Oxidation and oxidative stability in emulsions

A review on polysaccharide-based tumor targeted drug nanodelivery systems

The tumor-targeted drug delivery system (TTDNS) uses nanocarriers to transport chemotherapeutic agents to target tumor cells or tissues precisely. This innovative approach considerably increases the effective concentration of these drugs at the tumor site, thereby enhancing their therapeutic efficacy. Many chemotherapeutic agents face challenges, such as low bioavailability, high cytotoxicity, and inadequate drug resistance. To address these obstacles, TTDNS comprising natural polysaccharides have gained increasing popularity in the field of nanotechnology owing to their ability to improve safety, bioavailability, and biocompatibility while reducing toxicity. In addition, it enhances permeability and allows for controlled drug delivery and release. This review focuses on the sources of natural polysaccharides and their direct and indirect mechanisms of anti-tumor activity. We also explored the preparation of various polysaccharide-based nanocarriers, including nanoparticles, nanoemulsions, nanohydrogels, nanoliposomes, nanocapsules, nanomicelles, nanocrystals, and nanofibers. Furthermore, this review delves into the versatile applications of polysaccharide-based nanocarriers, elucidating their capabilities for in vivo targeting, controlled release, and responsiveness to endogenous and exogenous stimuli, such as pH, reactive oxygen species, glutathione, light, ultrasound, and magnetic fields. This sophisticated design substantially enhances the chemotherapeutic efficacy of the encapsulated drugs at tumor sites and provides a basis for preclinical and clinical research. However, the in vivo stability, drug loading, and permeability of these preparations into tumor tissues still need to be improved. Most of the currently developed biomarker-sensitive polysaccharide nanocarriers are still in the laboratory stage, more innovative delivery mechanisms and clinical studies are needed to develop commercial nanocarriers for medical use.

Use of emulsifying plant protein hydrolysates from winery, whiskey and brewery by-products for the development of echium oil delivery emulsions

This study investigates the production of plant protein hydrolysates from defatted grape seed flour and barley spent grains, by-products of wine, beer and whiskey industries, using limited hydrolysis with subtilisin or trypsin. The hydrolysates were characterized by protein content, molecular weight, antioxidant capacity, interfacial adsorption, dilatational rheology, and interfacial conformational changes using synchrotron radiation circular dichroism. Physical and oxidative stability of 5 % echium oil-in-water emulsions (pH 7), stabilized by the hydrolysates, were studied during seven days of storage. The trypsin-derived hydrolysate from brewers' spent grains resulted in the most physically stable emulsion due to enhanced interfacial adsorption and higher dilatational modulus. Alternatively, the trypsin-treated grape seed flour hydrolysate provided the emulsion with the highest oxidative stability, aligning with its superior in vitro antioxidant capacity. These results show the potential of wine and brewery industry side streams as a sustainable source of plant-based emulsifiers with application in omega-3 delivery systems.

Fabrication and characterization of antioxidant fish oil Pickering emulsions stabilized by selenium nanoparticles-loaded whey protein concentrate and phloretin complex

This study aimed to enhance the nutritional value and oxidative stability of fortified milk by investigating the properties of fish oil Pickering emulsion (FOPE) stabilized by selenium nanoparticles (SeNP) loaded-whey protein concentrate/phloretin (WPC/PHL) complex. Initially, the influence of SeNP concentration on the WPC/PHL complex was evaluated through measurements of particle size, antioxidant activity, and intermolecular interactions. Results demonstrated that increasing SeNP concentration from 0.1 % to 0.3 % significantly enhanced the antioxidant activity, with ABTS assay values rising from 42.87 % to 76.14 % and DPPH assay values increasing from 59.10 % to 86.11 %. FTIR and docking analyses confirmed the formation of bonds (hydrogen and van der Waals) between the WPC/PHL/SeNP nanoparticles. Subsequently, the FOPEs were characterized, revealing that increasing SeNP concentration reduced droplet size, indicating improved emulsion stability. Furthermore, the oxidative stability of the emulsions improved with increasing SeNP concentrations (0.1 % to 0.3 %), as evidenced by a decrease in peroxide value (PV) from 4.27 meq/kgO2 to 2.83 meq/kgO2 and a reduction in malondialdehyde (MDA) content from 86.61 mg/kg oil to 62.78 mg/kg oil after 10 days of storage. Finally, the oxidative stability of fortified milk containing these FOPEs was also significantly enhanced. These findings provide a novel perspective on developing SeNP as an antioxidant particle, potentially suitable for formulating functional emulsified food products susceptible to oxidative deterioration.

Oil-in-water Pickering emulsions with Buriti vegetable oil stabilized with cellulose nanofibrils: Preparation, stability and antimicrobial properties

Mauritia flexuosa (Buriti) vegetable oil (OV) has attracted technological interest in various sectors, including pharmaceuticals, food, and beverages, because of its excellent antioxidant activity. The active OV components are fatty compounds, and stability is required for proper application. In this work, we investigated OV-in-water Pickering emulsions stabilized by cellulose nanofibrils (CNF). CNF is sustainable, economically viable, and environmentally friendly, and it is suitable for developing products in an eco-friendly way. The factorial design of experiments (DoE) indicates that the amount of CNF and the homogenization time significantly affect the emulsion, preventing coalescence over 30 days. Fourier-transform Raman spectroscopy (FT-Raman) and Fourier-transform infrared spectroscopy (FTIR) show that CNF stabilizes the OV droplets through induced dipole-dipole interactions and hydrogen bonds. Rheological analysis was relevant to the relationship between internal microstructure strength and viscous flow behavior of the emulsions. A novel approach enabled the identification of the CNF stabilization mechanism in the emulsion system via fluorescence microscopy. Diameter distribution measurements and steady-state rheological tests indicate that the emulsions have good stability at room temperature and suitable steady-state viscosity for food applications and beverage products as they show pronounced shear thinning behavior for cream and lotion skin care products.

Fabrication of interfacial crystallized oleogel emulsion for quercetin delivery with enhanced environmental stability and bioaccessibility

BACKGROUND

Quercetin is a flavonoid compound with numerous bioactivities. However, the low solubility, easy degradation and low bioaccessibility limit its application. In this study, a novel interfacial crystallized oleogel emulsion was fabricated, where beeswax was used as the oleogelator, for quercetin encapsulation with enhanced stability and bioaccessibility.

RESULTS

The process of interfacial crystallization was investigated using interfacial rheology and polarized microscopy, with a positive correlation between crystal density and beeswax content in the oil phase. Emulsion stability was directly linked to beeswax concentration in the oil phase, with 100 mg g-1 showing enhanced stability under storage, UVB light exposure and ionic conditions. Beeswax addition significantly increased the quercetin loading capacity of the emulsion; particularly, at a 200 mg g-1 beeswax concentration, the loading capacity was improved by 285.55%, and the environmental stability was enhanced against UV light and Ca2+. Ultimately, in vitro simulated digestion experiment indicated improved bioaccessibility of quercetin.

CONCLUSIONS

This strategy significantly enriched the formulation of oleogel emulsion and its potential applications in delivering bioactive ingredients with high environmental vulnerability. © 2024 Society of Chemical Industry.

Maltodextrin vitamin E succinate: A novel antioxidant emulsifier for formulating functional nanoemulsions

A new multifunctional emulsifier was synthesized by coupling maltodextrin with a dextrose equivalent of 19 to vitamin E succinate. Two emulsifiers with varying degrees of vitamin E succinate substitution were prepared based on different mass ratios of vitamin E succinate to maltodextrin. The molecular structure and purity of these emulsifiers were analyzed. Nanoemulsions were prepared using octenyl succinic anhydride modified starch as a control to investigate the physical stability, antioxidant capacity, oxidative stability, and in vitro simulated digestive properties of the nanoemulsions. The emulsifying and antioxidant activity of the maltodextrin-vitamin E succinate conjugate was significantly superior to that of octenyl succinic anhydride modified starch, demonstrating good physical and oxidative stability. Additionally, they were rapidly digested under simulated small intestinal conditions. This new emulsifier shows broad application potential for the encapsulation, protection, and delivery of hydrophobic bioactive substances in the fields of medicine, food, and healthcare products.

Enhancing walnut butter with a pea protein isolate-pectin-pterostilbene complex: Physicochemical properties and stability analysis

To explore the potential applications of pea protein isolate-pectin-pterostilbene complex (PPI-PEC-PT) in the sauce industry, its solubility, antioxidant capacity and oxidative stability were measured. The results indicated that PPI-PEC-PT exhibited a solubility of 77.67 %, more than double that of PPI-PT (31.93 %). The DPPH radical scavenging capacity of PPI-PEC-PT reached up to 78.52 % at a concentration of 50 μg/mL. After accelerated oxidation (60 °C, 7 days), the peroxide value (8.15 mmol/L) and malondialdehyde content (11.50 mmol/L) of PPI-PEC-PT emulsion were significantly lower than those of PPI. Additionally, when applied to walnut butter, PPI-PEC-PT significantly enhanced its gel properties. In conclusion, PPI-PEC-PT could not only serve as a natural antioxidant but also be utilized as a food additive to enhance the gelling properties of products in the food industry.

Fabrication and characterization of oleic acid/sesame protein isolate/ poly (vinyl) alcohol core-shell nanofibers: Mitigating lipid oxidation by emulsion electrospinning

Formulated oil-in-water (O/W) emulsions of oleic acid (OA) using sesame protein isolate (SPI) were processed via emulsion electrospinning with poly (vinyl) alcohol (PVA) to fabricate core-shell nanofibers for lipid oxidation prevention. The emulsion droplet size and viscosity increased as the oil volume fraction rose from 5 % to 30 %. The morphology tests and Fourier transform infrared spectroscopy (FTIR) confirmed the uniformity of nanofibers and OA encapsulation with hydrogen bonding. The thermal stability, mechanical properties, and water contact angle (WCA) of the nanofiber films improved with increased OA content. Encapsulation efficiency was 94.76 % and storage stability was maintained for 7 days in 5 % oil fraction nanofibers. The nanofibers showed lower oxidation and superior oxidative resistance to free OA, with the lowest peroxide value (POV, 2.14 mmol/L) and thiobarbituric acid-reactive substances (TBARS, 36.75 μmol/L). In conclusion, the OA/SPI/PVA (PE) core-shell nanofibers via emulsion electrospinning are efficient for fatty acid encapsulation in functional foods.

Garlic and Chitosan Improve the Microbial Quality of Hummus and Reduce Lipid Oxidation

This study investigated the antimicrobial and antioxidant effects of garlic and chitosan on hummus. Hummus was prepared by using 0.5% or 1% (w/w) chitosan, with or without 1% (w/w) garlic, and samples were stored at 4, 10, or 25 °C for 28, 21, or 7 d, respectively. The behavior of lactic acid bacteria (LAB), Pseudomonas spp., aerobic bacteria, and yeasts and molds was then investigated. Color, pH, TBARS, and rheological properties were also measured. In hummus, both with and without garlic, chitosan added at 0.5% and 1% w/w significantly (p < 0.05) decreased LAB, aerobic bacteria, yeasts, and molds, and Pseudomonas spp., at 4 °C. However, at 10 °C, adding chitosan at 1% w/w significantly reduced only aerobic bacteria (2.2 log cfu/g) and Pseudomonas spp. (1.0 log cfu/g). The pH values (regardless of treatment) decreased upon storage. The addition of garlic or chitosan did not significantly affect the lightness (L*) or yellowness (b*). However, garlic, regardless of chitosan concentration, notably reduced lipid oxidation (0.8-1.4 MDA Eq/kg of sample) and had a greater impact on the sensory properties compared to chitosan. The results of this study will encourage producers to produce hummus that has a better flavor due to garlic with enhanced microbial quality.

Advancements in Biosensors for Lipid Peroxidation and Antioxidant Protection in Food: A Critical Review

This review highlights the progress made in recent years on biosensors aimed at detecting relevant analytes/markers of food peroxidation. Starting from the basic definition of biosensors and the chemical features of peroxidation, here we describe the different approaches that can be used to obtain information about the progress of peroxidation and the efficacy of antioxidants. Aptamers, metal-organic frameworks, nanomaterials, and supported enzymes, in conjunction with electrochemical methods, can provide fast and cost-effective detection of analytes related to peroxidation, like peroxides, aldehydes, and metals. The determination of (poly)phenols concentrations by biosensors, which can be easily obtained by using immobilized enzymes (like laccase), provides an indirect measure of peroxidation. The rationale for developing new biosensors, with a special focus on food applications, is also discussed.

Dynamic analysis of bovine bone high-temperature hydrolysate emulsion formation based on microstructure and physicochemical interactions

In the food industry, the emulsifying process alters both the stability and quality of the emulsified products prepared by bovine bone high-temperature hydrolysate (BBHH). The microstructure and interactions of BBHH emulsion were characterized by cryo-scanning electron microscopy (Cryo-SEM) and Raman spectroscopy during emulsification. Notably, BBHH emulsion exhibited the best properties under emulsifying for 120 s, attributed to its interfacial adsorption characteristics. In terms of microstructure, the droplets were small and uniform, and the cross-linking and network structure between the droplet surfaces were obvious at 120 s. Raman spectroscopy indicated that the adsorption of BBHH at the oil-water interface mainly involved an increase of the β-sheet at the expense of the α-helix region. In addition, protein adsorption and structural development at the interface were driven by hydrophobic interactions, while further rearrangement and polymerization were mediated by disulfide bonds. Furthermore, the stability and particle size distribution of the emulsion also supported the results. This study provided a theoretical basis for the behavior of BBHH emulsion formation, which expanded valuable insights into the mechanisms by which liquid food emulsification systems mediated by animal-derived proteins and how they behave under a variety of external conditions.

Super-resolution imaging lysosome vesicles and establishing a gallbladder-visualizable zebrafish model via a fluorescence probe

Advanced probes for imaging viscous lipids microenvironment in vitro and in vivo are desirable for the study of membranous organelles and lipids traffic. Herein, a reaction-based dihydroquinoline probe (DCQ) was prepared via linking a diethylamino coumarin fluorophore with a N-methylquinoline moiety. DCQ is stable in low viscous aqueous mediums and exhibits green fluorescence, which undergoes fast autoxidation in high viscous mediums to form a fluorescent product with deep-red to near-infrared (NIR) emission, rendering the ability for dual-color imaging. Living cell imaging indicated that DCQ can effectively stain lysosomal membranes with deep-red fluorescence. Super-resolution imaging of lysosome vesicles has been achieved by DCQ and stimulated emission depletion (STED) microscopy. In addition, DCQ realizes multiple organs imaging in zebrafish, whose dual-color emission can perfectly discriminate zebrafish's yolk sac, digestive tract and gallbladder. Most importantly, DCQ has been successfully used to establish a gallbladder-visualizable zebrafish model for the evaluation of drug stress.

Preparation and characterization of agarose-sodium alginate hydrogel beads for the co-encapsulation of lycopene and resveratrol nanoemulsion

In the study, lycopene and resveratrol nanoemulsion hydrogel beads were prepared by using agarose‑sodium alginate as a carrier and the semi-interpenetrating polymer network technique, characteristics and morphologies were evaluated by scanning electron microscopy, fluorescence microscopy, rheological measurement. The synergistic antioxidant effect of lycopene and resveratrol was confirmed, the best synergistic antioxidant performance is achieved when the ratio of 1:1. To increase the solubility and improve the stability, the lycopene was prepared as solid dispersion added to the nanoemulsion. The encapsulation rate of lycopene and resveratrol reached 93.60 ± 2.94 % and 89.30 ± 1.75 %, respectively, and the cumulative release showed that the addition of agarose slowed down the release rate of the compound, which improves the applicability of lycopene and resveratrol and development of carriers for the delivery of different bioactive ingredients.

Oxidative Stability of Fish Oil-Loaded Nanocapsules Produced by Electrospraying Using Kafirin or Zein Proteins as Wall Materials

The encapsulation of fish oil by monoaxial electrospraying using kafirin or zein proteins as hydrophobic wall materials was investigated. Kafirin resulted in spherical fish oil-loaded nanocapsules (>50% of capsules below 1 µm), whereas zein led to fish oil-loaded nanocapsules with non-spherical morphology (>80% of capsules below 1 µm). Both hydrophobic encapsulating materials interacted with fish oil, successfully entrapping the oil within the protein matrix as indicated by Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy results. FTIR also suggested hydrogen bonding between fish oil and the proteins. Trapped radicals in the encapsulation matrix that were detected by electron paramagnetic resonance (EPR), indicated oxidation during electrospraying and storage. Results from isothermal (140 °C) differential scanning calorimetry (DSC) denoted that the encapsulation of fish oil by electrospraying using both kafirin or zein as wall materials protected fish oil from oxidation. In particular, the zein-based nanocapsules were 3.3 times more oxidatively stable than the kafirin-based nanocapsules, which correlates with the higher oil encapsulation efficiency found for zein-based capsules. Thus, this study shows that kafirin might be considered a hydrophobic wall material for the encapsulation of fish oil by electrospraying, although it prevented lipid oxidation to a lower extent when compared to zein.

Lipophilized rosmarinic acid: Impact of alkyl type and food matrix on antioxidant activity, and optimized enzymatic production

In this study, the initial focus was on exploring the simultaneous impact of the oil-based food matrix and the polarity of rosmarinic acid derivatives on the antioxidant properties. Rosmarinic acid (RA) showed remarkable DPPH, FRAP, and ABTS radical scavenging activities, followed by methyl rosmarinate (MR) and ethyl rosmarinate (ER). In bulk oil, both conjugated dienes and p-AnV values reached a peak in the following order after 30 days: ER > MR > RA = BHT > control (no antioxidant). In the oil structured using monoacylglycerol, MR was more effective than ER and RA. For ethyl cellulose oleogel, emulsion, and gelled emulsion systems, RA was more effective. Additionally, after confirming the importance of the food matrix on the antioxidant activity of RA derivatives, the lipophilization of RA with ethanol was optimized as a model with Lipozyme 435 in hexane. A conversion yield of as high as 85.59% for ER was achieved, as quantified by HPLC-UV and confirmed by HPLC-DAD-ESI-qTOFMS.

Formation mechanism of off-flavor and the inhibition regulatory strategies in the algal oil-loaded emulsions-a review

Algal oil rich in docosahexaenoic acid is easily oxidized and degraded to produce volatile short-chain compounds, leading to the deterioration of product flavor. Currently, the emulsion delivery of algal oil provides a promising approach to minimize oxidative deterioration and conceal its off-flavor. However, algal oil emulsions would also experience unanticipated oxidation as a result of the large specific surface area between the aqueous phase and the oil phase. The current paper offers a mechanism overview behind off-flavor formation in algal oil emulsions and explores corresponding strategies for the inhibition regulation. Additionally, the paper delves into the factors influencing lipid oxidation and the perception of off-flavors in such emulsions. To mitigate the development of off-flavors in algal oil emulsions resulting from oxidation, it is crucial to decline the likelihood of lipid oxidation and proactively prevent the creation of off-flavors whenever possible. Minimizing the release of volatile off-flavor compounds that are inevitably generated is also considered effective for weakening off-flavor. Moreover, co-encapsulation with particular desirable aroma substances could improve the overall flavor characteristics of emulsions.

The role of fat content in coconut milk: Stability and digestive properties

The fat in coconut milk contributes to unique flavour, while increasing fat content affects stability of the coconut milk. In this study, coconut water and fat were separated, recombined, and homogenized to obtain coconut milk with different fat contents (0-20 %). Emulsifying properties, stability, and digestibility of coconut milk with different fat contents were comprehensively evaluated. The results showed that as the fat content increased from 0 to 20 %, the droplet size increased from 2.18 to 4.70 μm and the viscosity showed an increasing trend. During storage and freeze-thaw, coconut milk with 5 % and 10 % fat content showed excellent stability. In addition, coconut milk with 10 % fat content had superior fat digestibility, which was related to high affinity of pancrelipase. In short, this study revealed that fat content below 10 % can withstand environmental factors such as storage, lipid oxidation, and freeze-thaw, which can be accurately developed as coconut milk products.

A Comparative Study of Dairy and Non-Dairy Milk Types: Development and Characterization of Customized Plant-Based Milk Options

Plant-based milk has gained considerable attention; however, its high nutritional variation highlights the need for improved formulation designs to enhance its quality. This study aimed to nutritionally compare cow milk with plant-based milk produced from hazelnuts (H), Brazil nuts (BN), cashew nuts (CN), soybeans (S), and sunflower seeds (SS), and to perform physicochemical and technological characterization. The plant-based milk produced with isolated grains showed a nutritional composition inferior to that of cow milk in almost all evaluated parameters, protein content (up to 1.1 g 100 g-1), lipids (up to 2.7 g 100 g-1), color parameters, minerals, and especially calcium (up to 62.4 mg L-1), which were originally high in cow milk (up to 1030 mg L-1). However, the plant-based milk designed using a blend composition was able to promote nutritional enhancement in terms of minerals, especially iron (Fe) and magnesium (Mg), high-quality lipids (up to 3.6 g 100 g-1), and carbohydrates (3.4 g 100 g-1 using CN, BN, and S). The protein content was 1.3% compared to 5.7 in cow milk, and the caloric value of plant-based milk remained 32.8 at 52.1 kcal, similar to cow milk. Satisfactory aspects were observed regarding the shelf life, especially related to microbiological stability during the 11 d of storage at 4 °C. For the designed plant-based milk to be equivalent to cow milk, further exploration for optimizing the blends used to achieve better combinations is required. Furthermore, analyzing possible fortification and preservation methods to increase shelf life and meet the nutritional and sensory needs of the public would be interesting.

Constructing myosin/high-density lipoprotein composite emulsions: Roles of pH on emulsification stability, rheological and structural properties

The emulsification activity of myosin plays a significant role in affecting quality of emulsified meat products. High-density lipoprotein (HDL) possesses strong emulsification activity and stability due to its structural characteristics, suggesting potential for its utilization in developing functional emulsified meat products. In order to explore the effect of HDL addition on emulsification stability, rheological properties and structural features of myosin (MS) emulsions, HDL-MS emulsion was prepared by mixing soybean oil with isolated HDL and MS, with pH adjustments ranging from 3.0 to 11.0. The results found that emulsification activity and stability in two emulsion groups consistently improved as pH increased. Under identical pH, HDL-MS emulsion exhibited superior emulsification behavior as compared to MS emulsion. The HDL-MS emulsion under pH of 7.0-11.0 formed a viscoelastic protein layer at the interface, adsorbing more proteins and retarding oil droplet diffusion, leading to enhanced oxidative stability, compared to the MS emulsion. Raman spectroscopy analysis showed more flexible conformational changes in the HDL-MS emulsion. Microstructural observations corroborated these findings, showing a more uniform distribution of droplet sizes in the HDL-MS emulsion with smaller particle sizes. Overall, these determinations suggested that the addition of HDL enhanced the emulsification behavior of MS emulsions, and the composite emulsions demonstrated heightened responsiveness under alkaline conditions. This establishes a theoretical basis for the practical utilization of HDL in emulsified meat products.

A review of recent advances in the use of complex metal nanostructures for biomedical applications from diagnosis to treatment

Complex metal nanostructures represent an exceptional category of materials characterized by distinct morphologies and physicochemical properties. Nanostructures with shape anisotropies, such as nanorods, nanostars, nanocages, and nanoprisms, are particularly appealing due to their tunable surface plasmon resonances, controllable surface chemistries, and effective targeting capabilities. These complex nanostructures can absorb light in the near-infrared, enabling noteworthy applications in nanomedicine, molecular imaging, and biology. The engineering of targeting abilities through surface modifications involving ligands, antibodies, peptides, and other agents potentiates their effects. Recent years have witnessed the development of innovative structures with diverse compositions, expanding their applications in biomedicine. These applications encompass targeted imaging, surface-enhanced Raman spectroscopy, near-infrared II imaging, catalytic therapy, photothermal therapy, and cancer treatment. This review seeks to provide the nanomedicine community with a thorough and informative overview of the evolving landscape of complex metal nanoparticle research, with a specific emphasis on their roles in imaging, cancer therapy, infectious diseases, and biofilm treatment. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Diagnostic Tools > Diagnostic Nanodevices.

Effect of Nonprotein Components for Lipid Oxidation in Emulsions Stabilized by Plant Protein Extracts

Plant protein ingredients are rich in non-protein components of which the antioxidant and pro-oxidant effects are expected to be considerable. In this paper, commercial soy and pea protein isolates and concentrates were selected by using their soluble fractions to prepare oil-in-water (O/W) emulsions. Emulsions stabilized with soy protein isolates were more prone to lipid oxidation than those with soy protein concentrate or pea protein isolate. Compositional analysis revealed that the soluble fraction of soy protein isolates contained higher concentrations of phenolic compounds and metals (iron and copper) but lower mineral and ash contents than those of soy protein concentrate and pea protein isolate. Correlating the composition to oxidation in emulsions highlighted the significant role of non-protein components, alongside the protein's oxidative state. These findings are relevant for the use of alternative proteins in food formulation, a practice often promoted as sustainable yet that may come with repercussions for oxidative stability.

Lipid oxidation in emulsions: New insights from the past two decades

Lipid oxidation constitutes the main source of degradation of lipid-rich foods, including food emulsions. The complexity of the reactions at play combined with the increased demand from consumers for less processed and more natural foods result in additional challenges in controlling this phenomenon. This review provides an overview of the insights acquired over the past two decades on the understanding of lipid oxidation in oil-in-water (O/W) emulsions. After introducing the general structure of O/W emulsions and the classical mechanisms of lipid oxidation, the contribution of less studied oxidation products and the spatiotemporal resolution of these reactions will be discussed. We then highlight the impact of emulsion formulation on the mechanisms, taking into consideration the new trends in terms of emulsifiers as well as their own sensitivity to oxidation. Finally, novel antioxidant strategies that have emerged to meet the recent consumer's demand will be detailed. In an era defined by the pursuit of healthier, more natural, and sustainable food choices, a comprehensive understanding of lipid oxidation in emulsions is not only an academic quest, but also a crucial step towards meeting the evolving expectations of consumers and ensuring the quality and stability of lipid-rich food products.

Improving the storage and oxidative stability of essential fatty acids by different encapsulation methods; a review

Linoleic acid and α-linolenic acid are the only essential fatty acids (EFAs) known to the human body. Other fatty acids (FAs) of the omega-6 and omega-3 families originate from linoleic acid and α-linolenic acid, respectively, by the biological processes of elongation and desaturation. In diets with low fish consumption or vegetarianism, these FAs play an exclusive role in providing two crucial FAs for maintaining our body's vital functions; docosahexaenoic acid and arachidonic acid. However, these polyunsaturated FAs are inherently sensitive to oxidation, thereby adversely affecting the storage stability of oils containing them. In this study, we reviewed encapsulation as one of the promising solutions to increase the stability of EFAs. Accordingly, five main encapsulation techniques could be classified: (i) spray drying, (ii) freeze drying, (iii) emulsification, (iv) liposomal entrapment, and (v) other methods, including electrospinning/spraying, complex coacervation, etc. Among these, spray drying was the frequently applied technique for encapsulation of EFAs, followed by freeze dryers. In addition, maltodextrin and gum Arabic were the main wall materials in carriers. Paying attention to industrial scalability and lower cost of the encapsulation process by the other methods are the important aspects that should be given more attention in the future.

Evaluation of the Physical and Oxidative Stabilities of Fish Oil-in-Water-in-Olive Oil Double Emulsions (O1/W/O2) Stabilized with Whey Protein Hydrolysate

This work studied the physical and oxidative stabilities of fish oil-in-water-in-olive oil double emulsions (O₁/W/O₂), where whey protein hydrolysate was used as a hydrophilic emulsifier. A 20 wt.% fish oil-in-water emulsion, stabilized with whey protein hydrolysate (oil: protein ratio of 5:2 w/w) and with a zeta potential of ~-40 mV, only slightly increased its D_4,3 value during storage at 8 °C for seven days (from 0.725 to 0.897 µm), although it showed severe physical destabilization when stored at 25 °C for seven days (D_4,3 value increased from 0.706 to 9.035 µm). The oxidative stability of the 20 wt.% fish oil-in-water emulsion decreased when the storage temperature increased (25 vs. 8 °C) as indicated by peroxide and p-anisidine values, both in the presence or not of prooxidants (Fe²⁺). Confocal microscopy images confirmed the formation of 20 wt.% fish oil-in-water-in-olive oil (ratio 25:75 w/w) using Polyglycerol polyricinoleate (PGPR, 4 wt.%). Double emulsions were fairly physically stable for 7 days (both at 25 and 8 °C) (Turbiscan stability index, TSI < 4). Moreover, double emulsions had low peroxide (<7 meq O₂/kg oil) and p-anisidine (<7) values that did not increase during storage independently of the storage temperature (8 or 25 °C) and the presence or not of prooxidants (Fe²⁺), which denotes oxidative stability.