Oxidative Stability Of Fish Oil Research Articles

Synthesis and characterization of 3,4-dihydroxyphenyl acetic acid esters and study of their efficacy in bulk fish oil

Lipophilization of natural antioxidants is a proven strategy to enhance the solubility in bulk oil systems, thereby increasing their efficacy against oxidative degradation. This study aims to synthesize esters of 3,4-dihydroxyphenylacetic acid (3,4-DHPA) using Amberlyst-15 and to study the application of these esters in refined fish oil. Lipophilic esters were synthesized by esterification and transesterification of 3,4-DHPA in various solvent systems. Esters of methanol, butanol and hexanol were obtained with percent conversion of 81.1, 69.3 and 78.8 respectively, and were subjected to molecular characterization and in vitro oxidant assays. The 3,4-DHPA and its methyl ester showed 36% reduction in the TOTOX value over 30 days of storage. The length of the acyl chain in the ester was found to exert a high influence on its efficacy and lipophilicity. This is the first report of 3,4-DHPA and its lipophilic esters studied for enhancing the oxidative stability of fish oil.

Synthesis of triacetylferulic resveratrol ester and its assessment on the oxidative stability of fish oil during accelerated oxidative storage

A new antioxidant triacetylferulic resveratrol ester (TRE) was synthesized and characterized in the current research. The scavenging activity of TRE against 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) free radicals was carried out by comparison with tert-butylhydroxyquinone (TBHQ), ferulic acid and resveratrol. The inclusion of TRE as an oil stabilizer in fish oil was also investigated by assessing lipid oxidation parameters such as peroxide value (POV), TBARS value and p-anisidine value (pAV) under accelerated storage conditions (12 days, 80 °C). The changes in fatty acid composition were monitored by infrared spectroscopy and gas chromatography–mass spectrometry. The results showed that the oxidation stability of fish oil supplemented with TRE was better than that of fish oil containing TBHQ, ferulic acid and resveratrol during the whole storage period. Further, the formation of oxidation products in fish oil followed a first-order kinetic model, and adding TRE effectively lowered down the reaction rate constants. Therefore, TRE can be used as a strong antioxidant for tackling oxidative processes.

Antioxidative properties of fish roe peptides combined with polyphenol on the fish oil oleogel.

This study aimed to investigate the effects of large yellow croaker (Larimichthys crocea) roe protein hydrolysate (LYCPH)-polyphenol (catechin (CA), gallic acid (GA), and tannic acid (TA)) conjugates on the oxidative stability of fish oil in an oleogel system. Scanning electron microscopy and Fourier transform infrared spectroscopy suggested that the LYCPH-polyphenol conjugates were nearly spherical and non-covalent and that covalent effects could coexist between LYCPH and polyphenols. LYCPH-TA exhibited the highest ABTS scavenging, reducing capacities, and emulsifying stability. Raman spectra and chemometrics revealed that LYCPH-TA loaded with oleogels had the best oxidative stability. Additionally, 32 volatile compounds were identified in fish oil by headspace gas chromatography-ion mobility spectrometry. Overall, this study demonstrated that fish oil oleogels loaded with LYCPH-polyphenol conjugates could inhibit fish oil oxidation. © 2022 Society of Chemical Industry.

The Potential of Phaeodactylum as a Natural Source of Antioxidants for Fish Oil Stabilization.

Worldwide, fish oil is an important and rich source of the health-beneficial omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA). It is, however, troubled by its high susceptibility towards lipid oxidation. This can be prevented by the addition of (preferably natural) antioxidants. The current research investigates the potential of Phaeodactylum carotenoids in this regard. The oxidative stability of fish oil and fish oil with Phaeodactylum addition is evaluated by analyzing both primary (PV) and secondary (volatiles) oxidation products in an accelerated storage experiment (37 °C). A first experimental set-up shows that the addition of 2.5% (w/w) Phaeodactylum biomass is not capable of inhibiting oxidation. Although carotenoids from the Phaeodactylum biomass are measured in the fish oil phase, their presence does not suffice. In a second, more elucidating experimental set-up, fish oil is mixed in different proportions with a Phaeodactylum total lipid extract, and oxidative stability is again evaluated. It was shown that the amount of carotenoids relative to the n-3 LC-PUFA content determined oxidative stability. Systems with a fucoxanthin/n-3 LC-PUFA ratio ≥ 0.101 shows extreme oxidative stability, while systems with a fucoxanthin/n-3 LC-PUFA ratio ≤ 0.0078 are extremely oxidatively unstable. This explains why the Phaeodactylum biomass addition did not induce oxidative stability.

Fish oil encapsulated in soy protein particles by lyophilization. Effect of drying process

Fish oil is an important source of healthy ω-3 fatty acids to be used in functional foods. However, its autoxidation susceptibility, aroma and solubility make it difficult to use. Its encapsulation could reduce these disadvantages. This manuscript focuses on the drying stage of the encapsulation process. Its objective was to study the encapsulation of fish oil with soy proteins by emulsification and lyophilization and compare microparticles characteristics with those processed identically but spray dried. Microparticles with different protein/oil ratios were prepared by emulsification and lyophilization. Soy proteins encapsulated fish oil in matrix-type microcapsules masking its typical odor and oily appearance. Microparticles dried by lyophilization showed a better solid recovery but lower encapsulation efficiency than those spray dried. Increasing protein/oil mass ratio of initial formulations seemed to favor initial lipid oxidation, but these differences were not appreciated when analyzing the oxidative stability over time (measured by Rancimat test). Porous structure and large surface area of lyophilized samples would favor oxygen easy penetration and exposition to free radicals, increasing lipid oxidation over time, while spray dried microparticles showed a good oxidative stability over time, like that of free oil. Drying processes were determinants in the morphology of microcapsules, the efficiency of encapsulation and protection exerted on the oil. Although emulsifying and drying processes caused certain initial oil oxidation, soy proteins managed to mask fish oil flavors and spray dried systems showed a good perspective of oxidative stability of fish oil over time, better than that of lyophilized microparticles. © 2021 Society of Chemical Industry.

Pumpkin oil addition and encapsulation process as methods to improve oxidative stability of fish oil

Although seafood is an important part of a healthy and balanced diet, many humans do not consume the recommended amounts of fish or other marine products possibly due to the fishy smell and taste of the products. The aim of this study was to compare the sensory properties and oxidative stability of capsules made of fish liver oil rich in eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic (DHA, 22:6n-3) acids with capsules made of blend of fish liver oil and thick and dark green pumpkin oil with a nutty aroma and high content of native antioxidants. Sensory quality and oxidative stability of capsules prepared using different coating materials (maltodextrin, whey, sunflower and rice proteins and guar gum) were compared. Blending fish liver oil with pumpkin oil diminished the share of EPA and DHA in the prepared blend, but enriched it in tocopherols, carotenoids, squalene and enhanced almost to 2-fold the oxidative stability. Further growth of oxidative stability (by almost 5-fold) was observed after encapsulation process. Blended oil encapsulated with rice proteins had the least intense fishy and rancid odours and fishy flavour.

Stability of Fish Oil in Calcium Alginate Microcapsules Cross-Linked by In Situ Internal Gelation During Spray Drying

Microencapsulating bioactive compounds, such as polyunsaturated fatty acids (PUFA), in dry cross-linked alginate serves to enhance their shelf life, mask unwanted flavors and odors, facilitate their incorporation into food products, and provide an intestinal release mechanism. Alginate microencapsulation is challenging to implement at industrial scale, but a recently developed process provides scalability by accomplishing alginate cross-linking in situ during spray drying. This study investigated how formulation variables affect the oxidative stability of fish oil in cross-linked alginate microcapsules (CLAMs) prepared via this industrially scalable process. Storage stability of PUFA from fish oil was prolonged by microencapsulation in CLAMs, relative to nonencapsulated fish oil. Neither the choice of emulsifier (Tween 80 or whey protein isolate) nor the extent of alginate cross-linking influenced the duration of storage stability of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). However, the retention of EPA and DHA during spray drying was significantly lower for CLAMs prepared with Tween 80. The addition of n-octenyl succinic anhydride (OSA) modified starch into spray-drying formulations improved the storage stability of microencapsulated fish oil. With increasing OSA-starch content in CLAMs, surface oil content decreased, particle size and powder yield increased, and PUFA storage stability increased. Despite OSA-starch being the majority component, OSA-starch CLAMs exhibited gastrointestinal release properties more akin to CLAMs than control OSA-starch microcapsules. OSA-starch CLAMs retained fish oil cargo in simulated gastric fluid and released it in simulated intestinal fluid, while OSA-starch microcapsules completely released cargo in either fluid. Overall, OSA-starch CLAMs show promise as an industrial-scale system for stabilizing PUFA while providing an enteric delivery mechanism.

Combination of internal structuring and external coating in an oleogel-based delivery system for fish oil stabilization.

In this study, we created oleogel-based formulations featuring varying degrees of beeswax for internal structure and whey protein isolate (WPI) as external coating to improve the oxidative stability of fish oil. Oleogel was characterized by rheological analysis to access gelation behavior, and morphology was visualized using electron microscopy. It was found that the WPI-coated oleogel displayed strong physical stability during storage. The oxidative assay demonstrated that WPI-coated oleogel had the best protection against fish oil oxidation under both thermal treatment and ultraviolet-C radiation. The oxidation of fish oil was inhibited by 2-3 fold, compared to its unencapsulated form. This stability was attributed to the modulation of beeswax and WPI on the micropolarity and microviscosity of the formulation, as evidenced by pyrene fluorescence measurement. Our approach combining internal structuring and external coating may contribute to the development of oleogel system for efficient delivery of lipophilic bioactive components.

Effects of Low Temperature Solvent Fractionation on the Thermal Oxidative Stability and Antioxidant Activity of Refined Hoki Oil and its Derived Fractions

Thermal oxidative stability of refined hoki oil (RHO) and its fractions obtained via low temperature solvent crystallization (LTSC) are carried out using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) by isothermal and programmed heating. In the LTSC method, the sample is dissolved with hexane at a ratio of 1:4 (w/v). Results show the induction time for thermal change occurrs earlier in the TGA than the DSC as the oil gains weight due to oxygen uptake prior to heat release during decomposition. The onset time for oxidation of the liquid fraction (RHOL) occurs earlier than its parent oil (RHO) and solid fraction (RHOS) during isothermal heating due to the high amount of polyunsaturated fatty acid (PUFA) content. Thermal decomposition of RHO and its fractions occur at three stages which indicates the progressive degradation of fatty acids, followed by volatilization of polymerization and pyrolysis products. Thermal decomposition pattern of RHOL is similar to RHO and RHOS, however, the starting temperature of thermal decomposition of RHOL is significantly lower (120.60 °C) than RHO (139.91 °C). The vitamins A and E in RHOL are higher than RHOS but the antioxidant activity (ABTS and DPPH) of these two oils is not significantly different since the increased amount of PUFA in RHOL made it more susceptible to oxidation.Practical Applications: Fish oil has been used as a raw material for omega‐3 fatty acid concentrates production that can be incorporated into food and pharmaceutical products. LTSC method is used to concentrate the omega‐3 fatty acids in the fish oils. The liquid fraction obtained from the LTSC method contains more unsaturated fatty acids compared to the parent oil and its solid fraction. However, it is more prone to oxidation and can affect the acceptability of food products fortified with fish oil. Information on the oxidative stability of fish oil is useful to food manufacturers to optimize processing conditions and for prediction of shelf life of food products fortified with fish oil. DSC and TGA have been used as instrumental methods for measuring the oxidative stability of oils. These methods offer a simple and rapid measurement for oxidative stability of oils compared to traditional chemical and physical oxidative stability methods.Oxidative stability of refined hoki oil (RHO) and its fractions obtained via low temperature solvent crystallization are measured using differential scanning calorimetry (top part of the figure) and themogravimetric analysis (bottom part of the figure). The oxidation onset time of the liquid and solid fractions of RHO are earlier than the parent oil. The liquid fraction of RHO is less stable to heat compared to RHO parent oil and its solid fraction due to its high PUFA content. In contrast, the solid fraction of RHO is less stable than RHO parent oil because it contains less vitamins A and E compared to RHO parent oil and its liquid fraction.

The use of factorial design to evaluate the oxidation of oils containing different types of omega-3 fatty acids.

Omega-3 fatty acids (n3 FA) promote beneficial effects on cardiovascular diseases, but they are highly susceptible to oxidation, which leads to the formation of potentially toxic secondary products. In this study, the antioxidant capacity of natural compounds (sinapic acid and rutin) was evaluated using an accelerated model to oxidize the oils. Five inducers (temperature, Fe2+ , 2,2'-azobis(2-amidinopropane) dihydrochloride, ascorbyl palmitate and the hydrophobic 2,2'-azobis-2,4-dimethylvaleronitrile (AMVN)) were combined in a factorial design to accelerate the oxidation of three oils (flaxseed, echium and fish) containing different sources of n3 FA. Lipid hydroperoxide (LOOH) and thiobarbituric acid reactive substance (TBARS) concentrations estimated using the regression models did not differ from the observed values. AMVN + Fe2+ increased TBARS in all samples. The values for the oxidative markers obtained 48 h after induction were similar to those obtained when the oils were heated at 60 ° C for 15 days. Of a number of volatile compounds formed from the oxidation of different n3 FA sources, (E,E)-2,4-heptadienal, (E,E)-2,4-decadienal, decanal, undecanal and (E)-2-undecenal were identified in all samples and could be used as more specific oxidative markers. Using the accelerated model, rutin improved the oxidative stability of fish oil, probably due to the presence of a catechol group in its chemical structure. © 2017 Society of Chemical Industry.

Improving oxidative stability of liquid fish oil supplements for pets

Omega‐3 polyunsaturated fatty acids have produced beneficial health effects in animals and are recommended by veterinaries to pet patients suffering from osteoarthritis. However, these oils are highly susceptible to lipid oxidation. The objectives of this study were to improve oxidative stability of fish oil by adding vegetable oils, mixed tocopherols and rosemary extract, and to formulate a commercial product according to the results obtained. The formulated product was evaluated against commercial fish oil products. An initial screening for antioxidative effect was performed by using Oxipres equipment. The effect of antioxidant and vegetable oil blends was examined in oils stored at 30 and 40°C by measuring peroxide value, volatile compounds with GC‐MS and tocopherol content. Addition of vegetable oil and rosemary extract at high level (4000–6000 ppm) plus 600 ppm of mixed tocopherols increased oxidative stability to the same extent as 2000 ppm mixed tocopherols in Oxipres. Overall, oxidative stability of fish oil or fish oil + vegetable oil blends was improved the most by addition of 5000 ppm rosemary extract and 500 ppm mixed tocopherols. A commercial oil blend with composition optimized based on the results of this study performed better than other commercial marine oils tested.Practical applications: In some commercial oil blends for pets, a high level of vegetable oils is included in order to increase oxidative stability. In this study, vegetable oils are included at 30% level. At this level of vegetable oil inclusion, the omega‐3 EPA and DHA content of the blends is at least 21% of total fatty acids for both fish and tuna oil based blends. In this study we wanted to examine, whether we could reduce the level of vegetable oil inclusion without compromising oxidative stability. This study demonstrates how the oxidative stability of omega‐3 PUFA formulations for pets can be improved by combining fish oil with vegetable oils and by adding an antioxidant blend consisting of high concentrations of rosemary extract and tocopherol. The results are also of relevance to the manufacturers of dietary supplements.

Curcumin and its two analogues improve oxidative stability of fish oil under long‐term storage

Adding antioxidant is one of the most effective ways to prevent oil systems from oxidation. Curcumin (Cur) and its derivatives have a significant antioxidant activity as potential antioxidants. In this work, the oxidative stability of fish oil treated with three different concentrations (0.1, 0.2 and 0.3 mg/g) of Cur, its two synthetic analogues (compounds 14 and 25) and α‐tocopherol (positive control) are determined after 70 days at 4 and 25 °C. The antioxidants are evaluated by acid (AV), peroxide (PV), conjugated diene (CD) values, thiobarbituric acid‐reactive substances (TBARS) as well as polyunsaturated fatty acid (PUFA) in fish oil. Results show that Cur and α‐tocopherol could protect fish oil from oxidation more effectively than compound 14 and 25 at 4 °C, whereas compound 14 and 25 could protect fish oil from oxidation more effectively than Cur and α‐tocopherol at 25 °C. Temperature is an important factor on lipid oxidation in the process of fish oil storage resulted from antioxidant activity of compounds determined by temperature. Curcumin shows the decreased ability to protect fish oil from oxidation with increasing temperature. Compounds 14 and 25 show increasing ability to protect fish oil from oxidation with increasing temperature.Practical applications: Compounds 14 and 25 are potential antioxidants to extend expiration date of the fish oil product.Temperature is a key variable for fish oil storage. Compounds 14 and 25 show higher biological stability than that of Curcumin. In long‐term storage at 25 °C, compounds 14 and 25 perform better antioxidant activity in fish oil than Curcumin, and tocopherol.

Effect of gelatin/agar bilayer film incorporated with TiO2 nanoparticles as a UV absorbent on fish oil photooxidation

AbstractThis research evaluated the effect of gelatin/agar bilayer film and nanocomposites containing different concentrations of TiO2 nanoparticles (0.5%, 1% and 2%) as ultraviolet (UV) and oxygen barriers on the oxidative stability of fish oil. Samples of fish oil covered with the bilayer films were stored under UV light or in darkness and with or without lids at 18 °C for 12 days. Oil quality in terms of peroxide values (PV), thiobarbituric acid (TBA), conjugated diene (CD), fatty acids profile and colour change (∆E) was monitored during storage. Fish oil photooxidation was hindered by increasing TiO2 concentration, so that nanocomposite containing 2% of the nanoparticles could control photooxidation, similar to the samples stored in darkness. Furthermore, upon studying both photooxidation and autoxidation, the highest amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), as well as the lowest amount of changes in PV, TBA, CD and ∆E, were observed in oils covered with the nanocomposites.

Effect of different dextrose equivalents of maltodextrin on oxidation stability in encapsulated fish oil by spray drying

Encapsulating fish oil by spray drying with an adequate wall material was investigated to determine if stable powders containing emulsified fish-oil-droplets can be formed. In particular, the dextrose equivalent (DE) of maltodextrin (MD) affects the powder structure, surface-oil ratio, and oxidative stability of fish oil. The carrier solution was prepared using MD with different DEs (DE=11, 19, and 25) and sodium caseinate as the wall material and the emulsifier, respectively. The percentage of microcapsules having a vacuole was 73, 39, and 38% for MD with DE=11, 19, and 25, respectively. Peroxide values (PVs) were measured for the microcapsules incubated at 60°C. The microcapsules prepared with MD of DE=25 and 19 had lower PVs than those prepared with MD of DE=11. The difference in PV can be ascribed to the difference in the surface-oil ratio of the spray-dried microcapsules.

Physicochemical Property and Oxidative Stability of Whey Protein Concentrate Multiple Nanoemulsion Containing Fish Oil.

The objectives of this research were to produce whey protein concentrate (WPC) multiple nanoemulsion (MNE) and to study how whey protein concentration level and antioxidant type affected the physicochemical properties and oxidative stability of fish oil in MNE. The morphological and physicochemical characteristics of MNE were investigated by using transmission electron microscopy and particle size analyzer, respectively. The oxidative stability of fish oil in MNEs was assessed by measuring peroxide value (PV), p-anisidine value, and volatile compounds. The spherical forms of emulsions with size ranging from 190 to 210nm were observed indicating the successful production of MNE. Compared with free fish oil, fish oil in MNE exhibited lower PV, p-anisidine value, and formation of maker of oxidation of fish oil indicating the oxidative stability of fish oil in MNE was enhanced. PV, p-anisidine value, and makers of oxidation of fish oil were decreased with increased WPC concentration level. The combined use of Vitamin C and E in MNE resulted in a reduction in PV and p-anisidine value, and development of maker of oxidation. In conclusion, WPC concentration level and antioxidant type are key factors affecting the droplet size of MNE and oxidative stability of fish oil.

Effect of Crystalline Structure on Oxidation of Fish Oil in Stearin:Fish Oil Mixtures

Effects of incorporation of stearin fraction into fish oil on crystallisation behaviour and oxidative stability of fish oil were examined. The stearin fraction (S25) was obtained from step-wise dry fractionation of anhydrous milk fat at 25 °C. Analysis of fatty acid composition by gas chromatography showed that unsaturated fatty acids (89.3 %) were enriched in the fish oil whereas the S25 typically comprises of saturated fatty acids (79.4 %). A series of S25:fish oil mixtures (0:100, 25:75, 50:50, 75:25; 90:10 and 100:0) was prepared by mixing the S25 and fish oil at 50 °C under flushing of nitrogen gas. Crystallisation and thermal properties and crystal structures of the mixtures were investigated by differential scanning calorimetry and small- and wide-angle X-ray scattering, respectively. The crystallisation/melting temperatures and crystallisation/melting enthalpies of the mixtures increased with increasing ratios of S25 blended into fish oil. All mixtures showed similar crystal structures (double- and triple-chain length) and crystal polymorphs (α, β’ and β) at 4 °C. A decrease in S25 fraction in the mixtures caused a higher proportion of triple-chain length crystal packing and β polymorph. Measurement of peroxide values of the mixtures upon storage at 8 °C for 42 days showed that blending as low as 25 % S25 sufficiently delayed the lipid oxidation of fish oil by about two-fold and the rancidity threshold to 16 days instead of 9 days for fish oil only. This study demonstrates that mobility of oxygen and triacylglycerol (TAG) molecules in fish oil can be restricted by crystalline state of milk fat, in turn, limiting the propagation of oxidative reaction in fish oil.

Thermal oxidative stability analysis of hoki and tuna oils by Differential Scanning Calorimetry and Thermogravimetry

In this study, oxidative stability of hoki and tuna oils were measured at 80°C by Differential Scanning Calorimetry (DSC) and thermogravimetric analysis (TGA) under an air atmosphere. The onset time for oxidation (to) of hoki oil occurred earlier in the TGA (222.50 min) compared to DSC (640.83 min) as the sample gained weight prior to decomposition. Conversely, the to of tuna oil could not be recorded since tuna oil was rapidly oxidized. The predicted shelf life of hoki oil for onset of oxygen uptake and subsequent decomposition at 4°C, by Arrhenius extrapolation of TGA and DSC under different isothermal treatments were 0.56 and 1.39 years, respectively. Temperature programmed decomposition of hoki and tuna oils by TGA occurred in three thermal stages, suggesting a progressive degradation of polyunsaturated fatty acids (PUFA), monounsaturated fatty acids (MUFA), and saturated fatty acids (SFA), followed by volatilization of polymerization and pyrolysis products.Practical applications: Fish oil has been marketed as dietary supplements and as an ingredient for food products. However, these products are susceptible to oxidation due to the high‐PUFA content in fish oil. Oxidative and thermal stability of fish oil are important parameters in the processing and production of fish oil and fish oil fortified food products. These data can be used by fish oil and food manufacturers to optimize processing conditions for fish oil and food products fortified with fish oil. The oxidative stability of fish oils over temperature ranges and storage times can be measured by both isothermal and non‐isothermal DSC and TGA analyses. These techniques are more rapid and provide continuous data compared to conventional shelf life studies and alternative instrumental methods. Shelf life of the fish oils can be predicted by an Arrhenius extrapolation from elevated isothermal DSC and TGA analyses.Measurement of oxidative stability of fish oils by DSC and TGA follow the Q10 law on the relationship between temperature and rate of chemical reaction. Prediction of shelf life of the fish oils is possible by an Arrhenius extrapolation from elevated isothermal DSC and TGA analyses. Differences in the thermal behavior of the fish oils were consistent with major fatty acid compositional differences.

Oxidative stability during storage of fish oil from filleting by‐products of rainbow trout (Oncorhynchus mykiss) is largely independent of the processing and production temperature

Rainbow trout (Oncorhynchus mykiss) is the main fish species produced in Danish fresh water farming. Large amounts of fileting by‐products like heads, bones, tails (HBT), and intestines are produced when rainbow trout is processed to smoked rainbow trout filets. The filleting by‐products can be used to produce high quality fish oil. In this study, the oxidative stability of fish oil produced from filleting by‐products was evaluated. The oil was produced from conventional or organic fish (low and high omega‐3 fatty acid content) at different temperatures (70 and 90°C). The oxidative stability of the oil was tested during storage at two different temperatures (20 and 40°C). Results showed that omega‐3 content of the fish oil influenced the oxidative stability, whereas the processing temperature during oil production played a minor role.Practical applications: The fish oil used for this study was produced in industrial scale. Hence, this research is highly relevant for companies and academics that are working with fish oil extraction and fish oil oxidative stability.The oxidative stability of crude fish oil extracted at two different temperatures from conventional and organic rainbow trout was investigated during storage at 20°C and 40°C and linked to the oil production temperature.

Assessment of the Antioxidant Effects ofMoringa oleiferaLam. Extracts in Fish Oil during Storage

This study assessed the antioxidant activity of Moringa oleifera Lam. extracts on the oxidative stability of fish oil subjected to conditions of accelerate storage (16 days at 60C) compared with synthetic antioxidants such as tertiary butylhydroquinone (TBHQ) and butylated hydroxytoluene (BHT). Fish oil samples were added with leaves, flowers and seed pod extracts and evaluated for peroxide, hydroperoxides, anisidine and conjugated diene values. Changes in trans-fatty acid and aldehyde content were also assessed. The addition of Moringa extracts delayed the oxidation of fish oil; in particular, extracts of leaves showed a higher antioxidant activity when compared with TBHQ and BHT, considering peroxide and hydroperoxide levels. To control the formation of secondary oxidation compounds, synthetic antioxidants were most effective; however, leaf extract showed the highest protective effects of polyunsaturated fatty content in fish oil. Results indicate that the extract of M. oleifera leaves is an effective antioxidant to prevent oxidation in fish oil. Practical Applications Antioxidants are important ingredients in food processing to retard, reduce or prevent oxidative deterioration. Synthetic antioxidants are widely used in the food industry; however, their utilization has been questioned because of toxicity. Therefore, there is a growing interest in the use of natural antioxidants to reduce or replace the synthetic antioxidants in edible oils. Moringa oleifera L. is a botanical specie that is well known for its rich compounds with high antioxidant activity; in particular, its leaf extract can be used to replace synthetic antioxidants used in fish oil.

Prosopis alba exudate gum as excipient for improving fish oil stability in alginate–chitosan beads

The aim of the present work was to employ an exudate gum obtained from a South American wild tree (Prosopis alba), as wall material component to enhance the oxidative stability of fish oil encapsulated in alginate–chitosan beads. For this purpose, beads were vacuum-dried and stored under controlled conditions. Oxidation products, fatty acid profiles and lipid health indices were measured during storage. Alginate–chitosan interactions and the effect of gum were manifested in the FT-IR spectra. The inclusion of the gum in the gelation media allowed decreasing the oxidative damage during storage in comparison to the free oil and alginate–chitosan beads. The gum also improved wall material properties, providing higher oil retention during the drying step and subsequent storage. Fatty acids quality and lipid health indices were widely preserved in beads containing the gum. Present results showed a positive influence of the gum on oil encapsulation and stability, being the main mechanism attributed to a physical barrier effect.