Extraction and Stabilization of Natural Antioxidants from Agri-Food By-Products

A special issue of Antioxidants (ISSN 2076-3921). This special issue belongs to the section "Extraction and Industrial Applications of Antioxidants".

Deadline for manuscript submissions: 30 June 2024 | Viewed by 1652

Special Issue Editors

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Guest Editor
Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy
Interests: natural antioxidants; valorization of food by-products; development of functional foods and nutraceuticals; micro- and nano-encapsulation of bioactive molecules; effect of processing of food bioactive compounds
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Guest Editor
Department of NEUROFARBA, University of Florence, Via Ugo Schiff 6, Sesto Fiorentino, 50019 Florence, Italy
Interests: natural antioxidants; nutraceutical sciences; food chemistry; nutrition and human health; phenolic compounds; extraction and characterization of bioactive molecules
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Foods containing lipids can easily undergo oxidative degradation (autoxidation), leading to negative sensory traits (rancid flavour), loss of colour and aroma, and the production of toxic compounds. For this reason, antioxidants are used to extend the shelf life of foods and improve their quality. The evidence that synthetic antioxidants, although efficacious, are biased by toxicity has stimulated research to obtain new antioxidant formulations based on natural and safer molecules such as tocopherols, phenolic compounds and carotenoids.

Oxidation can also take place in the human body: when the production of reactive oxygen (ROS) and nitrogen (RNS) species is not balanced by relative detoxification strategies, we may face oxidative stress, which is acknowledged to play a key role in the onset of non-communicable diseases such as coronary heart disease (CHD), metabolic syndrome, type-2 diabetes, cancer, and neurodegenerative pathologies. The awareness that food might promote well-being and counteract oxidative stress has pushed scientists, technologists and companies to develop functional foods and nutraceuticals enriched with antioxidant compounds.

To satisfy this increasing need for natural antioxidants, it is possible to take advantage of the enormous stream of by-products from food agri-food supply chains that often contain considerable amounts of value-added molecules endowed with antioxidant capacity. Thus, the identification of alternative antioxidant sources from food by-products and more sustainable biomasses like microalgae and the development of innovative extraction processes, possibly based on green solvents, have been the objectives of many researchers. Due to the intrinsic fragility of antioxidant molecules, the extraction process is frequently followed by a stabilization phase, e.g., encapsulation, aiming to extend the efficacy of these compounds and improve functional properties such as their ease of manipulation and bioavailability. The latter represents a crucial point when it comes to the development of innovative nutraceutical formulations.

This Special Issue aims to further underline current developments in all fields dealing with the extraction, characterization and encapsulation of antioxidant compounds from alternative and more sustainable sources and evaluate their antioxidant capacity.

Dr. Gianni Zoccatelli
Dr. Maria Bellumori
Guest Editors

Manuscript Submission Information

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  • valorization of agri-food wastes/by-products
  • alternative sources of antioxidants
  • innovative and green extraction processes
  • natural antioxidants
  • encapsulation
  • biological activity
  • antioxidant activity
  • shelf-life studies
  • functional foods and ingredients
  • nutraceuticals

Published Papers (1 paper)

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26 pages, 4336 KiB  
Optimization, Metabolomic Analysis, Antioxidant Potential and Depigmenting Activity of Polyphenolic Compounds from Unmature Ajwa Date Seeds (Phoenix dactylifera L.) Using Ultrasonic-Assisted Extraction
by Fanar Alshammari, Md Badrul Alam, Marufa Naznin, Sunghwan Kim and Sang-Han Lee
Antioxidants 2024, 13(2), 238; https://doi.org/10.3390/antiox13020238 - 15 Feb 2024
Cited by 1 | Viewed by 1332
This study sought to optimize the ultrasonic-assisted extraction of polyphenolic compounds from unmature Ajwa date seeds (UMS), conduct untargeted metabolite identification and assess antioxidant and depigmenting activities. Response surface methodology (RSM) utilizing the Box–Behnken design (BBD) and artificial neural network (ANN) modeling was [...] Read more.
This study sought to optimize the ultrasonic-assisted extraction of polyphenolic compounds from unmature Ajwa date seeds (UMS), conduct untargeted metabolite identification and assess antioxidant and depigmenting activities. Response surface methodology (RSM) utilizing the Box–Behnken design (BBD) and artificial neural network (ANN) modeling was applied to optimize extraction conditions, including the ethanol concentration, extraction temperature and time. The determined optimal conditions comprised the ethanol concentration (62.00%), extraction time (29.00 min), and extraction temperature (50 °C). Under these conditions, UMS exhibited total phenolic content (TPC) and total flavonoid content (TFC) values of 77.52 ± 1.55 mgGAE/g and 58.85 ± 1.12 mgCE/g, respectively, with low relative standard deviation (RSD%) and relative standard error (RSE%). High-resolution mass spectrometry analysis unveiled the presence of 104 secondary metabolites in UMS, encompassing phenols, flavonoids, sesquiterpenoids, lignans and fatty acids. Furthermore, UMS demonstrated robust antioxidant activities in various cell-free antioxidant assays, implicating engagement in both hydrogen atom transfer and single electron transfer mechanisms. Additionally, UMS effectively mitigated tert-butyl hydroperoxide (t-BHP)-induced cellular reactive oxygen species (ROS) generation in a concentration-dependent manner. Crucially, UMS showcased the ability to activate mitogen-activated protein kinases (MAPKs) and suppress key proteins including tyrosinase (Tyr), tyrosinase-related protein-1 and -2 (Trp-1 and -2) and microphthalmia-associated transcription factor (MITF), which associated melanin production in MNT-1 cell. In summary, this study not only optimized the extraction process for polyphenolic compounds from UMS but also elucidated its diverse secondary metabolite profile. The observed antioxidant and depigmenting activities underscore the promising applications of UMS in skincare formulations and pharmaceutical developments. Full article
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