Natural antioxidants enhance the oxidation stability of blended oils enriched in unsaturated fatty acids.

BACKGROUND: Rancidity causes unpleasant tastes and smells, and the degradation of fatty acids and natural antioxidants, so that an oil is unfit to be consumed. Natural antioxidants, including tocopherols, polyphenols (sesamol, canolol, ferulic acid, caffeic acid, etc.), ß-carotene, squalene and phytosterols, contribute to delay the oxidation of vegetable oils. However, studies on the combination of natural antioxidants to lengthen the shelf life of unsaturated fatty acid-rich blended oil have not been reported. RESULTS: All of the composite antioxidants had the potential to significantly improve the oxidation stability of blended oil. Blended oil G with 0.05 g kg-1 ß-carotene, 0.25 g kg-1 sesamol and 0.25 g kg-1 caffeic acid showed the best anti-autooxidation. It is also effective in improving the oxidative stability of vegetable oils containing various fatty acids. The oxidation stability index of the blended oil containing the optimum composition of natural antioxidants was 2.17-fold longer than that of the control sample. After the end of accelerated oxidation, the oil's peroxide value, p-anisidine value and total oxidation value were 6.59 times, 12.26 times and 6.65 times lower than those of the control sample, respectively. CONCLUSION: (1) The combination of natural antioxidants ß-carotene (0.05 g kg-1 ), sesamol (0.25 g kg-1 ) and caffeic acid (0.25 g kg-1 ) enhances the oxidative stability of unsaturated fatty acid-rich blended oils. (2) ß-Carotene is the main antioxidant in the early stages of oxidation. (3) Sesamol and caffeic acid are the main antioxidants in the middle and late stages of oxidation. © 2023 Society of Chemical Industry.

Nitrogen-Doped Titanium Carbide (Ti3 C2 Tx ) MXene Nanosheet Stack For Long-Term Stability and Efficacy in Au and Ag Recovery.

The development of efficient adsorbents for the practical recovery of precious metals from electronic waste is vital to advanced energy/environment industries. Ti3 C2 Tx MXene-based materials are promising adsorbents for aqueous environments; however, the highly defective and super hydrophilic nature of the MXene surface hinders its practical applications. Here, we report that nitrogen-doped MXene (N-MXene) nanosheet stacks, prepared via high-energy planetary ball milling under N2 purging, exhibited a long-term stable and excellent recovery capability for Au and Ag ions via the nitrogenation of defective vacancies. Notably, these microscale nanosheets could facilitate the sustainable production of Au and Ag from secondary sources, exhibiting a high recovery rate and capability (1198 mg g-1 for Au and 1528 mg g-1 for Ag), long-term stable storability (21 d), and high selectivity (Kd of 1.67 × 106 for Au and 2.07 × 107 for Ag). Furthermore, the reversible redox chemistry of N-MXene facilitated its repeated use in adsorption/desorption cycles.

Novel high-oleic oil consumption for cardiometabolic health: a narrative review.

Several cardiometabolic disorders are risk factors for cardiovascular diseases (CVDs), and prevention is imperative in reducing the burden of these diseases on the healthcare system. Although novel high-oleic acid oils (HOOs) are now commonly used for high-temperature frying in both foodservice and the manufacture of processed foods, there are still limited data regarding their effects on CVD risk. This narrative review aims to clarify these effects by comparing HOOs with saturated fatty acid (SFA)-rich and polyunsaturated fatty acid (PUFA)-rich oils, first regarding their physicochemical properties and then concerning their effects on CVD risk factors using recent randomized controlled trials (RCTs). Overall, although HOOs are more stable than PUFA-rich oils, they do not have the same high-temperature stability as SFA-rich oils. RCTs demonstrate that HOO consumption improves the plasma lipid profile compared with SFA-rich oils while showing similar effects to those of PUFA-rich oils on CVD risk factors. Finally, the current literature lacks information on the actual consumption of HOOs, their long-term effects on cardiometabolic health, and the impact of prolonged heating of these oils on CVD risk factors. In sum, the short-term intake of HOOs may be beneficial for cardiometabolic health; however, more research is needed.

Amide/Amino-Based Functional Additives for Lubricants: Structure, Antimicrobial Activity and Wear Resistance.

The lubricating properties of the lubricants were tested under boundary friction conditions; it was found that the surface-active additives had reduced the wear mark and thus the value of the Goz/40 parameter (limiting load of wear). The introduction of a surfactant containing amide compounds into the oils and greases was highly effective in slowing down the oxidation process. Lubricants containing mono-15 ([3-(N,N,N-dimethylbuthylamine)propyl]hexadecanamide chloride) and 15-4-15 (tetramethylene-bis [3-(N,N,N-dimethylamine)propyl]hexadecanamide) additives were characterised by higher oxidation stability compared to the unmodified lubricants. Both of the analysed substances showed bactericidal properties against Staphylococcus aureus and Salmonella enteritica. Tests of antibacterial activity in the lubricants with the addition of mono-15 and 15-4-15 confirmed that these lubricants can be considered bactericidal against Gram-positive and Gram-negative bacteria.

Highly Valuable Fish Oil: Formation Process, Enrichment, Subsequent Utilization, and Storage of Eicosapentaenoic Acid Ethyl Esters.

In recent years, as the demand for precision nutrition is continuously increasing, scientific studies have shown that high-purity eicosapentaenoic acid ethyl ester (EPA-EE) functions more efficiently than mixed omega-3 polyunsaturated fatty acid preparations in diseases such as hyperlipidemia, heart disease, major depression, and heart disease; therefore, the market demand for EPA-EE is growing by the day. In this paper, we attempt to review EPA-EE from a whole-manufacturing-chain perspective. First, the extraction, refining, and ethanolysis processes (fish oil and ethanol undergo transesterification) of EPA-EE are described, emphasizing the potential of green substitute technologies. Then, the method of EPA enrichment is thoroughly detailed, the pros and cons of different methods are compared, and current developments in monomer production techniques are addressed. Finally, a summary of current advanced strategies for dealing with the low oxidative stability and low bioavailability of EPA-EE is presented. In conclusion, understanding the entire production process of EPA-EE will enable us to govern each step from a macro perspective and accomplish the best use of EPA-EE in a more cost-effective and environmentally friendly way.

Oxidative removal of fluorescent components from soil DOM and its effect on heavy metals around abandoned mining areas.

The oxidation stability of soil organic matter (SOM) plays an important role in the environmental chemical behavior of heavy metals (HMs). In this study, the oxidation stability of SOM and soil dissolved organic matter (DOM) for four soils around the mining area in Western China, including grassland (GR), forest land (FR), farmland soil (FA), and mining area soil (MA), was investigated. The oxidation effect of fluorescent DOM (FDOM) was determined by using synchronous fluorescence spectroscopy (SFS). The results showed that the oxidation stability of SOM for four soils follows the order: MA > GR > FR > FA. Protein-like fluorescence (A2) is dominant in soil DOM, more than 96% of which were more easily degraded. As the wavelength increases, FDOM components become more difficult to oxidize. Second derivative, two-dimensional correlation spectroscopy (2D-COS) and 1/n power transformation can identify more FDOM components, protein-like materials can be preferential removal by the oxidation process, followed by humic-like substances. The oxidation process increased the release of Cr, Cu, Zn, Pb and Fe in FA soil. Therefore, the oxidation stability of SOM and FDOM can affect the immobilization and release of HMs, and this work provides scientific guidance for remediation of soil HMs around abandoned mining areas.

Unveiling the Critical Role of Ion Coordination Configuration of Ether Electrolytes for High Voltage Lithium Metal Batteries.

Albeit ethers are favorable electrolyte solvents for lithium (Li) metal anode, their inferior oxidation stability (<4.0 V vs. Li/Li+ ) is problematic for high-voltage cathodes. Studies of ether electrolytes have been focusing on the archetype glyme structure with ethylene oxide moieties. Herein, we unveil the crucial effect of ion coordination configuration on oxidation stability by varying the ether backbone structure. The designed 1,3-dimethoxypropane (DMP, C3) forms a unique six-membered chelating complex with Li+ , whose stronger solvating ability suppresses oxidation side reactions. In addition, the favored hydrogen transfer reaction between C3 and anion induces a dramatic enrichment of LiF (a total atomic ratio of 76.7 %) on the cathode surface. As a result, the C3-based electrolyte enables greatly improved cycling of nickel-rich cathodes under 4.7 V. This study offers fundamental insights into rational electrolyte design for developing high-energy-density batteries.

Electrochemical determination of several biofuel antioxidants in biodiesel and biokerosene using polylactic acid loaded with carbon black within 3D-printed devices.

Low oxidation stability is the main drawback of biodiesels and biokerosenes that is overcome by using antioxidants, which can be combined due to synergistic effects. This paper demonstrates that 3D-printed electrochemical devices can be applied to biofuel electroanalysis, including the monitoring of oxidation stability by quantifying the antioxidant content in biofuels. Fabrication requires 3D-printed acrylic templates at which a polylactic acid (PLA) filament with conducting carbon-black filling sensors is extruded by a 3D pen. The antioxidants butyl hydroxyanisole (BHA) and tert-butylhydroquinone (TBHQ) are the most employed additives in biodiesel production, and thus, their electrochemical behavior was investigated; 2,6-ditertbutylphenol (2,6-DTBP) was included in this investigation because it is commonly added to biokerosenes. The electrochemical surface treatment of the 3D-printed electrodes improved the current responses of all antioxidants; however, the electrochemical oxidation of TBHQ was clearly more affected by an electrocatalytic action shifting its oxidation towards less positive potentials (~200 mV), which resulted in a better separation of TBHQ and BHA oxidation peaks (+0.4 and +0.6 V vs Ag|AgCl, respectively). The oxidation of 2,6-DTBP occurred at more positive potentials (+1.2 V vs Ag|AgCl). The simultaneous determination of TBHQ and BHA by differential-pulse voltammetry resulted in linear responses in the range 0.5 and 175 µmol L-1 with limits of detection and quantification of 0.15 µmol L-1 and 0.5 µmol L-1, respectively. The presence of Fe3+, Cu2+, Pb2+, Mn2+, Cd2+, and Zn2+, even in high concentrations, did not interfere in the determination of TBHQ and BHA. The determination of 2,6-DTBP in biokerosene was achieved by cyclic voltammetry. All relative standard deviations (RSD) were lower than 6.0 %, indicating adequate precision of the methods. Spiked biofuel samples were analyzed (after dilution in electrolyte) and recovery values between 85 and 120% were obtained, which indicates absence of sample matrix effects.

Stable Lead-Free Tin Halide Perovskite with Operational Stability >1200 h by Suppressing Tin(II) Oxidation.

Sn-based perovskites are the most promising alternative materials for Pb-based perovskites to address the toxicity problem of lead. However, the development of SnII -based perovskites has been hindered by their extreme instability. Here, we synthesized efficient and stable lead-free Cs4 SnBr6 perovskite by using SnF2 as tin source instead of easily oxidized SnBr2 . The SnF2 configures a fluorine-rich environment, which can not only suppress the oxidation of Sn2+ in the synthesis, but also construct chemically stable Sn-F coordination to hinder the electron transfer from Sn2+ to oxygen within the long-term operation process. The SnF2 -derived Cs4 SnBr6 perovskite shows a high photoluminescence quantum yield of 62.8 %, and excellent stability against oxygen, moisture, and light radiation for 1200 h, representing one of the most stable lead-free perovskites. The results pave a new pathway to enhance the optical properties and stability of lead-free perovskite for high-performance light emitters.

An investigation of the effect of temperature on the oxidation processes of metallic diesel engine fuel system materials and B100 biodiesel from used cooking oil in exposure testing.

Biodiesel is increasingly being used in automotive and other engine applications because of its potential to contribute to the reduction of CO2 and other harmful emissions. However, biodiesel is known to be more corrosive in contact with metallic components than petroleum diesel. This work explores the corrosion of aluminium, steel, brass and copper metallic coupons exposed to B100 biodiesel at 25, 80, 90, 100, 110 and 120 °C. The metals that were chosen are commonly found in automotive engines. The B100 in each experiment was sampled at 48, 100, 150, 200 and 270 h and examined by GCMS to determine compositional changes. It was found that corrosion rates for copper were 10x faster than brass and approximately 100x faster than for mild steel, Al7075 and Al1050. Activation energies for corrosion were calculated from mass loss and ICP, with good correlation between the two methods for Cu containing samples. By mass loss, the activation energies for Cu, Brass, Al7075 and Al1050 were calculated to be -47.9 kJ mol-1, -85.4 kJ mol-1, -86.7 kJ mol-1 and -54.4 kJ mol-1, respectively. By ICP analysis, the activation energies for Cu, Brass, and Al7075 were calculated to be -57.9 kJ mol-1, -90 kJ mol-1 and -140 kJ mol-1, respectively. Corrosion rates in brass and copper samples were faster owing to the direct reaction of copper with the fatty acid. The copper was found to cause chain scission and greater degradation of the biodiesel.

Thermal-Oxidation Stability of Soybean Germ Phytosterols in Different Lipid Matrixes.

The stability of soybean germ phytosterols (SGPs) in different lipid matrixes, including soybean germ oil, olive oil, and lard, was studied at 120, 150, and 180 °C. Results on the loss rate demonstrated that SGPs were most stable in olive oil, followed by soybean germ oil, and lard in a decreasing order. It is most likely that unsaturated fatty acids could oxidize first, compete with consumption of oxygen, and then spare phytosterols from oxidation. The oxidation products of SGPS in non-oil and oil systems were also quantified. The results demonstrated that at relatively lower temperatures (120 and 150 °C), SGPs' oxidation products were produced the most in the non-oil system, followed by lard, soybean germ oil, and olive oil. This was consistent with the loss rate pattern of SGPs. At a relatively higher temperature of 180 °C, the formation of SGPs' oxidation products in soybean germ oil was quantitatively the same as that in lard, implying that the temperature became a dominative factor rather than the content of unsaturated fatty acids of lipid matrixes in the oxidation of SGPs.

Preparation and Characterization of Octenyl Succinate ß-Cyclodextrin and Vitamin E Inclusion Complex and Its Application in Emulsion.

Vitamin E (VE) and ß-cyclodextrin (ß-CD) can form an inclusion complex; however, the inclusion rate is low because of the weak interaction between VE and ß-CD. The results of a molecular docking study showed that the oxygen atom in the five-membered ring of octenyl succinic anhydride (OSA) formed a strong hydrogen bond interaction (1.89 Å) with the hydrogen atom in the hydroxyl group of C-6. Therefore, ß-CD was modified using OSA to produce octenyl succinic-ß-cyclodextrin (OCD). The inclusion complexes were then prepared using OCD with VE. The properties of the inclusion complex were investigated by Fourier-transform infrared spectroscopy (FT-IR), 13C CP/MAS NMR, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The results demonstrated that VE had been embedded into the cavity of OCD. Furthermore, the emulsifying properties (particle size distribution, ζ-potential, and creaming index) of the OCD/VE inclusion-complex-stabilized emulsion were compared with that stabilized by ß-CD, OCD, and an OCD/VE physical mixture. The results showed that the introduction of the OS group and VE could improve the physical stability of the emulsion. In addition, the OCD/VE inclusion complex showed the strongest ability to protect the oil in the emulsion from oxidation. OCD/VE inclusion complex was able to improve the physical and oxidative stability of the emulsion, which is of great significance to the food industry.

Anion Solvation Reconfiguration Enables High-Voltage Carbonate Electrolytes for Stable Zn/Graphite Cells.

Conventional carbonate solvents with low HOMO levels are theoretically compatible with the low-cost, high-voltage chemistry of Zn/graphite batteries. However, the nucleophilic attack of the anion on carbonates induces an oxidative breakdown at high potentials. Here, we restore the inherent anodic stability of carbonate electrolytes by designing a micro-heterogeneous anion solvation network. Based on the addition of a strongly electron-donating solvent, trimethyl phosphate (TMP), the oxidation-vulnerable anion-carbonate affinities are decoupled because of the preferential sequestration of anions into solvating TMP domains around the metal cations. The hybridized electrolytes elevate the electrochemical window of carbonate electrolytes by 0.45 V and enable the operation of Zn/graphite dual-ion cells at 2.80 V with a long cycle life (92 % capacity retention after 1000 cycles). By inheriting the non-flammability from TMP and the high ion-transport kinetics from the carbonate systems, this facile strategy provides cells with the additional benefits of fire retardancy and high-power capability.

Impact of linolenic acid on oxidative stability of rapeseed oils.

The objective of this study was to investigate the effects of linolenic acid (LA) on oxidation stability of rapeseed oils. Four kinds of rapeseed were harvested by unified cultivation and management in the same geographical conditions, and then four rapeseed oils with different contents of LA were obtained. The effects of linolenic acid and antioxidants (tocopherols and phytosterols) on oxidation stability of rapeseed oils were evaluated. Results showed that rapeseed oil with 5.9% LA was the most stable among four rapeseed oils, followed by commercial rapeseed oil, rapeseed oil with 8.4% LA and rapeseed oil with 10.8% LA. The oxidation stability was negatively correlated with the contents of LA (r = - 0.931, p < 0.01), the polyunsaturated fatty acids (r = - 0.932, p < 0.01), and unsaturated fatty acids (r = - 0.766, p < 0.05). It had no correlation with tocopherols and phytosterols (p > 0.05). In addition, according to the European Union Standards, shelf-life of four rapeseed oils was longer than 30 days in the shelf-life test. Therefore, increasing the LA content in rapeseed oils can be considered as an efficient approach to solve the problem of insufficient LA intake globally.

Comparative study on the characteristics and oxidation stability of commercial milk powder during storage.

The quality of milk powder can decrease during storage. In this study, the characteristics of 12 kinds of commercial milk powder from China were investigated. Changes in various indicators were tracked to comprehensively estimate the oxidation stability of different commercial milk powders. The components of the commercial milk powder were different. The percentages of milk fat, protein, and carbohydrates ranged from 9.8 to 28.5 g/100 g, 15.0 to 24.0 g/100 g, and 32.0 to 67.5 g/100 g, respectively. The water activities ranged from 0.2394 to 0.5286. The diameters of the milk fat globules in different commercial milk powder ranged from 13.99 to 41.09 nm. At the same time, the peroxide value of the control sample was low (≤0.14 mEq/kg). After 3 mo of storage, the peroxide values of some of the commercial milk powder increased significantly. The changes in the thiobarbituric acid values during storage did not follow a common trend. The contents of free fat in the different control samples were 0.21 to 1.67 g/100 g, and these values did not increase during storage. After 3 mo of storage, the hydroxymethyl furfural values and b color values of the different commercial milk powder reached their highest levels. The concentrations of typical oxidized flavor compounds in different commercial milk powder increased greatly with prolonged storage time. The level of hexanal was the highest, and the contents in all the samples ranged from 28.56 to 4,071.28 µg/kg after 6 mo of storage and from 5.91 to 6,281.37 µg/kg after 12 mo of storage. Free radicals were found in some of the stored milk powder, and these were shown as single peaks or multiple peaks. The ratios of the peak areas and masses reached 12.42 × 106 to 14.26 × 108. However, the presence of free radicals in the commercial milk powder was not consistent. The water activities and diameters of the fat globules in the commercial milk powder were highly correlated with their oxidation stabilities during storage.

Supramolecular Carotenoid Complexes of Enhanced Solubility and Stability-The Way of Bioavailability Improvement.

Carotenoids are natural dyes and antioxidants widely used in food processing and in therapeutic formulations. However, their practical application is restricted by their high sensitivity to external factors such as heat, light, oxygen, metal ions and processing conditions, as well as by extremely low water solubility. Various approaches have been developed to overcome these problems. In particular, it was demonstrated that application of supramolecular complexes of "host-guest" type with water-soluble nanoparticles allows minimizing the abovementioned disadvantages. From this point of view, nanoencapsulation of carotenoids is an effective strategy to improve their stability during storage and food processing. Also, nanoencapsulation enhances bioavailability of carotenoids via modulating their release kinetics from the delivery system, influencing the solubility and absorption. In the present paper, we present the state of the art of carotenoid nanoencapsulation and summarize the data obtained during last five years on preparation, analysis and reactivity of carotenoids encapsulated into various nanoparticles. The possible mechanisms of carotenoids bioavailability enhancement by multifunctional delivery systems are also discussed.

Different levels of selenomethionine on the meat quality and selenium deposition in tissue of finishing pigs.

The aim of the study was to verify the influence of selenomethionine (SM) supplementation on performance, carcass yield, characteristics of meat quality and Se tissue deposition of finishing pigs. A total of 128 hybrid pigs with an average weight of 76 kg were distributed in randomized blocks according to body weight in eight treatments and eight replicates. The experimental treatments were two Se levels from sodium selenite-SS (0.3 and 0.6 ppm), four Se levels from SM (0.3, 0.4, 0.5 and 0.6 ppm) and two combinations of SS with SM (SS 0.15 + SM 0.15 ppm and SS 0.3 + SM 0.3 ppm) providing 0.3 and 0.6 ppm Se in the diet respectively. The feeds were based on corn and soya bean meal. After 30 days on test, were analysed the performance indices and the pigs were slaughtered at commercial slaughterhouse. The cold carcass yield, the physicochemical characteristics of the loin meat and the Se content in muscle and liver were evaluated. There was no significant difference in performance indices (p > .05); however, there was a linear effect on the increase in pig carcass yield by increasing SM (p < .05). The use of SM solely or combined with SS provided higher Se deposition in muscle compared to SS (p < .05). The highest Se deposition in muscle occurred for SM at 0.4 ppm (p < .05). The SS provided higher Se deposition in liver (p < .05). The SM presented best results for meat quality compared to other sources (p < .05). The level of 0.4 ppm Se promoted the best results for the indices of yellow, luminosity, cooking loss and pH (p < .05). The use of SM at any level promotes higher oxidation stability of pig meat (p < .05). The supplementation of SM at a level of 0.4 ppm promotes better physicochemical characteristics and higher Se deposition on swine meat.

Microwave-assisted extraction of hempseed oil: studying and comparing of fatty acid composition, antioxidant activity, physiochemical and thermal properties with Soxhlet extraction.

This work aimed to investigate the effects of the microwave-assisted extraction (MAE) on the hempseed (Cannabis sativa L.) oil yield, oxidation stability, and antioxidant activity. Power (300, 450, and 600 W) and time (5, 10, and 15 min) were independent variables while oil extraction yield, peroxide value (PV), p-anisidine value (AV), TOTOX value (TV), and DPPH scavenging activity were considered as dependent ones. Optimization was conducted by response surface methodology where the optimum point was 450 W and 7.19 min. In this point, the extraction yield obtained 33.91% w/w and the oil showed acceptable oxidation quality (PV of 2.5 meq/kg, AV of 0.67, and TV of 5.67) and antioxidant activity with the IC50 value of 30.82 mg/mL. The Soxhlet extraction (SE) method was carried out to be compared with MAE. It showed relatively higher oil extraction yield (37.93% w/w) but lower oil oxidation stability with PV of 6.4 meq/kg, AV of 3.69, TV of 16.49, and higher amount of IC50 32.47 mg/mL which showed lower antioxidant activity. Any significant difference between fatty acid compositions was not observed with the dominant amounts of linoleic acid and α-linolenic acid. Also, the tocopherol contents and thermal properties were studied by HPLC and DSC, respectively. MAE showed higher total tocopherol content (929.67 mg/kg) than SE (832.61 mg/kg) and γ-tocopherol was dominant. Moreover, DSC analysis showed that both profiles (crystallization and melting transitions) are likely influenced mostly by the triglyceride compositions and crystals structure.

Effect of liver pâté enrichment with flaxseed oil and flaxseed extract on lipid composition and stability.

BACKGROUND: There is an increase interest from food technologists in the improvement of the nutritional value of meat products, especially their lipid profile and shelf life. The aim of this study was to determine the effect of animal fat replacement with flaxseed oil (20%) and flaxseed extract addition (0.05%-0.25%) on changes in composition and stability of liver pâté lipid fractions. RESULTS: Replacement of animal fat with flaxseed oil was observed to lower the saturated and monoenoic fatty acid in the product's fatty acid profile by around 12% and to raise the polyene fatty acid contribution by more than 70% when compared to the control. The replacement also resulted in enriching the pâté with phytosterols (ß-sitosterol, campesterol, and cycloartenol). The addition of 0.05% and 0.10% ethanol flaxseed extract significantly slowed down lipid oxidation changes during storage of the pâté. CONCLUSIONS: The study showed that a storage-stable meat product - liver pâté - characterized by a high nutritional value can be designed through the addition of flax oil rich in unsaturated fatty acids and flaxseed extract. The addition of 0.05% of the extract was found to be sufficient to improve the liver pâté's oxidative stability; it can thus be recommended for this type of product. © 2018 Society of Chemical Industry.

Multilayer emulsions as a strategy for linseed oil and α-lipoic acid micro-encapsulation: study on preparation and in vitro characterization.

BACKGROUND: Linseed oil and α-lipoic acid are bioactive ingredients, which play an important role in human nutrition and health. However, their application in functional foods is limited because of their instabilities and poor solubilities in hydrophilic matrices. Multilayer emulsions are particularly useful to protect encapsulated bioactive ingredients. The aim of this study was to fabricate multilayer emulsions by a high-pressure homogenization method to encapsulate linseed oil and α-lipoic acid simultaneously. Tween 20 and lecithin were used as surfactants to stabilize the oil droplets of primary emulsions. Multilayer emulsions were produced by using an electrostatic layer-by-layer deposition process of lecithin-chitosan membranes. RESULTS: Thermal treatment exhibited that chitosan encapsulation could improve the thermal stability of primary emulsions. During in vitro digestion, it was found that chitosan encapsulation had little effect on the lipolysis of linseed oil and bioaccessibility of α-lipoic acid. The oxidation stability of linseed oil in multilayer emulsions was improved effectively by chitosan encapsulation and α-lipoic acid. Chitosan encapsulation could inhibit the degradation of α-lipoic acid. A physical stability study indicated that multilayer emulsions had good centrifugal, dilution and storage stabilities. CONCLUSION: Multilayer emulsion is an effective delivery system to incorporate linseed oil and α-lipoic acid into functional foods and beverages. © 2018 Society of Chemical Industry.