5, 3 noiembrie 2021, Nitra. Nitra, Slovacia: Slovak University of Agriculture in Nitra, 2021, Ediția 5, p. 123. ISBN 978-80-552-2401-5. 10.15414/2021.9788055224015 |
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Agrobiodiversity for improving the nutrition, health Ediția 5, 2021 |
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Conferința "Agrobiodiversity for Improving the Nutrition, Health, Quality of Life and Spiritual Human Development" 5, Nitra, Slovacia, 3 noiembrie 2021 | |||||||
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Pag. 123-123 | |||||||
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The pellicles, which cover the walnut kernels, protect the lipids from the kernel’s |
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Cuvinte-cheie antioxidant activity, functional foods, gradient elution, HPLC, kernel’s pellicle, polyphenols |
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<?xml version='1.0' encoding='utf-8'?> <oai_dc:dc xmlns:dc='http://purl.org/dc/elements/1.1/' xmlns:oai_dc='http://www.openarchives.org/OAI/2.0/oai_dc/' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:schemaLocation='http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd'> <dc:creator>Tatarov, P.G.</dc:creator> <dc:creator>Ivanova, R.A.</dc:creator> <dc:creator>Baerle, A.V.</dc:creator> <dc:creator>Sandu, I.</dc:creator> <dc:creator>Brindza, J.</dc:creator> <dc:date>2021</dc:date> <dc:description xml:lang='en'><p>The pellicles, which cover the walnut kernels, protect the lipids from the kernel’s<br />endosperm against the oxidative degradation. In previous studies, we showed that for the<br />formation of the bad brown colour and bitter taste of walnut kernels, the oxidized polyphenols<br />(naphthoquinones) are responsible. It is necessary to mention that the ratio between the<br />average content of total polyphenols in pellicles and in kernels can reach 12.7, and this<br />excellently correlated with mass fraction of pellicle in the kernels (10–11 %). The majority<br />(more than 90 %) of phenolic compounds are concentrated in the pellicle.<br />The purpose of this research was to found the optimal extraction’s conditions of phenolic<br />compounds from kernel pellicles and to evaluate the antioxidant capacity of these. The yield of<br />extractive components was determined in function of the concentration of food-grade ethanol<br />as solvent, temperature of extraction and previous defatting procedure. Defatting was realized<br />by hydraulic pressing at 20MPa. Results showed that the maximum amounts of phenolic<br />compounds were extracted with 50 % aqueous ethanol at 22–24 °C from the pellicles, obtained<br />from native not-defatted kernels. The total polyphenol content in extract from defatted kernels<br />was of 1.2–1.4 times higher than from the native kernels. But we observed, that the<br />contamination of kernel’s pellicle with the lipids, extracted from endosperm during pressing,<br />make much more difficult extraction of phenolic compounds from the pellicle with aqueous<br />ethanol solutions. The optimization of extraction conditions gives the opportunity to obtain the<br />extracts with total phenolic content increased by 1.5–2.0 times. Due to a rich phenolic content,<br />in dry residue consisted approximately 55–60 %, these extracts exhibited pronounced<br />biological activity. HPLC analysis of polyphenols was performed at "Shimadzu LC-2030C 3DPlus"<br />with PDA detector, by gradient elution with water: acetic acid (polar phase A) and<br />acetonitrile: acetic acid (non-polar phase B), using reversed-phased C18 column "Phenomenex"<br />(150mm*4.6mm*5μm*80nm). HPLC show the presence in extracts of a high quantitates of<br />biologically active compounds: gallic acid and its derivatives, ellagic acid, casuarictin, catechin,<br />epicatechin and partially identified derivatives of rutin. Antioxidative activities of the extracts,<br />obtained from kernel’s pellicle, were determined in vitro by evaluation of peroxyl radical<br />scavenging capacity. Antioxidant activities were calculated in gallic acid equivalent (GAE) in<br />mM per gram of the dry residue. Antioxidant activities varied from 2.10 to 3.17 mM GAE/g, in<br />function of harvesting year and defatting pre-treatment.<br />To conclude, the pellicle of walnut kernels is a valuable source of the biologic active<br />phenolic compounds with antioxidative properties, which could be used for development of the<br />food compositions with functional properties. Notable fact: extraction of phenolic compounds<br />from the pellicle prevent a kernel’s browning and bittering. Use of so-called dephenolised<br />walnuts seems to be a promisingly way for the development of smart food technologies.</p></dc:description> <dc:identifier>10.15414/2021.9788055224015</dc:identifier> <dc:source>Agrobiodiversity for improving the nutrition, health (Ediția 5) 123-123</dc:source> <dc:subject>antioxidant activity</dc:subject> <dc:subject>functional foods</dc:subject> <dc:subject>gradient elution</dc:subject> <dc:subject>HPLC</dc:subject> <dc:subject>kernel’s pellicle</dc:subject> <dc:subject>polyphenols</dc:subject> <dc:title>Walnut kernels pellicle (Juglans regia l.) – a good source of gallic, ellagic acids, catechin and their derivatives for functional foods</dc:title> <dc:type>info:eu-repo/semantics/article</dc:type> </oai_dc:dc>