Why Encapsulate Antioxidants in Emulsion-Based Systems, Where They Are Located, and How Location Affects Their Efficiency

Losada‐Barreiro, Sonia; Bravo‐Díaz, Carlos; Paiva‐Martins, Fátima

doi:10.1007/978-3-030-62052-3_1

Cited by 6 publications

(16 citation statements)

References 97 publications

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“…Our research on antioxidants in fluid emulsions over the past decade demonstrates that the dynamic equilibrium condition holds provided that the emulsions are either kinetically stable or gently stirred after initial mixing because the intermolecular interactions between molecules and ions in emulsions are generally weak and their diffusivities should be orders of magnitude faster than the rates of thermal reaction [ 3 , 4 , 19 , 24 , 25 , 34 , 57 , 58 , 59 , 60 , 61 , 62 , 63 ].…”

Section: Dynamic Aspects Of Emulsions and Mass Transfermentioning

confidence: 99%

“…The three-dimensional interfaces between two immiscible liquids (oil and water) found in emulsions and other colloidal systems have been widely used as models of membrane function to mimic their behavior, as models of lipid-based foods and to model important (bio)chemical reactions such as the oxidation of lipids [ 1 , 2 , 3 , 4 ]. A variety of fundamental processes involved in biocatalysis, such as ion pumping, electron transport, membrane fusion, and photosynthesis, have all been investigated in such interfacial systems for further guidance in developing new biomaterials and medicines and to better understand life science [ 5 , 6 , 7 , 8 , 9 , 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

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Modeling Chemical Reactivity at the Interfaces of Emulsions: Effects of Partitioning and Temperature

2021

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Bulk phase chemistry is hardly ever a reasonable approximation to interpret chemical reactivity in compartmentalized systems, because multiphasic systems may alter the course of chemical reactions by modifying the local concentrations and orientations of reactants and by modifying their physical properties (acid-base equilibria, redox potentials, etc.), making them—or inducing them—to react in a selective manner. Exploiting multiphasic systems as beneficial reaction media requires an understanding of their effects on chemical reactivity. Chemical reactions in multiphasic systems follow the same laws as in bulk solution, and the measured or observed rate constant of bimolecular reactions can be expressed, under dynamic equilibrium conditions, in terms of the product of the rate constant and of the concentrations of reactants. In emulsions, reactants distribute between the oil, water, and interfacial regions according to their polarity. However, determining the distributions of reactive components in intact emulsions is arduous because it is physically impossible to separate the interfacial region from the oil and aqueous ones without disrupting the existing equilibria and, therefore, need to be determined in the intact emulsions. The challenge is, thus, to develop models to correctly interpret chemical reactivity. Here, we will review the application of the pseudophase kinetic model to emulsions, which allows us to model chemical reactivity under a variety of experimental conditions and, by carrying out an appropriate kinetic analysis, will provide important kineticparameters.

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Section: Dynamic Aspects Of Emulsions and Mass Transfermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling Chemical Reactivity at the Interfaces of Emulsions: Effects of Partitioning and Temperature

2021

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“…The oxidation reaction may be hindered by the addition of antioxidants (ArO-H) that regenerate the parent lipid by donation of an H-atom to the peroxyl radical. Further details on the mechanism of the reactions can be found elsewhere [ 12 , 13 , 46 ]. In: any initiator, LH: unsaturated fatty acid, ArOH: antioxidant, LOO • : peroxyl radical, ArO • : radical derived from the antioxidant.…”

Section: Figures Schemes and Tablesmentioning

confidence: 99%

“…Control of the lipid oxidation reaction is, therefore, a challenge not only for the food industry but also for the pharmaceutical industry, where unsaturated lipids are employed in the formulation of products of interest, such as the nutritive emulsions employed in parenteral nutrition, and for the cosmetics industry, where they are widely used in the preparation of lotions, beauty creams, etc. One of the most effective ways of inhibiting the oxidation of lipid-based foods is the incorporation of antioxidants, AOs, which are molecules capable of donating H-atoms to lipid radicals to regenerate them [ 4 , 12 , 13 ]. The efficiency of the AOs in inhibiting lipid oxidation is usually assessed in terms of the rate of the chemical reaction between the AO and the lipid radical, which depends on, among others, the effective concentrations of the antioxidant in the interfacial region of the emulsions [ 13 , 14 , 15 , 16 , 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

Effects of Surfactant Volume Fraction on the Antioxidant Efficiency and on The Interfacial Concentrations of Octyl and Tetradecyl p-Coumarates in Corn Oil-in-Water Emulsions

2021

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Surfactants have been used for decades in the food industry for the preparation of lipid-based emulsified food stuffs. They play two main roles in the emulsification processes: first they decrease the interfacial tension between the oil and water, facilitating droplet deformation and rupture; second, they reduce droplet coalescence by forming steric barriers. However, addition of surfactants to binary oil-water mixtures also brings up the formation of three-dimensional interfacial layers, surrounding each emulsion droplet, that significantly alter chemical reactivity. This is the case, for instance, in the inhibition reaction between antioxidants and the lipid radicals formed in the course of the spontaneous oxidation reaction of unsaturated lipids, which are commonly employed in the preparation of food-grade emulsions. The rate of the inhibition reaction depends on the effective concentrations of antioxidants, which are mostly controlled by the amount of surfactant employed in the preparation of the emulsion. In this work, we analyze the effects of the surfactant Tween 20 on the oxidative stability and on the effective concentrations of two model antioxidants derived from cinnamic acid, determining their interfacial concentrations in the intact emulsions to avoid disrupting the existing equilibria and biasing results. For this purpose, a recently developed methodology was employed, and experimental results were interpreted on the grounds of a pseudophase kinetic model.

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“…Currently, the distribution of antioxidants is recognized as a crucial issue regarding their efficiency at inhibiting the oxidation of target biomolecules in multiphasic systems. Current research links the quantitative distribution of antioxidants in complex multiphasic systems with the selection or design of antioxidants that preferentially distribute at the bio-interfaces [ 18 , 47 , 50 ].…”

Section: Introductionmentioning

confidence: 99%

Polyphenols as Antioxidants for Extending Food Shelf-Life and in the Prevention of Health Diseases: Encapsulation and Interfacial Phenomena

et al. 2021

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Toxicity caused by the exposure to human-made chemicals and environmental conditions has become a major health concern because they may significantly increase the formation of reactive oxygen species (ROS), negatively affecting the endogenous antioxidant defense. Living systems have evolved complex antioxidant mechanisms to protect cells from oxidative conditions. Although oxidative stress contributes to various pathologies, the intake of molecules such as polyphenols, obtained from natural sources, may limit their effects because of their antioxidant and antimicrobial properties against lipid peroxidation and against a broad range of foodborne pathogens. Ingestion of polyphenol-rich foods, such as fruits and vegetables, help to reduce the harmful effects of ROS, but the use of supramolecular and nanomaterials as delivery systems has emerged as an efficient method to improve their pharmacological and therapeutic effects. Suitable exogenous polyphenolic antioxidants should be readily absorbed and delivered to sites where pathological oxidative damage may take place, for instance, intracellular locations. Many potential antioxidants have a poor bioavailability, but they can be encapsulated to improve their ideal solubility and permeability profile. Development of effective antioxidant strategies requires the creation of new nanoscale drug delivery systems to significantly reduce oxidative stress. In this review we provide an overview of the oxidative stress process, highlight some properties of ROS, and discuss the role of natural polyphenols as bioactives in controlling the overproduction of ROS and bacterial and fungal growth, paying special attention to their encapsulation in suitable delivery systems and to their location in colloidal systems where interfaces play a crucial role.

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Why Encapsulate Antioxidants in Emulsion-Based Systems, Where They Are Located, and How Location Affects Their Efficiency

Cited by 6 publications

References 97 publications

Modeling Chemical Reactivity at the Interfaces of Emulsions: Effects of Partitioning and Temperature

Modeling Chemical Reactivity at the Interfaces of Emulsions: Effects of Partitioning and Temperature

Effects of Surfactant Volume Fraction on the Antioxidant Efficiency and on The Interfacial Concentrations of Octyl and Tetradecyl p-Coumarates in Corn Oil-in-Water Emulsions

Polyphenols as Antioxidants for Extending Food Shelf-Life and in the Prevention of Health Diseases: Encapsulation and Interfacial Phenomena

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