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Losada-Barreiro S, Paiva-Martins F, Bravo-Díaz C. Partitioning of Antioxidants in Edible Oil–Water Binary Systems and in Oil-in-Water Emulsions. Antioxidants (Basel) 2023; 12:antiox12040828. [PMID: 37107202 PMCID: PMC10135117 DOI: 10.3390/antiox12040828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/16/2023] [Accepted: 03/22/2023] [Indexed: 03/30/2023] Open
Abstract
In recent years, partitioning of antioxidants in oil–water two-phase systems has received great interest because of their potential in the downstream processing of biomolecules, their benefits in health, and because partition constant values between water and model organic solvents are closely related to important biological and pharmaceutical properties such as bioavailability, passive transport, membrane permeability, and metabolism. Partitioning is also of general interest in the oil industry. Edible oils such as olive oil contain a variety of bioactive components that, depending on their partition constants, end up in an aqueous phase when extracted from olive fruits. Frequently, waste waters are subsequently discarded, but their recovery would allow for obtaining extracts with antioxidant and/or biological activities, adding commercial value to the wastes and, at the same time, would allow for minimizing environmental risks. Thus, given the importance of partitioning antioxidants, in this manuscript, we review the background theory necessary to derive the relevant equations necessary to describe, quantitatively, the partitioning of antioxidants (and, in general, other drugs) and the common methods for determining their partition constants in both binary (PWOIL) and multiphasic systems composed with edible oils. We also include some discussion on the usefulness (or not) of extrapolating the widely employed octanol–water partition constant (PWOCT) values to predict PWOIL values as well as on the effects of acidity and temperature on their distributions. Finally, there is a brief section discussing the importance of partitioning in lipidic oil-in-water emulsions, where two partition constants, that between the oil-interfacial, POI, and that between aqueous-interfacial, PwI, regions, which are needed to describe the partitioning of antioxidants, and whose values cannot be predicted from the PWOIL or the PWOCT ones.
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Affiliation(s)
- Sonia Losada-Barreiro
- Departamento Química-Física, Facultad de Química, Universidade de Vigo, 36310 Vigo, Spain
- REQUIMTE-LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal
| | - Fátima Paiva-Martins
- REQUIMTE-LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal
| | - Carlos Bravo-Díaz
- Departamento Química-Física, Facultad de Química, Universidade de Vigo, 36310 Vigo, Spain
- Correspondence:
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Martínez-Senra T, Losada-Barreiro S, Hermida-Ramón JM, Graña AM, Bravo-Díaz C. Molecular Design of Interfaces of Model Food Nanoemulsions: A Combined Experimental and Theoretical Approach. Antioxidants (Basel) 2023; 12:antiox12020484. [PMID: 36830043 PMCID: PMC9951901 DOI: 10.3390/antiox12020484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/09/2023] [Accepted: 02/12/2023] [Indexed: 02/17/2023] Open
Abstract
The composition and structure of the interfacial region of emulsions frequently determine its functionality and practical applications. In this work, we have integrated theory and experiments to enable a detailed description of the location and orientation of antioxidants in the interfacial region of olive-oil-in-water nanoemulsions (O/W) loaded with the model gallic acid (GA) antioxidant. For the purpose, we determined the distribution of GA in the intact emulsions by employing the well-developed pseudophase kinetic model, as well as their oxidative stability. We also determined, by employing an in silico design, the radial distribution functions of GA to gain insights on its insertion depth and on its orientation in the interfacial region. Both theoretical and experimental methods provide comparable and complementary results, indicating that most GA is located in the interfacial region (~81.2%) with a small fraction in the aqueous (~18.82%). Thus, GA is an effective antioxidant to inhibit lipid oxidation in emulsions not only because of the energy required for its reaction with peroxyl radical is much lower than that between the peroxyl radical and the unsaturated lipid but also because its effective concentration in the interfacial region is much higher than the stoichiometric concentration. The results demonstrate that the hybrid approach of experiments and simulations constitutes a complementary and useful pathway to design new, tailored, functionalized emulsions to minimize lipid oxidation.
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Biochemistry of Antioxidants: Mechanisms and Pharmaceutical Applications. Biomedicines 2022; 10:biomedicines10123051. [PMID: 36551806 PMCID: PMC9776363 DOI: 10.3390/biomedicines10123051] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 11/29/2022] Open
Abstract
Natural antioxidants from fruits and vegetables, meats, eggs and fish protect cells from the damage caused by free radicals. They are widely used to reduce food loss and waste, minimizing lipid oxidation, as well as for their effects on health through pharmaceutical preparations. In fact, the use of natural antioxidants is among the main efforts made to relieve the pressure on natural resources and to move towards more sustainable food and pharmaceutical systems. Alternative food waste management approaches include the valorization of by-products as a source of phenolic compounds for functional food formulations. In this review, we will deal with the chemistry of antioxidants, including their molecular structures and reaction mechanisms. The biochemical aspects will also be reviewed, including the effects of acidity and temperature on their partitioning in binary and multiphasic systems. The poor bioavailability of antioxidants remains a huge constraint for clinical applications, and we will briefly describe some delivery systems that provide for enhanced pharmacological action of antioxidants via drug targeting and increased bioavailability. The pharmacological activity of antioxidants can be improved by designing nanotechnology-based formulations, and recent nanoformulations include nanoparticles, polymeric micelles, liposomes/proliposomes, phytosomes and solid lipid nanoparticles, all showing promising outcomes in improving the efficiency and bioavailability of antioxidants. Finally, an overview of the pharmacological effects, therapeutic properties and future choice of antioxidants will be incorporated.
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Bravo-Díaz C. Advances in the control of lipid peroxidation in oil-in-water emulsions: kinetic approaches †. Crit Rev Food Sci Nutr 2022; 63:6252-6284. [PMID: 35104177 DOI: 10.1080/10408398.2022.2029827] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Large efforts have been, and still are, devoted to minimize the harmful effects of lipid peroxidation. Much of the early work focused in understanding both the lipid oxidation mechanisms and the action of antioxidants in bulk solution. However, food-grade oils are mostly present in the form of oil-in-water emulsions, bringing up an increasing complexity because of the three-dimensional interfacial region. This review presents an overview of the kinetic approaches employed in controlling the oxidative stability of edible oil-in-water emulsions and of the main outcomes, with particular emphasis on the role of antioxidants and on the kinetics of the inhibition reaction. Application of physical-organic chemistry methods, such as the pseudophase models to investigate antioxidant partitioning, constitute a remarkable example on how kinetic methodologies contribute to model chemical reactivity in multiphasic systems and to rationalize the role of interfaces, opening new opportunities for designing novel antioxidants with tailored properties and new prospects for modulating environmental conditions in attempting to optimize their efficiency. Here we will summarize the main kinetic features of the inhibition reaction and will discuss on the main factors affecting its rate, including the determination of antioxidant efficiencies from kinetic profiles, structure-reactivity relationships, partitioning of antioxidants and concentration effects.
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Affiliation(s)
- Carlos Bravo-Díaz
- Facultad de Ciencias, Departamento de Química Física, Universidad de Vigo, Vigo, Spain
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Farooq S, Abdullah, Zhang H, Weiss J. A comprehensive review on polarity, partitioning, and interactions of phenolic antioxidants at oil-water interface of food emulsions. Compr Rev Food Sci Food Saf 2021; 20:4250-4277. [PMID: 34190411 DOI: 10.1111/1541-4337.12792] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 05/07/2021] [Accepted: 05/23/2021] [Indexed: 11/27/2022]
Abstract
There has been a growing interest in developing effective strategies to inhibit lipid oxidation in emulsified food products by utilization of natural phenolic antioxidants owing to their growing popularity over the past decades. However, due to the complexity of emulsified systems, the inhibition mechanism of phenolic antioxidants against lipid oxidation is rather complicated and not yet fully understood. In order to highlight the importance of polarity of phenolic antioxidants in emulsified systems according to the polar paradox, this review covers the recent progress on chemical, enzymatic, and chemoenzymatic lipophilization techniques used to modify the polarity of antioxidants. The partitioning behavior of phenolic antioxidants at the oil-water interface, which can be influenced by the presence of synthetic surfactants and/or antioxidant emulsifiers (e.g., polysaccharides, proteins, and phospholipids), is discussed. In addition, the emerging phenolic antioxidants among phenolic acids, flavonoids, tocopherols, and stilbenes applied in food emulsions are elaborated. As well, the interactions of polar-nonpolar antioxidants are stressed as a promising strategy to induce synergistic interactions at oil-water interface for improved oxidative stability of emulsions.
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Affiliation(s)
- Shahzad Farooq
- College of Biosystems Engineering and Food Science, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou, China
| | - Abdullah
- College of Biosystems Engineering and Food Science, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou, China
| | - Hui Zhang
- College of Biosystems Engineering and Food Science, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou, China.,Ningbo Research Institute, Zhejiang University, Ningbo, China
| | - Jochen Weiss
- Department of Food Physics and Meat Science, Institute of Food Science and Biotechnology, University of Hohenheim, Stuttgart, Germany
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Costa M, Losada-Barreiro S, Paiva-Martins F, Bravo-Díaz C. Polyphenolic Antioxidants in Lipid Emulsions: Partitioning Effects and Interfacial Phenomena. Foods 2021; 10:539. [PMID: 33807705 PMCID: PMC8001919 DOI: 10.3390/foods10030539] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/26/2021] [Accepted: 02/24/2021] [Indexed: 02/07/2023] Open
Abstract
The autoxidation of lipids in complex systems such as emulsions or biological membranes, although known to occur readily and to be associated with important pathological events, is lacking in quantitative data in spite of the huge efforts that have been made in attempting to unravel the complex mechanisms of lipid oxidation and its inhibition by antioxidants. Lipids are present as oil-in-water emulsions in many foods and pharmaceutical formulations, and the prevalent role of the interfacial region is critical to understand the antioxidant behavior and to correctly interpret antioxidant efficiencies. The aim of this review is to summarize the current knowledge on the chemical fate of antioxidants before they react with peroxyl radicals. Many researchers highlighted the predominant role of interfaces, and although some attempts have been made to understand their role, in most instances, they were essentially qualitative and based on putative hypotheses. It is only recently that quantitative reports have been published. Indeed, knowledge on the effects of relevant experimental variables on the effective concentrations of antioxidants is necessary for a successful design of alternate, effective antioxidative solutions.
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Affiliation(s)
- Marlene Costa
- REQUIMTE-LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal; (M.C.); (S.L.-B.); (F.P.-M.)
| | - Sonia Losada-Barreiro
- REQUIMTE-LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal; (M.C.); (S.L.-B.); (F.P.-M.)
- Department of Physical Chemistry, Faculty of Chemistry, Universidad de Vigo, 36200 Vigo, Spain
| | - Fátima Paiva-Martins
- REQUIMTE-LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal; (M.C.); (S.L.-B.); (F.P.-M.)
| | - Carlos Bravo-Díaz
- Department of Physical Chemistry, Faculty of Chemistry, Universidad de Vigo, 36200 Vigo, Spain
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García-Pérez P, Losada-Barreiro S, Bravo-Díaz C, Gallego PP. Exploring the Use of Bryophyllum as Natural Source of Bioactive Compounds with Antioxidant Activity to Prevent Lipid Oxidation of Fish Oil-In-Water Emulsions. PLANTS (BASEL, SWITZERLAND) 2020; 9:E1012. [PMID: 32796522 PMCID: PMC7464648 DOI: 10.3390/plants9081012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/06/2020] [Accepted: 08/06/2020] [Indexed: 12/13/2022]
Abstract
The current industrial requirements for food naturalness are forcing the development of new strategies to achieve the production of healthier foods by replacing the use of synthetic additives with bioactive compounds from natural sources. Here, we investigate the use of plant tissue culture as a biotechnological solution to produce plant-derived bioactive compounds with antioxidant activity and their application to protect fish oil-in-water emulsions against lipid peroxidation. The total phenolic content of Bryophyllum plant extracts ranges from 3.4 to 5.9 mM, expressed as gallic acid equivalents (GAE). The addition of Bryophyllum extracts to 4:6 fish oil-in-water emulsions results in a sharp (eight-fold) increase in the antioxidant efficiency due to the incorporation of polyphenols to the interfacial region. In the emulsions, the antioxidant efficiency of extracts increased linearly with concentration and levelled off at 500 μM GAE, reaching a plateau region. The antioxidant efficiency increases modestly (12%) upon increasing the pH from 3.0 to 5.0, while an increase in temperature from 10 to 30 °C causes a six-fold decrease in the antioxidant efficiency. Overall, results show that Bryophyllum plant-derived extracts are promising sources of bioactive compounds with antioxidant activity that can be eventually be used to control lipid oxidation in food emulsions containing (poly)unsaturated fatty acids.
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Affiliation(s)
- Pascual García-Pérez
- Applied Plant & Soil Biology, Plant Biology and Soil Science Department, Biology Faculty, University of Vigo, 36310 Vigo, Spain;
- CITACA, Agri-Food Research and Transfer Cluster, University of Vigo, 32004 Ourense, Spain
| | - Sonia Losada-Barreiro
- Physical Chemistry Department, Chemistry Faculty, University of Vigo, 36310 Vigo, Spain;
- REQUIMTE-LAQV, Chemistry and Biochemistry Department, Science Faculty, University of Porto, 4169-007 Porto, Portugal
| | - Carlos Bravo-Díaz
- Physical Chemistry Department, Chemistry Faculty, University of Vigo, 36310 Vigo, Spain;
| | - Pedro P. Gallego
- Applied Plant & Soil Biology, Plant Biology and Soil Science Department, Biology Faculty, University of Vigo, 36310 Vigo, Spain;
- CITACA, Agri-Food Research and Transfer Cluster, University of Vigo, 32004 Ourense, Spain
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Freiría-Gándara J, Losada-Barreiro S, Paiva-Martins F, Bravo-Díaz C. Enhancement of the antioxidant efficiency of gallic acid derivatives in intact fish oil-in-water emulsions through optimization of their interfacial concentrations. Food Funct 2018; 9:4429-4442. [PMID: 30070303 DOI: 10.1039/c8fo00977e] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The antioxidant (AO) efficiencies and the distributions of gallic acid (GA) and a series of alkyl gallates (propyl, PG, butyl, BG, octyl, OG and lauryl, LG) were determined in intact fish oil-in-water emulsions. The efficiency of the AOs in inhibiting the oxidation of the fish oil lipids increases upon increasing AO hydrophobicity up to a maximum (∼3-fold) at the octyl derivative, after which the efficiency decreases (LG). The observed non-linear variation in the efficiency with the AO alkyl chain length parallels those of the percentages of AOs in the interfacial region and of their interfacial concentrations, but does not parallel that of the percentage of AOs in the oil region. The interfacial AO concentrations are 20-100 times greater than the stoichiometric (added) antioxidant concentration, depending on the interfacial surfactant volume fraction ΦI, meanwhile the AO concentrations in the oil are similar or slightly higher (1-6 fold) and the concentrations in the aqueous region are much smaller (0.8-10 fold). The effects of the oil to water (o : w) ratio on the interfacial concentrations are complex and depend on both the hydrophobicity of the AO and ΦI. An increase in the o : w ratio favors incorporation of hydrophilic AOs to the interfacial region of emulsions but it decreases the incorporation of hydrophobic AOs. Results provide, for the first time, experimental evidence supporting the interfacial region of emulsions as the main site of production of lipid radicals. Results also provide physical evidence that the efficiency of AOs depends on their interfacial concentrations, which can be modulated by increasing the hydrophobicity of the AOs and by employing the minimum amount of surfactant necessary to stabilize the emulsions. Changes in the o : w ratio can also be used to modulate the interfacial concentrations of hydrophobic (OG, LG, and to a lesser extent BG) or hydrophilic (GA) AOs, but not those of AOs of intermediate hydrophobicity (PG).
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Affiliation(s)
- J Freiría-Gándara
- Universidad de Vigo, Fac. Química, Dpto. Químic- Física, 36310 Vigo, Spain.
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Aliaga C, López de Arbina A, Pastenes C, Rezende MC. Antioxidant-spotting in micelles and emulsions. Food Chem 2018; 245:240-245. [DOI: 10.1016/j.foodchem.2017.10.094] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 10/05/2017] [Accepted: 10/18/2017] [Indexed: 10/18/2022]
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Bravo‐Díaz C, Romsted LS, Losada‐Barreiro S, Paiva‐Martins F. Using a pseudophase model to determine AO distributions in emulsions: Why dynamic equilibrium matters. EUR J LIPID SCI TECH 2017. [DOI: 10.1002/ejlt.201600277] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Carlos Bravo‐Díaz
- Facultad de Química, Dpto. Química‐FísicaUniversidad de VigoVigoSpain
| | - Laurence S. Romsted
- Department of Chemistry and Chemical BiologyRutgers, the State University of New JerseyNew JerseyNew Jersey
| | - Sonia Losada‐Barreiro
- Facultad de Química, Dpto. Química‐FísicaUniversidad de VigoVigoSpain
- REQUIMTE‐LAQV, Departamento de Química e Bioquímica, Faculdade de CiênciasUniversidade do PortoPortoPortugal
| | - Fátima Paiva‐Martins
- REQUIMTE‐LAQV, Departamento de Química e Bioquímica, Faculdade de CiênciasUniversidade do PortoPortoPortugal
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Lopez de Arbina A, Rezende MC, Aliaga C. Cut-off effect of radical TEMPO derivatives in olive oil-in-water emulsions. Food Chem 2017; 224:342-346. [DOI: 10.1016/j.foodchem.2016.12.058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 11/16/2016] [Accepted: 12/20/2016] [Indexed: 01/29/2023]
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Silva R, Losada-Barreiro S, Paiva-Martins F, Bravo-Díaz C. Partitioning and antioxidative effect of protocatechuates in soybean oil emulsions: Relevance of emulsifier concentration. EUR J LIPID SCI TECH 2017. [DOI: 10.1002/ejlt.201600274] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Rui Silva
- REQUIMTE-LAQV; Departamento de Química e Bioquímica; Faculdade de Ciências; Universidade do Porto; Porto Portugal
| | - Sonia Losada-Barreiro
- REQUIMTE-LAQV; Departamento de Química e Bioquímica; Faculdade de Ciências; Universidade do Porto; Porto Portugal
- Faculty of Chemistry; Department of Physical Chemistry; University of Vigo; Vigo Spain
| | - Fátima Paiva-Martins
- REQUIMTE-LAQV; Departamento de Química e Bioquímica; Faculdade de Ciências; Universidade do Porto; Porto Portugal
| | - Carlos Bravo-Díaz
- Faculty of Chemistry; Department of Physical Chemistry; University of Vigo; Vigo Spain
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Costa M, Losada-Barreiro S, Paiva-Martins F, Bravo-Díaz C. Physical evidence that the variations in the efficiency of homologous series of antioxidants in emulsions are a result of differences in their distribution. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2017; 97:564-571. [PMID: 27097916 DOI: 10.1002/jsfa.7765] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 04/17/2016] [Accepted: 04/18/2016] [Indexed: 06/05/2023]
Abstract
BACKGROUND The relationships between the hydrophilic-lipophilic balance (HLB) of antioxidants (AOs) and their distributions and efficiencies in emulsions are not fully understood. Recent reports indicate that, for series of homologous antioxidants of different hydrophobicity, the variation of their efficiency with the HLB of the AO increases with the alkyl chain length up to a maximum (C3 -C8 ester) followed by a decrease (cut-off effect). RESULTS We determined the distributions of a series of caffeic acid derivatives in intact soybean emulsions by employing a specifically designed chemical probe located in the interfacial region of the emulsion. We also determined the AO efficiencies in the very same emulsions. We demonstrate that the variation of the percentage of AO in the interfacial region of soybean oil-in-water emulsions with the AO HLB parallels that of their antioxidant efficiency. CONCLUSION The results provide physical evidence that the variations in the efficiency of homologous series of antioxidants in emulsions are the result of differences in their distribution. The results confirm that, with other things being equal, there is a direct relationship between the percentage of AO in the interfacial region of the emulsions and their efficiency, providing a natural explanation, based on molecular properties, of the cut-off effect. © 2016 Society of Chemical Industry.
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Affiliation(s)
- Marlene Costa
- REQUIMTE-LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, 4169-007, Portugal
| | - Sonia Losada-Barreiro
- REQUIMTE-LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, 4169-007, Portugal
- Department of Physical Chemistry, Faculty of Chemistry, University of Vigo, Vigo, 36200, Spain
| | - Fátima Paiva-Martins
- REQUIMTE-LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, 4169-007, Portugal
| | - Carlos Bravo-Díaz
- Department of Physical Chemistry, Faculty of Chemistry, University of Vigo, Vigo, 36200, Spain
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Dudzik A, Jaszczuk K, Losada-Barreiro S, Bravo-Díaz C. Kinetic evidence for the formation of diazo ethers in the course of reactions between arenediazonium ions and antioxidants. NEW J CHEM 2017. [DOI: 10.1039/c6nj03670h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Non-zero, pH-dependent, saturation kinetics are observed in the course of the reaction between 3-methylbenzenediazonium ions and hydroxytyrosol.
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Affiliation(s)
- Anna Dudzik
- Faculty of Chemistry
- Maria Curie-Skłodowska University
- Lublin
- Poland
- Dpt. Química Física
| | - Katarzyna Jaszczuk
- Faculty of Chemistry
- Maria Curie-Skłodowska University
- Lublin
- Poland
- Dpt. Química Física
| | | | - Carlos Bravo-Díaz
- Dpt. Química Física
- Facultad de Química
- Universidad de Vigo
- Vigo-Pontevedra
- Spain
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Partitioning of vanillic acid in oil-in-water emulsions: Impact of the Tween®40 emulsifier. Food Res Int 2016; 88:61-69. [DOI: 10.1016/j.foodres.2016.06.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 06/07/2016] [Accepted: 06/15/2016] [Indexed: 01/21/2023]
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Aliaga C, López de Arbina A, Rezende MC. “Cut-off” effect of antioxidants and/or probes of variable lipophilicity in microheterogeneous media. Food Chem 2016; 206:119-23. [DOI: 10.1016/j.foodchem.2016.03.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 02/09/2016] [Accepted: 03/08/2016] [Indexed: 10/22/2022]
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