Examination of marine and vegetable oil oxidation data from a multi-year, third-party database

Investigating the impact of wet rendering (solventless method) on PUFA-rich oil from catfish (Clarias magur) viscera

Catfish (Clarias magur) is a popular freshwater fish food worldwide. The processing of this fish generates a significant amount of waste, mainly in the form of viscera, which constitutes around 10-12% of the fish's total weight. This study was focused on extracting polyunsaturated fatty acid (PUFA)-rich oil from catfish viscera, aiming to enhance the extraction process and make the production of oil and handling of fish byproducts more cost-effective. The wet reduction method, a solvent-free approach, was used for extraction, with yield optimization done via the Box-Behnken design. The resulting oil was evaluated for its oxidative quality and chemical characteristics. The optimal conditions for the wet rendering process were as follows: viscera to water ratio, 1:0.5 (w/v); temperature, 90℃; and time, 20 min, yielding 12.40 g/100 g of oil. The oil extracted under optimal wet rendering conditions had quality and oxidative stability comparable to solvent extraction and fewer secondary oxidation compounds. This oil had a higher PUFA content, specifically a 4:1 ratio of omega 6 to omega 3. Such oil, derived from catfish viscera, is suitable for the food industry due to its solvent-free extraction method.

Predigested Mixture of Arachidonic and Docosahexaenoic Acids for Better Bio-Accessibility

A predigested product from arachidonic acid oil (ARA) and docosahexaenoic acid (DHA) oil in a 2:1 (w/w) ratio has been developed and evaluated in an in vitro digestion model. To produce this predigested lipid mixture, first, the two oils were enzymatically hydrolyzed up to 90% of free fatty acids (FFAs) were achieved. Then, these two fatty acid (FA) mixtures were mixed in a 2:1 ARA-to-DHA ratio (w/w) and enzymatically esterified with glycerol to produce a mixture of FFAs, mono-, di-, and triacylglycerides. Different glycerol ratios and temperatures were evaluated. The best results were attained at 10 °C and a glycerol-to-FA molar ratio of 3:1. The bio-accessibility of this predigested mixture was studied in an in vitro digestion model. A total of 90% of the digestion product was found in the micellar phase, which contained 30% monoacylglycerides, more than 50% FFAs, and a very small amount of triacylglycerols (3% w/w). All these data indicate an excellent bio-accessibility of this predigested mixture.

Predicting Antioxidant Synergism via Artificial Intelligence and Benchtop Data

Lipid oxidation is a major issue affecting products containing unsaturated fatty acids as ingredients or components, leading to the formation of low molecular weight species with diverse functional groups that impart off-odors and off-flavors. Aiming to control this process, antioxidants are commonly added to these products, often deployed as combinations of two or more compounds, a strategy that allows for lowering the amount used while boosting the total antioxidant capacity of the formulation. While this approach allows for minimizing the potential organoleptic and toxic effects of these compounds, predicting how these mixtures of antioxidants will behave has traditionally been one of the most challenging tasks, often leading to simple additive, antagonistic, or synergistic effects. Approaches to understanding these interactions have been predominantly empirically driven but thus far, inefficient and unable to account for the complexity and multifaceted nature of antioxidant responses. To address this current gap in knowledge, we describe the use of an artificial intelligence model based on deep learning architecture to predict the type of interaction (synergistic, additive, and antagonistic) of antioxidant combinations. Here, each mixture was associated with a combination index value (CI) and used as input for our model, which was challenged against a test (n = 140) data set. Despite the encouraging preliminary results, this algorithm failed to provide accurate predictions of oxidation experiments performed in-house using binary mixtures of phenolic antioxidants and a lard sample. To overcome this problem, the AI algorithm was then enhanced with various amounts of experimental data (antioxidant power data assessed by the TBARS assay), demonstrating the importance of having chemically relevant experimental data to enhance the model's performance and provide suitable predictions with statistical relevance. We believe the proposed method could be used as an auxiliary tool in benchmark analysis routines, offering a novel strategy to enable broader and more rational predictions related to the behavior of antioxidant mixtures.

Combination of Dehydration and Expeller as a Novel Methodology for the Production of Olive Oil

An alternative olive oil (OO) production process has been developed based on the combination of olive dehydration, followed by extraction with an expeller press. This procedure eliminates the utilization of water and avoids the malaxation stage. Hence, no water residues are generated. In this study, the mentioned alternative methodology was compared to conventional extraction methods. High extraction yields and oil recovery were obtained with our novel procedure. On the contrary, substantial percentages of by-products were generated with conventional methodology. The quality indexes (acidity and peroxide values) of the oils obtained by the combination of dehydration and expeller (dOO) were 0.4% of oleic acid and 3 meq O2/kg of oil, respectively. Furthermore, none of the applied processes affected the resulting OO's fatty acid composition and lipid profile. Total phenolic content was up to four times higher for dOO than for other olive oils and it showed resistance to oxidation with an oxidative stability index about five times higher than that for conventional olive oils.

A Multi-Year Rancidity Analysis of 72 Marine and Microalgal Oil Omega-3 Supplements

There exists significant heterogeneity in the 'freshness' of consumer marine- and plant-derived omega-3 (Ω3) supplements. Fears of rancidity, or the oxidation of consumer Ω3 supplements, has been debated in the literature with several prior authors reporting contradictory findings. We report the peroxide value (PV), para-anisidine value (p-AV) and total oxidation values (TOTOX) associated with 72 consumer Ω3 supplements sold in the United States sampled from 2014-2020. The effect of flavoring on the oxidation of the supplements was examined in an adjusted fixed effects model controlling for type of delivery system (enteric, liquid, animal- and vegetable-derived gelatin softgel, spray), source (algae, calamari, fish, krill, mussels), and certifications assigned by third-party organizations (e.g. USP). Overall, our results revealed that 68% (23/34) of flavored and 13% (5/38) unflavored consumer Ω3 supplements exceeded the TOTOX upper limit set by the Global Organization for EPA and DHA (GOED) voluntary monograph standard of ≤ 26, with 65% (22/34) flavored supplements and 32% (12/38) unflavored supplements failing the PV upper limit of ≤ 5 and 62% (21/34) flavored supplements exceeding the p-AV upper limit of ≤ 20. To our knowledge, no prior authors have modeled the impact of flavoring on oxidative status in 72 marine- and plant-derived Ω3 products sold in the U.S. We present our findings in this context and discuss the clinical implications related to the consumption of oxidized consumer fish oils and their effects on human health.

Effect of packaging and encapsulation on the oxidative and sensory stability of omega-3 supplements

Omega-3 fatty acid consumption is getting more common due to its positive impacts on human health. Since consumers cannot get their omega-3 needs from natural sources, omega-3-rich products play an essential part in the diet. However, they are highly susceptible to oxidation; thus, storage conditions affect their quality. Product form is also another critical factor for stability. In this study, fatty acid composition, oxidative stability, and sensory properties of different omega-3 products having varied packaging types were investigated. Moreover, the effect of consumer behavior regarding the recommended usage was assessed during storage. Syrup forms (maximum values at the end of the storage: PV = 44.6 meq/kg oil for S32, p-AV = 16.87 for S22, and TOTOX = 96.94 for S11) are more susceptible to oxidation than capsule (maximum values at the end of the storage: PV = 7.62 meq/kg oil for C31, p-AV = 19.58 for C12, and TOTOX = 30.44 for C12) and chewable forms (maximum values at the end of the storage: PV = 26.14 meq/kg oil for G12, p-AV = 13.47 for G12, and TOTOX = 65.76 for G12). In addition, capsules complied more with limit values during storage and were better protected according to the sensory scores. The aroma and taste of the omega-3 products generally changed in a negative manner during storage. Capsulated samples were better protected according to the sensory evaluation scores at the end of the storage period. Fish oil samples belonging to the same company but provided from different stores showed significant differences, which is an indicator of nonstandard raw material, ingredient, or processing.

Comprehensive Analysis of Fatty Acid and Oxylipin Patterns in n3-PUFA Supplements

Supplementing long-chain omega-3 polyunsaturated fatty acids (n3-PUFA) improves health. We characterized the pattern of total and non-esterified oxylipins and fatty acids in n3 supplements made of fish, krill, or micro-algae oil by LC-MS. All supplements contained the declared amount of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); however, their content per capsule and the concentration of other fatty acids varied strongly. Krill oil contained the highest total n3 oxylipin concentration (6000 nmol/g) and the highest degree of oxidation (EPA 0.7%; DHA 1.3%), while micro-algae oil (Schizochytrium sp.) showed the lowest oxidation (<0.09%). These oils contain specifically high amounts of the terminal hydroxylation product of EPA (20-HEPE, 300 nmol/g) and DHA (22-HDHA, 200 nmol/g), which can serve as an authenticity marker for micro-algae oil. Refined micro-algae and fish oil were characterized by NEFA levels of ≤0.1%. Overall, the oxylipin and fatty acid pattern allows gaining new insights into the origin and quality of n3-PUFA oils in supplements.

Flaxseed oil and palm olein blend to improve omega-6: omega-3 ratio

The objective of the study was to develop the oil blend with improved omega-6 to omega-3 fatty acid ratio (ω-6:ω-3) with good oxidative and thermal stability. Flaxseed oil and palm olein were selected for the blending. Flaxseed oil is rich in anti-inflammatory omega-3 fatty acid (ω-3 FA) but is oxidatively very unstable. Palm olein has low omega-6 fatty acid content and high thermal and oxidative stability. Blends containing various percent (v/v) of flaxseed oil and palm olein were prepared. Oxidative and thermal stability was determined by analyzing peroxide value, acid value, smoke point, % free fatty acids, para-Anisidine and TOTOX values. Nutritive quality was confirmed by determining fatty acid composition. Nine month storage stability of the blend containing highest flaxseed oil percentage was assessed in terms of peroxide and acid value and fatty acid composition. The biological effects were studied in THP-1 cell line as the effect on cell survival, FA uptake and inflammatory markers. The data indicates that, blending improved ω-6:ω-3 ratio. Oxidative and thermal stability study, and nine month storage stability study suggested that palm olein imparted stability to the blend. Fatty acid profiles of the cells treated with these blends showed uptake of Alpha Linolenic Acid (ω-3 FA). These blends lowered inflammatory TNFα level without affecting cell survival. Thus, blending of flaxseed oil with palm olein may result in better health benefits owing to their improved nutritional and stability properties.

Optimisation of Healthy-Lipid Content and Oxidative Stability during Oil Extraction from Squid (Illex argentinus) Viscera by Green Processing

Green extraction was applied to Argentinean shortfin squid (Illex argentinus) viscera, consisting of a wet pressing method including a drying step, mechanic pressing, centrifugation of the resulting slurry, and oil collection. To maximise the oil yield and ω3 fatty acid content and to minimise the oil damage degree, a response surface methodology (RSM) design was developed focused on the drying temperature (45-85 °C) and time (30-90 min). In general, an increase of the drying time and temperature provided an increase in the lipid yield recovery from the viscera. The strongest drying conditions showed a higher recovery than 50% when compared with the traditional chemical method. The docosahexaenoic and eicosapentaenoic acid contents in the extracted oil revealed scarce dependence on drying conditions, showing valuable ranges (149.2-166.5 and 88.7-102.4 g·kg^-1 oil, respectively). Furthermore, the values of free fatty acids, peroxides, conjugated dienes, and ω3/ω6 ratio did not show extensive differences by comparing oils obtained from the different drying conditions. Contrary, a polyene index (PI) decrease was detected with increasing drying time and temperature. The RSM analysis indicated that optimised drying time (41.3 min) and temperature (85 °C) conditions would lead to 74.73 g·kg^-1 (oil yield), 1.87 (PI), and 6.72 (peroxide value) scores, with a 0.67 desirability value.

Letter to the editor regarding "Omega-3 fats in pregnancy: could a targeted approach lead to better metabolic health for children?"

The purpose of our letter to the editor is to offer additional perspective regarding 4 statements that do not fully represent the totality of the available scientific evidence. The 4 statements are as follows: (1) "Multiple studies have shown that n-3 PUFA products frequently have less n-3 PUFA content than labelled"; (2) "Recently, krill oil supplementation was shown to induce insulin resistance, indicating that it is potentially harmful"; (3) "… fish oil products are frequently oxidized at the time of purchase"; and (4) "In rats, supplementation with oxidized fish oil during pregnancy induced persistent maternal insulin resistance and increased neonatal mortality rate." We respectfully request the authors' future publications consider the totality of the available scientific evidence.

Response to Bannenburg and Rice

This manuscript is a response to concerns expressed in a letter by industry-based scientists Bannenburg and Rice in response to our recent narrative review. In the review, we largely discussed why supplementation with n-3 PUFA rich oils might have benefits to the body composition and metabolism of the offspring of overweight or obese pregnant women. Bannenburg and Rice raised concerns about a number of points that may be perceived as negative about the quality and functionality of commercial fish oils. We provide a refutation to their comments and a brief review of recent evidence regarding the n-3 PUFA content, and oxidative state of supplements available to consumers. From a clinical research perspective, there remains a need to exercise caution. An oil containing less n-3 PUFAs than expected may be ineffective, and lead to incorrect conclusions that n-3 PUFAs lack efficacy. Oxidized fish oil may be ineffective or even cause unwanted harm. Although we must not overinterpret limited evidence from animal models, we have a responsibility to minimize risk to study participants, especially those most vulnerable, such as pregnant women. Prior to selecting a fish oil to be used in a clinical trial, it is essential to independently verify the n-3 PUFA content of the oil, and that the oil is unoxidized.

Synthesis of EPA- and DHA-Enriched Structured Acylglycerols at the sn-2 Position Starting from Commercial Salmon Oil by Enzymatic Lipase Catalysis under Supercritical Conditions

There is consistent evidence that long-chain polyunsaturated fatty acids (LCPUFA) belonging to the n-3 series, i.e., eicosapentaenoic (20:5n-3, EPA) and docosahexaenoic (22:6n-3, DHA) acids, decrease the risk of heart, circulatory and inflammatory diseases. Furthermore, the bioavailability of such fatty acids has been shown to depend on their location in triacylglycerol (TG) molecules at the sn-2 position. Consequently, great attention has been accorded to the synthesis of structured acylglycerols (sAG), which include EPA or DHA at the sn-2 position. The aim of this work was to synthesize sAG starting from deodorized refined commercial salmon oil. For this, immobilized lipase B from Candida antarctica (nonspecific) was used as a catalyst for the intra–interesterification process under CO₂ supercritical conditions (CO₂SC). According to the CO₂SC reaction time, three different fractions including sAG compounds were obtained. The location of EPA and DHA at the sn-2 position in the resulting glycerol backbone was identified by mass spectrometry (MALDI-TOF) analysis. In all fractions obtained, a marked decrease in the starting TG content was observed, while an increase in the DHA content at the sn-2 position was detected. The fraction obtained after the longest reaction time period (2 h) led to the highest yield of sn-2 position DHA in the resulting sAG molecule.

Optimum Processing Conditions for Bakasang Using the Response Surface Methodology with Central Composite Design (CCD)

&lt;b&gt;Background and Objective:&lt;/b&gt; Bakasang is a typical food of North Sulawesi and its surroundings, made from fermented fish viscera. This food is made by fermentation so that it is rich in amino acids and polypeptides. This study aimed to determine the optimum processing conditions for Bakasang with Peroxide Value (PV) parameters based on Response Surface Methodology (RSM) with Central Composite Design (CCD). &lt;b&gt;Materials and Methods:&lt;/b&gt; Viscera from fresh Skipjack tuna consisting of intestines, liver, heart and eggs were mixed with salt and left in a fermenter for varying times and temperatures to obtain Bakasang. The fermentation temperature, salt content, and fermentation time, determined based on the Central Composite Design (CCD), were variables in this study. Thus, 20 experiments consisted of eight quadratic points, six centre points and six axial points. &lt;b&gt;Results:&lt;/b&gt; The results showed that the correlation test between temperature, salinity and fermentation time variables on PV were 0.521, 0.305 and 0.591. The regression test resulted in an R&lt;sup&gt;2&lt;/sup&gt; value of 0.988. The model equation obtained was y = 4.35194 - 0.11363x&lt;sub&gt;1 &lt;/sub&gt;- 0.07459x&lt;sub&gt;2 &lt;/sub&gt;- 0.25300x&lt;sub&gt;3 &lt;/sub&gt;+ 0.00157x&lt;sub&gt;12 &lt;/sub&gt;+ 0.00310x&lt;sub&gt;22&lt;/sub&gt; + 0.01571x&lt;sub&gt;32&lt;/sub&gt; - 0.00064x&lt;sub&gt;1&lt;/sub&gt;x&lt;sub&gt;2 &lt;/sub&gt;+ 0.00172x&lt;sub&gt;1&lt;/sub&gt;x&lt;sub&gt;3&lt;/sub&gt; + 0.00340x&lt;sub&gt;2&lt;/sub&gt;x&lt;sub&gt;3&lt;/sub&gt;. The contour plot graph obtained from the experiment using CCD showed that the optimum processing conditions for Bakasang were at a temperature of 32.9324°C, salinity 10.2631% and fermentation time of 4.7793 days, which will produce Bakasang with an optimum PV of 1.51256 meq kg&lt;sup&gt;1&lt;/sup&gt; sample. &lt;b&gt;Conclusion:&lt;/b&gt; According to the findings of this study, the optimum temperature, salinity and fermentation time for producing Bakasang with a PV of 1.51256 meq kg&lt;sup&gt;1&lt;/sup&gt; sample were 32.932°C, 10.263% and 4.779 days, respectively.

Chemical Compositional Changes in Over-Oxidized Fish Oils

A recent study has reported that the administration during gestation of a highly rancid hoki liver oil, obtained by oxidation through sustained exposure to oxygen gas and incident light for 30 days, causes newborn mortality in rats. This effect was attributed to lipid hydroperoxides formed in the omega-3 long-chain polyunsaturated fatty acid-rich oil, while other chemical changes in the damaged oil were overlooked. In the present study, the oxidation condition employed to damage the hoki liver oil was replicated, and the extreme rancidity was confirmed. A detailed analysis of temporal chemical changes resulting from the sustained oxidative challenge involved measures of eicosapentaenoic acid/docosahexaenoic acid (EPA/DHA) omega-3 oil oxidative quality (peroxide value, para-anisidine value, total oxidation number, acid value, oligomers, antioxidant content, and induction time) as well as changes in fatty acid content, volatiles, isoprostanoids, and oxysterols. The chemical description was extended to refined anchovy oil, which is a more representative ingredient oil used in omega-3 finished products. The present study also analyzed the effects of a different oxidation method involving thermal exposure in the dark in contact with air, which is an oxidation condition that is more relevant to retail products. The two oils had different susceptibility to the oxidation conditions, resulting in distinct chemical oxidation signatures that were determined primarily by antioxidant protection as well as specific methodological aspects of the applied oxidative conditions. Unique isoprostanoids and oxysterols were formed in the over-oxidized fish oils, which are discussed in light of their potential biological activities.

Concentration of EPA and DHA from Refined Salmon Oil by Optimizing the Urea⁻Fatty Acid Adduction Reaction Conditions Using Response Surface Methodology

This research focused on obtaining eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3) (EPA+DHA) concentrates from refined commercial salmon oil (RCSO). Independent variables of the complexation process were optimized by means of the application of response surface methodology (RSM) in order to obtain the maximum content of such fatty acids (FAs). As a result of employing the optimized conditions for all the variables (6.0, urea:FA content ratio; -18.0 °C, crystallization temperature; 14.80 h, crystallization time; 500 rpm, stirring speed), high contents of EPA and DHA could be obtained from RCSO, achieving increases of 4.1 and 7.9 times in the concentrate, with values of 31.20 and 49.31 g/100 g total FA, respectively. Furthermore, a 5.8-time increase was observed for the EPA + DHA content, which increased from 13.78 to 80.51 g/100 g total FA. It is concluded that RCSO can be transformed into a profitable source of EPA and DHA (EPA+DHA), thus leading to a product with higher commercial value.

Combined impacts of oregano extract and vacuum packaging on the quality changes of frigate tuna muscles stored at 3±1°C

Aim

The combined effects of oregano extract with vacuum packing (VP) on the quality enhancement of dark and white muscles of frigate tuna (Auxis thazard) stored as intact fillet at refrigerated (3±1°C) conditions were studied.

Materials and Methods

About 35 kg of fish were filleted without skin removal and randomly divided into two groups. One group without treatment (control) and the remaining group were dipped in a sterilized oregano extract solution for 5 min. Chemical, microbiological, sensorial, and textural analyses were carried out in each of dark and white muscles of frigate tuna fillets during storage.

Results

Several quality indexes were higher in dark muscle than white muscle. The sensory assessment indicated that both muscles from control had a shelf life of 12 days. Quality parameters of both muscles had the same tendency and were significantly affected by time and also by the presence of plant extract in VP. Although VP alone was sufficient to delay lipid oxidation on fish fillets, especially on dark muscle but cannot enhance the textural deterioration in both muscles.

Conclusion

Consequently, the employment of such combination had a cumulative effect on preservation, resulting in prolonging the shelf life of both frigate tuna muscles.