Green Extraction and Formulation of Antioxidants Derived from Food- and Agricultural Waste

A special issue of Antioxidants (ISSN 2076-3921). This special issue belongs to the section "Natural and Synthetic Antioxidants".

Deadline for manuscript submissions: closed (10 January 2024) | Viewed by 6305

Special Issue Editors

Department of Food Chemistry, Faculty of Pharmacy and Biochemistry, University of Zagreb, Ante Kovačića 1, 10000 Zagreb, Croatia
Interests: nutraceuticals; bioavailability; in vitro digestion; bioactive compounds; polyphenols; food waste; green extraction
Department of Food Chemistry, Faculty of Pharmacy and Biochemistry, University of Zagreb, Ante Kovačića 1, 10000 Zagreb, Croatia
Interests: nutraceuticals; bioavailability; in vitro digestion; bioactive compounds; polyphenols; food waste; green extraction

Special Issue Information

Dear Colleagues,

Food and agricultural wastes have been recognized as valuable and easily accessible sources of bioactive compounds, including different types of antioxidants. Increasing the utilization of waste as secondary raw material has been given a lot of attention recently because it is both cost-efficient and in accordance with the principles of the circular economy and sustainable nutrition.

Antioxidants are compounds known for their beneficial effects on human health and have attracted great interest as nutraceuticals to be utilized in the development of functional foods and dietary supplements. They differ significantly considering their physicochemical properties and are often characterized by low stability (e.g., oxygen, light and heat sensitivity), inadequate sensory properties, low solubility, or low bioavailability (due to poor absorption, or intensive metabolism and elimination). Those factors limit the possibilities of their utilization as nutraceuticals.

To overcome these limitations, it is necessary to develop suitable extraction and formulation procedures specifically designed for each antioxidant aiming to maintain the stability of the active ingredient and to deliver it in a suitable form to the target. The focus should be on green extraction and formulation techniques requiring less energy, non-toxic solvents and lower amounts of lipids, surfactants, and biopolymers while providing safe and superior products.

In this Special Issue, original research reports and updated literature reviews will provide the current state of the knowledge on the novel green extraction and formulation of antioxidants derived from food and agricultural wastes.

Prof. Dr. Dubravka Vitali Čepo
Dr. Kristina Radić
Guest Editors

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Published Papers (5 papers)

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Research

17 pages, 3831 KiB  
Article
The Utilization of an Aloe Vera Rind By-Product: Deep Eutectic Solvents as Eco-Friendly and Recyclable Extraction Media of Polyphenolic Compounds
Antioxidants 2024, 13(2), 162; https://doi.org/10.3390/antiox13020162 - 26 Jan 2024
Viewed by 626
Abstract
In this study, an optimized environmentally friendly procedure was employed to enhance the sustainable utilization of phenolic antioxidants derived from aloe vera rind by-products. The procedure involved the application of ultrasound-assisted extraction (UAE) in combination with deep eutectic solvents (DESs). Eleven different DESs [...] Read more.
In this study, an optimized environmentally friendly procedure was employed to enhance the sustainable utilization of phenolic antioxidants derived from aloe vera rind by-products. The procedure involved the application of ultrasound-assisted extraction (UAE) in combination with deep eutectic solvents (DESs). Eleven different DESs and three conventional solvents were employed as extraction media for polyphenolic compounds. Choline chloride–citric acid (ChCl-CA) was selected as the most suitable extractant, considering its extraction efficiency in relation to the total phenolic content. The operating conditions of UAE were optimized and modeled by the use of response surface methodology in order to maximize the yield of total phenolics and antioxidant capacity. The optimal operational parameters for the UAE procedure were determined to be 16.5 min, 74% (v/v) DES in water, and a solvent-to-solid ratio equal to 192. HPLC analysis, which was performed on the optimum extract, revealed significant levels of phenolics present in the aloe rind. Efficient recovery of the extracted antioxidants was obtained by the use of solid-phase extraction (SPE) and polyamide cartridges. The ChCl-CA DES exhibited excellent recycling capability with a yield of over 90% through SPE. Finally, the greenness of the method was evaluated using the green AGREE and AGREEprep metrics. The results highlighted the sustainability and the greenness of the proposed extraction procedure for the aloe by-product. Full article
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19 pages, 10516 KiB  
Article
Valorization of Olive Leaf Polyphenols by Green Extraction and Selective Adsorption on Biochar Derived from Grapevine Pruning Residues
Antioxidants 2024, 13(1), 1; https://doi.org/10.3390/antiox13010001 - 19 Dec 2023
Viewed by 699
Abstract
Given today’s increasingly intensive agriculture, one key problem area considers the valorization and reuse of wastes from food and agricultural production with minimal impact on the environment. Due to its physicochemical characteristics, biochar (BC) derived from grapevine pruning residue has shown considerable potential [...] Read more.
Given today’s increasingly intensive agriculture, one key problem area considers the valorization and reuse of wastes from food and agricultural production with minimal impact on the environment. Due to its physicochemical characteristics, biochar (BC) derived from grapevine pruning residue has shown considerable potential for use as an adsorbent. High-value phytochemicals found in abundance in the olive leaf (OL) can be employed in many different industrial sectors. The potential application of BC in the removal of specific polyphenolic components from OL extracts has been investigated in the present study. Water, as the most available and greenest of solvents, was investigated as to its use in the extraction of polyphenols, which was carried out by comparing maceration, ultrasound-assisted extraction, and microwave-assisted extraction, considering different temperatures and solid-to-liquid (s/l) ratios. The BC adsorption capacity of selected polyphenols was fitted with both the Langmuir and Freundlich isotherm models. The Freundlich model fitted better relative to OL polyphenols adsorption. Oleuropein was the most abundant compound identified in the extracts, obtaining the highest Kf value (20.4 (mg/g) × (L/g)n) and R2 coefficient (0.9715) in the adsorption on the biochar’s surface. The optimum conditions in the dosage experiment suggest the use of 0.5 g of BC using 3 g/L extracts, with an exception for oleuropein and hydroxytyrosol, for which the highest biochar dose (2.5 g) performed better. Considering the compounds’ concentrations and the BC dose, BC from grapevine pruning residues demonstrated a potential use in the uptake of specific polyphenols from olive leaves, making it a promising adsorbent for such applications. Full article
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18 pages, 891 KiB  
Article
Valorization of Citrus reticulata Blanco Peels to Produce Enriched Wheat Bread: Phenolic Bioaccessibility and Antioxidant Potential
Antioxidants 2023, 12(9), 1742; https://doi.org/10.3390/antiox12091742 - 08 Sep 2023
Cited by 1 | Viewed by 919
Abstract
The fortification of foods with bioactive polyphenols aims to improve their functional properties and to provide health benefits. Yet, to exert their benefits, phenolic compounds must be released from the food matrix and absorbed by the small intestine after digestion, so assessing their [...] Read more.
The fortification of foods with bioactive polyphenols aims to improve their functional properties and to provide health benefits. Yet, to exert their benefits, phenolic compounds must be released from the food matrix and absorbed by the small intestine after digestion, so assessing their bioaccessibility is crucial to determine their potential role. This work aims to incorporate Citrus reticulata Blanco peel extracts into wheat bread as a promising opportunity to increase their bioactive potential, along with supporting the sustainable management of citrus-industry waste. A control and a wheat bread enriched at 2% and 4% (w/v) with a phenolic extract from mandarin peels were prepared and analyzed for antioxidant activity and phenolic composition using LC-MS and UV-Vis spectrophotometry. In addition, in vitro digestion was performed, and the digested extracts were analyzed with HPLC-MS/MS. The results showed a significant increase in total flavonoid content (TFC, 2.2 ± 0.1 mg·g−1), antioxidant activity (IC50 = 37 ± 4 mg·g−1), and contents of quercetin, caffeic acid, and hesperidin in the 4% (w/v) enriched bread. Yet, most polyphenols were completely degraded after the in vitro digestion process, barring hesperidin (159 ± 36 μg·g−1), highlighting the contribution of citrus enrichment in the development of an enriched bread with antioxidant potential. Full article
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18 pages, 1402 KiB  
Article
Wine Lees as Source of Antioxidant Molecules: Green Extraction Procedure and Biological Activity
Antioxidants 2023, 12(3), 622; https://doi.org/10.3390/antiox12030622 - 02 Mar 2023
Cited by 5 | Viewed by 1310
Abstract
An ultrasound-assisted extraction method, employing ethanol and water as solvents at low temperature (30 °C) and reduced time (15 min), was proposed to extract bioactive molecules from different cultivars (Magliocco Canino, Magliocco Rosato, Gaglioppo, and Nocera Rosso) of [...] Read more.
An ultrasound-assisted extraction method, employing ethanol and water as solvents at low temperature (30 °C) and reduced time (15 min), was proposed to extract bioactive molecules from different cultivars (Magliocco Canino, Magliocco Rosato, Gaglioppo, and Nocera Rosso) of wine lees. All the extract yields were evaluated and their contents of phenolic acids, flavonoids, and total polyphenols were determined by means of colorimetric assays and high-performance liquid chromatography coupled with diode-array detection (HPLC-DAD) and Fourier transform infrared (FTIR) techniques. Radical scavenging assays were performed and the Magliocco Canino extracted with a hydroalcoholic mixture returned the best results both against ABTS (0.451 mg mL−1) and DPPH (0.395 mg mL−1) radicals. The chemometric algorithms principal component analysis (PCA) and partial least square regression (PLS) were used to process the data obtained from all qualitative–quantitative sample determinations with the aim of highlighting data patterns and finding possible correlations between composition and antioxidant features of the different wine lees cultivars and the extraction procedures. Wine lees from Magliocco Canino and Magliocco Rosato were found to be the best vegetable matrices in terms of metabolite content and antioxidant properties. The components extracted with alcoholic or hydroalcoholic solvents, specifically (−)-epigallocatechin gallate, chlorogenic acid, and trans-caftaric acid, were found to be correlated with the antioxidant capacity of the extracts. Multivariate data processing was able to identify the compounds related to the antioxidant features. Two PLS models were optimized by using their concentration levels to predict the IC50 values of the extracts in terms of DPPH and ABTS with high values of correlation coefficient R2, 0.932 and 0.824, respectively, and a prediction error lower than 0.07. Finally, cellular (SH-SY5Y cells) antioxidant assays were performed on the best extract (the hydroalcoholic extract of Magliocco Canino cv) to confirm its biological performance against radical species. All these recorded data strongly outline the aptness of valorizing wine lees as a valuable source of antioxidants. Full article
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12 pages, 1087 KiB  
Article
Bioactive Compounds of Shrimp Shell Waste from Palaemon serratus and Palaemon varians from Portuguese Coast
Antioxidants 2023, 12(2), 435; https://doi.org/10.3390/antiox12020435 - 09 Feb 2023
Cited by 4 | Viewed by 1852
Abstract
The production and consumption of shrimp species create massive amounts of shrimp bio-waste. In this study, shrimp shell waste from Palaemon serratus and Palaemon varians from the Portuguese coast was characterized. Regarding the antioxidant capacity, the obtained values were between 4.7 and 10.4 [...] Read more.
The production and consumption of shrimp species create massive amounts of shrimp bio-waste. In this study, shrimp shell waste from Palaemon serratus and Palaemon varians from the Portuguese coast was characterized. Regarding the antioxidant capacity, the obtained values were between 4.7 and 10.4 mg gallic acid equivalents (GAE)/g dry weight (dw) for Total phenolic content (TPC); 3 and 7 mg ascorbic acid equivalents (AAE)/g dw for Ferric reducing antioxidant power assay (FRAP); 0.4 and 1.2 mg Trolox equivalent (TE)/g dw for 2,2-diphenyl-1-picryl-hydrazyl-hydrate free radical scavenging (DPPH); 4 and 11 mg TE/g dw for 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity (ABTS•+); and 72 and 130 mg TE/g dw for Oxygen radical absorbance capacity (ORAC). For the antimicrobial activity, shrimp shell waste from P. varians formed inhibition zones between 14 and 23 mm. Total carotenoid content values were in the range of 28 and 134 μg/g dw, and according to their HPLC-PAD profile, β-carotene and astaxanthin contents were between 0.3 and 7.6 μg/g dw and 1.1 and 26.1 μg/g dw, respectively. These studies are critical to recognizing the potential added value of shrimp shell waste as possible colorants and preservatives with antioxidant protection capacity to be used in the food industry. Full article
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