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Exploitation of Natural Antioxidants: Isolation and Purification Techniques II

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Natural Products Chemistry".

Deadline for manuscript submissions: closed (31 October 2021) | Viewed by 10574

Special Issue Editor


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Guest Editor
National Technical University of Athens, Athens, Greece
Interests: antioxidants; polyphenols; extraction techniques; analysis
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

In recent decades, natural antioxidants have been broadly investigated, and numerous articles have been published on their isolation from vegetables, cereals, seeds, aromatic herbs, and several agro-industrial by-products. Both the food and the cosmetic industries are highly interested in the application of natural antioxidants in their products due to consumer preference for “natural” rather than “synthetic” additives. Moreover, terms like “polyphenols” and “bioflavonoids” are very appealing to consumers, as they have been related to health effects and anti-aging attributes. Although extensive data can be found in the literature about natural antioxidants encountered in vegetable and animal sources, few published works deal with extraction and purification methods. The development of appropriate isolation and purification techniques is indispensable for the industrial exploitation of natural antioxidants. Because of the wide interest in the first edition of the Molecules Special Issue “Exploitation of Natural Antioxidants: Isolation and Purification Techniques”, we announce the second edition of this Special Issue, “Exploitation of Natural Antioxidants: Isolation and Purification Techniques II”. This Special Issue welcomes original papers and comprehensive reviews focused on, but not limited to, isolation/extraction methods or purification techniques of raw extracts.

Prof. Dr. Vassiliki Oreopoulou
Guest Editor

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Keywords

  • natural antioxidants
  • isolation
  • extraction
  • purification
  • exploitation

Published Papers (3 papers)

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Research

21 pages, 3084 KiB  
Article
Identification and Capture of Phenolic Compounds from a Rapeseed Meal Protein Isolate Production Process By-Product by Macroporous Resin and Valorization Their Antioxidant Properties
by Tuong Thi Le, Xavier Framboisier, Arnaud Aymes, Armelle Ropars, Jean-Pol Frippiat and Romain Kapel
Molecules 2021, 26(19), 5853; https://doi.org/10.3390/molecules26195853 - 27 Sep 2021
Cited by 6 | Viewed by 2307
Abstract
In this study, phenolic compounds from an aqueous protein by-product from rapeseed meal (RSM) were identified by HPLC-DAD and HPLC-ESI-MS, including sinapine, sinapic acid, sinapoyl glucose, and 1,2-di-sinapoyl gentibiose. The main phenolic compound in this by-product was sinapine. We also performed acid hydrolysis [...] Read more.
In this study, phenolic compounds from an aqueous protein by-product from rapeseed meal (RSM) were identified by HPLC-DAD and HPLC-ESI-MS, including sinapine, sinapic acid, sinapoyl glucose, and 1,2-di-sinapoyl gentibiose. The main phenolic compound in this by-product was sinapine. We also performed acid hydrolysis to convert sinapine, and sinapic acid derivatives present in the permeate, to sinapic acid. The adsorption of phenolic compounds was investigated using five macroporous resins, including XAD4, XAD7, XAD16, XAD1180, and HP20. Among them, XAD16 showed the highest total phenolic contents adsorption capacities. The adsorption behavior of phenolic compounds was described by pseudo-second-order and Langmuir models. Moreover, thermodynamics tests demonstrated that the adsorption process of phenolic compounds was exothermic and spontaneous. The highest desorption ratio was obtained with 30% (v/v) and 70% (v/v) ethanol for sinapine and sinapic acid, respectively, with a desorption ratio of 63.19 ± 0.03% and 94.68 ± 0.013%. DPPH and ABTS tests revealed that the antioxidant activity of the hydrolyzed fraction was higher than the non-hydrolyzed fraction and higher than the one of vitamin C. Antioxidant tests demonstrated that these phenolic compounds could be used as natural antioxidants, which can be applied in the food industry. Full article
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18 pages, 1182 KiB  
Article
Novel Processes for the Extraction of Phenolic Compounds from Olive Pomace and Their Protection by Encapsulation
by Sofia Chanioti, Maria Katsouli and Constantina Tzia
Molecules 2021, 26(6), 1781; https://doi.org/10.3390/molecules26061781 - 22 Mar 2021
Cited by 52 | Viewed by 3718
Abstract
Olive pomace, the solid by-product derived from olive oil production consists of a high concentration of bioactive compounds with antioxidant activity, such as phenolic compounds, and their recovery by applying innovative techniques is a great opportunity and challenge for the olive oil industry. [...] Read more.
Olive pomace, the solid by-product derived from olive oil production consists of a high concentration of bioactive compounds with antioxidant activity, such as phenolic compounds, and their recovery by applying innovative techniques is a great opportunity and challenge for the olive oil industry. This study aimed to point out a new approach for the integrated valorization of olive pomace by extracting the phenolic compounds and protecting them by encapsulation or incorporation in nanoemulsions. Innovative assisted extraction methods were evaluated such as microwave (MAE), homogenization (HAE), ultrasound (UAE), and high hydrostatic pressure (HHPAE) using various solvent systems including ethanol, methanol, and natural deep eutectic solvents (NADESs). The best extraction efficiency of phenolic compounds was achieved by using NADES as extraction solvent and in particular the mixture choline chloride-caffeic acid (CCA) and choline chloride-lactic acid (CLA); by HAE at 60 °C/12,000 rpm and UAE at 60 °C, the total phenolic content (TPC) of extracts was 34.08 mg gallic acid (GA)/g dw and 20.14 mg GA/g dw for CCA, and by MAE at 60 °C and HHPAE at 600 MPa/10 min, the TPC was 29.57 mg GA/g dw and 25.96 mg GA/g dw for CLA. HAE proved to be the best method for the extraction of phenolic compounds from olive pomace. Microencapsulation and nanoemulsion formulations were also reviewed for the protection of the phenolic compounds extracted from olive pomace. Both encapsulation techniques exhibited satisfactory results in terms of encapsulation stability. Thus, they can be proposed as an excellent technique to incorporate phenolic compounds into food products in order to enhance both their antioxidative stability and nutritional value. Full article
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20 pages, 1036 KiB  
Article
Bioactive Phenolic Compounds from Primula veris L.: Influence of the Extraction Conditions and Purification
by Maria Tarapatskyy, Aleksandra Gumienna, Patrycja Sowa, Ireneusz Kapusta and Czesław Puchalski
Molecules 2021, 26(4), 997; https://doi.org/10.3390/molecules26040997 - 13 Feb 2021
Cited by 18 | Viewed by 3965
Abstract
Our experiments may help to answer the question of whether cowslip (Primula veris L.) is a rich source of bioactive substances that can be obtained by efficient extraction with potential use as a food additive. A hypothesis assumed that the type of [...] Read more.
Our experiments may help to answer the question of whether cowslip (Primula veris L.) is a rich source of bioactive substances that can be obtained by efficient extraction with potential use as a food additive. A hypothesis assumed that the type of solvent used for plant extraction and the individual morphological parts of Primula veris L. used for the preparation of herbal extracts will have key impacts on the efficiency of the extraction of bioactive compounds, and thus, the health-promoting quality of plant concentrates produced. Most analysis of such polyphenolic compound contents in extracts from Primula veris L. has been performed by using chromatography methods such as ultra-performance reverse-phase liquid chromatography (UPLC−PDA−MS/MS). Experiments demonstrated that the most effective extraction agent for fresh study material was water at 100 °C, whereas for dried material it was 70% ethanol. The richest sources of polyphenolic compounds were found in cowslip primrose flowers and leaves. The aqueous and ethanol extracts from Primula veris L. were characterized by a quantitatively rich profile of polyphenolic substances, and a high antioxidative potential. Selective extraction with the use of mild conditions and neutral solvents is the first step to obtaining preparations from cowslip primrose with a high content of bioactive substances. Full article
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