Tuna Oil Research Articles

Demand Elasticities of Canned Tuna at Point of Sale of a Large Retail Chain in Southern Philippines: Implications for Sustainability Policy

New variants of canned skipjack tuna have been developed by large manufacturers of canned tuna in the Philippines. This study analyzes the expenditure and price elasticities of canned tuna and determines the implications for sustainable fishery. An AIDS (almost ideal demand system) model incorporating an income group variable was used to estimate these elasticities. This study utilized a pooled time series data of 459 weekly point-of-sale observations from 2010–2012 of three store branches of a large supermarket chain in southern Philippines. The point-of-sale data suggest that canned tuna consumption is composed mostly of tuna in sauce with vegetables followed by tuna in oil and tuna in sauce without vegetables. For both high- and low-income groups, the expenditure elasticities have the expected positive signs – indicating that as the income of consumers’ increases, the quantity demanded for canned tuna in three product mediums also increases. For high-income consumers, consumption of tuna in sauce with and without vegetables is more responsive to income changes. The own-price elasticities of the three product mediums across high- and low-income store branches have negative signs – suggesting that as their own price increases, the quantity demanded for these products decreases. The cross-price elasticities suggest that tuna in sauce with vegetables is a substitute for tuna in oil and in sauce without vegetables for both income groups. Thus, promoting more use of vegetables through product development may lead to a lower volume of tuna meat used in canned tuna products, which contributes to addressing tuna resource sustainability

Cardiac contractile dysfunction, during and following ischaemia, is attenuated by low-dose dietary fish oil in rats.

Supplementing animal diets with high-dose fish oil, rich in long chain omega-3 (ω-3) docosahexaenoic acid (DHA), enhances cardiac contractile efficiency and attenuates dysfunction, attributable to ischaemia. However, it remains unclear whether smaller doses, equivalent to what is achievable via regular fish consumption in the human diet, offer similar protection. Male Sprague-Dawley (12-15w) rats were fed isoenergetic diets (ad libitum) containing 10% fat by weight (22% energy) for 4-5w. Control diet (CON) contained 5.5% beef tallow; 2.5% ω-6 sunflower seed oil; 2% olive oil. Fish oil diets included high-DHA tuna oil exchanged for olive oil to provide 0.32% (FO1; human equivalent EPA + DHA 570mg/d) or 1.25% (FO2; equivalent EPA + DHA 2.3g/d) wt/wt dose of fish oil. Anaesthetised rats (pentobarbital: 60mg/kg i.p.) were subjected to 45min coronary artery occlusion then reperfusion in vivo as a whole animal model of regional myocardial ischaemia, with left ventricular haemodynamic function measured by conductance catheter. Ischaemia-induced reductions in rate pressure product recovered faster in the FO2 group and post-ischaemic left ventricular pressure-volume loop integrity (shifted downwards and right in CON) was partially protected in both fish oil groups. Ischaemia-induced contractile dysfunction in rats is limited from fish oil doses equivalent to regular consumption of fish in the human diet. These observations highlight plausible and clinically relevant physiological changes that rationalise nutritional conditioning of the heart with DHA for on-going cardioprotection.

High DHA tuna oil alleviated cigarette smoking exposure induced lung inflammation via the regulation of gut microbiota and serum metabolites

Abstract In this study, the dose-dependent beneficial effects of tuna oil (TO) on cigarette smoke exposure induced lung inflammation were investigated. Treatments with low- (LD), moderate- (MD) and high-dosage (HD) of TO reduce the C-reactive protein concentration in serum, significantly down-regulated and up-regulated the mRNA levels of proinflammatory and anti-inflammatory cytokines in the lung, respectively. TO treatment inhibited the activation of the nuclear factor-kappaB (NF-κB) signaling pathway and the NLR family pyrin domain-containing 3 (NLRP3) inflammasome. In addition, TO treatments reduced the MDA concentration and enhanced the activities of SOD and GSH-Px in serum. What’s more, TO treatment modulated the gut microbiota by increasing the abundance of Lactobacillus species and short-chain fatty acid producers and decreasing the abundance of opportunistic pathogens, as well as affecting the amino acid metabolism in serum. This research clarified the anti-inflammatory mechanism of TO on cigarette smoking exposure induced lung inflammation in mice.

Extraction of fish oil from fish heads using ultra-high pressure pre-treatment prior to enzymatic hydrolysis

Extraction of fish oil from fish byproducts not only increases the utilization rate of fish resources but also reduces environmental pollution. Extraction methods affect the recovery and quality of fish oil. In this study, fish oil was extracted from yellowfin tuna (Thunnus albacares) heads using enzymatic hydrolysis extraction after single ultra-high pressure pre-treatment (EHSUP). The processing parameters of extraction were optimized with a two-factor repeated experimental design. The results showed that ultra-high pressure pre-treatment of the tuna heads prior to enzymatic hydrolysis was suitable for extracting fish oil and effectively increased the oil yield. The optimum parameters of ultra-high pressure pre-treatment were 200 MPa for 10 min or 100 MPa for 20 min, and the optimum parameters of enzymatic hydrolysis were 1% papain and 55 °C for 60 min. Considering the fatty acid profiles and the oxidation stability, yellowfin tuna oil is a high-quality, docosahexaenoic acid (DHA)-based product with high economic value. Industrial relevanceUltra-high pressure treatment is a novel food processing technology. In general, the main disadvantage of enzymatic hydrolysis extraction is its lower oil recovery than that of solvent extraction. This study investigated the application of ultra-high pressure on fish byproducts prior to enzymatic hydrolysis oil extraction. The results showed that the oil recovery improved by subjecting the tuna heads to ultra-high pressure pre-treatment prior to enzymatic hydrolysis extraction. These results will provide a technical reference for efficiently extracting high-quality fish oil.

Long-chain monounsaturated fatty acids improve endothelial function with altering microbial flora

Fish oil-derived long-chain monounsaturated fatty acids (LCMUFAs) with a carbon chain length longer than 18 units ameliorate cardiovascular risk in mice. In this study, we investigated whether LCMUFAs could improve endothelial functions in mice and humans. In a double-blind, randomized, placebo-controlled, parallel-group, multi-center study, healthy subjects were randomly assigned to either an LCMUFA oil (saury oil) or a control oil (olive and tuna oils) group. Sixty subjects were enrolled and administrated each oil for 4 weeks. For the animal study, ApoE-/- mice were fed a Western diet supplemented with 3% of either gadoleic acid (C20:1) or cetoleic acid (C22:1) for 12 weeks. Participants from the LCMUFA group showed improvements in endothelial function and a lower trimethylamine-N-oxide level, which is a predictor of coronary artery disease. C20:1 and C22:1 oils significantly improved atherosclerotic lesions and plasma levels of several inflammatory cytokines, including IL-6 and TNF-α. These beneficial effects were consistent with an improvement in the gut microbiota environment, as evident from the decreased ratio of Firmicutes and/ or Bacteroidetes, increase in the abundance of Akkermansia, and upregulation of short-chain fatty acid (SCFA)-induced glucagon-like peptide-1 (GLP-1) expression and serum GLP-1 level. These data suggest that LCMUFAs alter the microbiota environment that stimulate the production of SCFAs, resulting in the induction of GLP-1 secretion. Fish oil-derived long-chain monounsaturated fatty acids might thus help to protect against cardiovascular disease.

Gelatin Films from Carp Skin Crosslinked by Gallic Acid and Incorporated with Chitosan/Tuna Lipid Fractions

Gelatin was extracted from carp skin and reticulated with gallic acid; afterward, gelatin samples were crosslinked with addition of chitosan produced from shrimp waste and, bleached oil and free fatty acids (FFA) extracted from tuna heads. Carp gelatin showed good yield (20.4%), hydroxyproline content of 13.8% and high gel strength (245 g). Chitosan presented 85%DD and MW of 159 kDa, and the tuna oil had 68.2% of unsaturated fatty acids, being around 29% of EPA and DHA. Films showed thickness, color, and transparencies characteristic of fish gelatins. Films crosslinked with gallic acid, incorporated with chitosan and the tuna lipid fractions showed better mechanical and permeation properties that the other films. FT-IR analysis showed that crosslinking let to an amides II and III decrease, a typical attribute in films with low water vapor permeability. All films presented higher melting temperatures than the pure gelatin film, indicating less thermal degradation and better quality. The results expressed that the incorporations of chitosan, bleached oil and FFA improved the properties of crosslinked gelatin films from carp skin. As all materials used in work are byproducts from fishery industry, this fact could collaborate to reduce the environmental impacts caused by their inadequate discards in nature.

Taking the bait: The influence of attractants and microhabitat on detections of fauna by remote‐sensing cameras

SummaryAutonomously triggered cameras are a common wildlife survey technique. The use of attractants and surrounding microhabitats is likely to influence detection probabilities and survey outcomes; however, few studies consider these factors. We compared three attractants (peanut butter‐based, tuna‐based and a control) in a Latin square design through a coastal shrubland with high microhabitat variability at Cape Otway, Victoria, Australia (38º50ʹS, 143º30ʹE). Deployments involved 36 cameras for four days in each of five years. The percentage cover of each vegetation structural type (low [no or sparse cover], moderate [grass] or high [shrubs]) within 20 m of each camera was calculated and reduced to a single variable using PCA. Dynamic occupancy modelling, with lure type and vegetation structure as covariates of detection probability, found that peanut butter attracted the greatest diversity of species (24 of 35 species, 69%) and yielded the greatest number of detections (50% of 319) when compared with tuna oil (66% and 24%, respectively) and the control (43% and 26%, respectively). Peanut butter attracted more Macropodidae (wallabies) and Muridae (rats and mice); however, vegetation structural variables were the greatest influence on Corvidae/Artamidae (raven/currawong) detections with higher detectability in more open areas. Vegetation structure also influenced Muridae detections. This study reinforces the critical choice of appropriate attractants and camera placement when investigating vertebrate groups and highlights the role of microhabitat in the detection of small mammals and birds. We suggest future large‐scale camera surveys consider different bait types and microhabitats in their designs, to control for any biases and enable future advice on ‘optimal’ methods.

Gut microbiota mediated the protective effects of tuna oil on collagen-induced arthritis in mice.

Rheumatoid arthritis is emerging as a chronic autoimmune disease worldwide. In this study, the beneficial effects of tuna oil (TO) on collagen-induced arthritis (CIA) mice were investigated. Dietary administration of TO relieved arthritis severity and joint bone erosion, and ameliorated systemic inflammation. Furthermore, TO treatments regulated the phosphorylation of nuclear factor-kappa B (NF-κB) and Wnt1/β-catenin signaling pathways in the joint, enhanced osteoblastogenesis biomarkers and suppressed osteoclastogenesis biomarkers, and subsequently re-balanced bone remodeling. Moreover, the impaired intestinal epithelial barrier was repaired after TO treatments, along with gut microbiota modulation. By employing fecal microbiota transplantation, we clarified that the beneficial effects of TO in CIA alleviation were mediated by the modulated gut microbiota. These results indicated that gut microbiota mediated the protective effects of tuna oil on collagen-induced arthritis in mice.

Structured lipids of swine lard and oils from byproducts of skipjack tuna and of common carp

The aim was to obtain structured lipids by chemical interesterification of saturated fat (lard) with bleached oils from fish heads (carp and tuna). All materials were characterized by physicochemical analyses, gas chromatography for fatty acid profiles, nuclear magnetic resonance for unsaturated fatty acids esterified in sn-1,3 and sn-2 positions of the triacylglycerols, and differential scanning calorimetry for solid fat content (SFC). The amounts of eicosapentaenoic acid and docosahexaenoic acid were much higher for tuna oil (32%), showing the presence of docosahexaenoic acid in the structured lipids. The higher modifications of lard were with 1% of catalyst and 70:30 ratio of lard : fish oil. Through the SFC analysis, information about the structured lipids’ characteristics were obtained, making it possible to define the most suitable technological applications. After the reaction, SFC reduced from 2% to 30% when compared to the swine lard, and the highest changes had occurred when tuna oil was used. Practical applications In recent years, the growing demand for foods with nutritional properties has aroused the interest about the development of a new generation of lipids, the so-called healthy lipids. This work presents as a differential, the effect evaluation of the fish oils from different cultures (pisciculture and mariculture) in the characteristics of structured lipids, which are obtained by chemical interesterification reaction of these oils with swine lard. The presence of different types of fatty acids in the same triacylglycerol molecule can produce a compound with unique nutritional and metabolic properties. Thus, the use of fish oils with different fatty acid profiles can have a direct effect on the technological applications of the structured lipids. In addition, the incorporation of fatty acids as EPA and DHA, which are not naturally found in fats, besides conferring interesting technological characteristics, increases the nutritional value of the fat.

Enzymatic enrichment of n-3 polyunsaturated fatty acid glycerides by selective hydrolysis

Most natural oils are low in n-3 polyunsaturated fatty acids (n-3 PUFAs) content, which limits their application in health products. In this study, n-3 PUFAs in glyceride form were selectively enriched by lipase-mediated hydrolysis of n-3 PUFA-containing oils. First, commercial lipases were screened, and the lipase AY “Amano” 400SD from Candida cylindracea was the best choice in producing n-3 PUFA glycerides from tuna oil. Subsequently, the hydrolysis conditions were optimized. Under the optimal conditions, the highest n-3 PUFA content in the glyceride fraction was found to be 57.7% after enzymatic hydrolysis. Addition of Ca2+ to the system significantly shortened the reaction time from 10 to 4 h. When algal oil was used as substrate, total PUFA contents in the glyceride fraction were 89.9%. This study provides an efficient enzymatic process to produce n-3 PUFA-enriched glyceride concentrates and demonstrates that AY “Amano” 400SD can effectively discriminate against n-3 PUFAs during hydrolysis.

Biodiesel characteristics of tuna fish bio-oil waste in the transesterification process with variation of reaction time and stirring speed

Waste from fishery production from canned fish production in Indonesia is very abundant, this waste can be used as raw material for making biodiesel. In this research, the production of biodiesel from tuna oil waste is carried out through the transesterification process. The purpose of this study was to determine levels of Free Fatty Acid, the effect of reaction time and stirring speed on the transesterification process on the characteristics of biodiesel. Fixed variables used consisted of methanol plus bio-oil in a ratio (6: 1), methanol at a concentration of 98%, reaction temperature of 60 °C, KOH catalyst weighing 3.5 grams, while the independent variable consisted of the time of transesterification reaction and stirring speed. The variation of transesterification reaction time used is 1, 2, and 3 hours while the variation of the speed of stirring the transesterification reaction is 160, 245, and 360 rpm. The optimal conditions obtained were 2 hours reaction time and 360 rpm stirring speed with biodiesel characteristics, namely a density of 849 kg / m ^ 3, viscosity of 3.53 cSt, water content of 0.6%, calorific value of 9,390 cal / gr, flash point 84 ° C, and acid number 3.6343 mg KOH / gr.

Cardiac Arrhythmia Prevention in Ischemia and Reperfusion by Low-Dose Dietary Fish Oil Supplementation in Rats

Supplementing animal diets with fish oil increases myocardial omega-3 polyunsaturated fatty acids [ω-3 (n-3) PUFA], lowers heart rate, and prevents malignant cardiac arrhythmias. In contrast to epidemiological reports, results of some human clinical trials and of unphysiologically high doses employed in animal studies call into question the application of dietary ω-3 PUFA for cardioprotection. This study tested the hypothesis that low ω-3 PUFA dietary thresholds for myocardial incorporation in rats, equivalent in dose to what humans derive from eating fish, can reduce heart rate and arrhythmia vulnerability. Male Sprague-Dawley rats (12-15 wk old) were fed isoenergetic diets containing 10% fat for 4-5 wk. The control diet (CON) contained 5.5% beef tallow, 2.5% sunflower seed oil, and 2% olive oil. Fish oil diets contained high-DHA tuna oil, exchanged for olive oil: 0.31% [fish oil group 1 (FO1)] (human equivalent EPA+DHA 570 mg/d); 1.25% [fish oil group 2 (FO2)] (equivalent EPA+DHA 2.3 g/d). Anaesthetized rats (pentobarbital, 60 mg/kg intraperitoneally) were subjected in vivo to 15-min cardiac ischemia by left coronary artery occlusion and then reperfusion, with arrhythmias detected by electrocardiogram. Fish oil dose dependently modulated myocardial membrane fatty acids (DHA mean±SEM: CON, 5.0±0.2%; FO1, 13.1±0.9%; FO2, 18.3±0.4%; n=4-5; P-trend<0.001 ANOVA); resting heart rate (CON, 453±6; FO1, 432±4; FO2, 422±5 bpm; n=15-18; P-trend<0.001); reduced ventricular fibrillation (VF) (CON, 89%; FO1, 60%; P=0.052; FO2, 50%; n=15-18; P=0.013 chi square); and total arrhythmia severity (arrhythmia score: CON, 6.1±0.4; FO1, 4.6±0.5; FO2, 3.1±0.7; n=15-18; P-trend<0.01) during ischemia and reperfusion (VF: Con, 86%; FO1, 22% P=0.011; FO2, 8% P=0.001; n=7-12); (arrhythmia score: CON, 4.6±0.3; FO1, 3.1±0.3; FO2, 1.3±0.3; n=7-12; P-trend<0.001). Ventricular arrhythmias were prevented and heart rate was slowed by lower ω-3 PUFA intake in rats than previously reported, equivalent to human fish consumption and associated with increased myocardial DHA. The efficacy of low-dose fish oil demonstrates biological plausibility for nutritional ω-3 fatty acid-mediated cardioprotection and suggests that effectiveness in human clinical trials may be obscured by failure to exclude fish eaters.

Novel high-docosahexaenoic-acid tuna oil supplementation modulates gut microbiota and alleviates obesity in high-fat diet mice.

Studies have documented the benefits of fish oil in different diseases because of its high n‐3 polyunsaturated fatty acid content. However, these studies mostly used commercially available fish oil supplements with a ratio of 18/12 for eicosapentaenoic acid and docosahexaenoic acid (DHA). However, increasing DHA content for this commonly used ratio might bring out a varied metabolic effect, which have remained unclear. Thus, in this study, a novel tuna oil (TO) was applied to investigate the effect of high‐DHA content on the alteration of the gut microbiota and obesity in high‐fat diet mice. The results suggest that high‐DHA TO (HDTO) supplementation notably ameliorates obesity and related lipid parameters and restores the expression of lipid metabolism‐related genes. The benefits of TOs were derived from their modification of the gut microbiota composition and structure in mice. A high‐fat diet triggered an increased Firmicutes/Bacteroidetes ratio that was remarkably restored by TOs. The number of obesity‐promoting bacteria—Desulfovibrio, Paraeggerthella, Terrisporobacter, Millionella, Lachnoclostridium, Anaerobacterium, and Ruminiclostridium—was dramatically reduced. Desulfovibrio desulfuricans, Alistipes putredinis, and Millionella massiliensis, three dysbiosis‐related species, were especially regulated by HDTO. Regarding the prevention of obesity, HDTO outperforms the normal TO. Intriguingly, HDTO feeding to HFD‐fed mice might alter the arginine and proline metabolism of intestinal microbiota.

Effects of dietary oils prepared from the internal organs of the Japanese giant scallop (Patinopecten yessoensis) on cholesterol metabolism in obese type-II diabetic KK-Ay mice.

Our research team has successfully prepared high‐quality scallop oil (SCO), containing high eicosapentaenoic acid (EPA) and phospholipids (PL) from the internal organs of Japanese giant scallop (Patinopecten yessoensis) which is the largest unutilized marine resource in Japan. In this study, we prepared SCOs from scallop internal organs obtained from Mutsu (Aomori) and Uchiura (Hokkaido) bays in Japan, and named them SCO‐M and SCO‐U, respectively. This study aimed to investigate the effects of dietary SCO‐M and SCO‐U on cholesterol metabolism in obese type‐II diabetic KK‐Ay mice. Four‐week‐old male KK‐Ay mice were divided into four groups. The Control group was fed with AIN93G‐modified high‐fat (3 wt% soybean oil + 17 wt% lard) diet, and the other groups were fed with high‐fat diet, in which 7 wt% of the lard contained in the Control diet was replaced with SCO‐M, SCO‐U, or tuna oil (TO). After the mice had been fed with the experimental diet for 49 days, their serum, liver, and fecal lipid contents, as well as their liver messenger ribonucleic acid expression levels, were evaluated. The SCO‐M and SCO‐U groups were significantly decreased liver cholesterol contents compared to those of the Control and TO groups, partially through the enhancement of the fecal neutral sterol excretions and the tendency to increase the cholesterol 7α‐hydroxylase expression level of the liver. These results indicated that dietary SCO‐M and SCO‐U exhibited cholesterol‐lowering functions in the liver that can help prevent the development of lifestyle‐related diseases.

Lipase-catalysed synthesis of mono- and di-acyl esters of glyceryl caffeate in propylene carbonate and their antioxidant properties in tuna oil

Development of new non-toxic antioxidants with diverse hydrophobic properties is important due to growing concerns about the toxicity of artificial oil-soluble antioxidants, the comparatively low effectiveness of natural options, and the complex role hydrophobicity plays in antioxidant effectiveness. Using caffeic acid, a naturally occurring phenolic acid with potent antioxidant activity, a range of glyceryl caffeate esters (decanoate and palmitate) were prepared using lipase-catalysed esterification reactions. Glyceryl-1-caffeate (GC) was prepared from ethyl caffeate and glycerol (acting as both the solvent and the substrate), catalysed by immobilised Candida Antarctica lipase B (Novozym-435) at 80 °C under vacuum. Esterification of GC with decanoic acid using immobilised Thermomyces lanuginosus lipase (TLIM) or Novozym-435 was found to be selective towards mono-acylated or di-acylated products, respectively. The reaction was performed in an unconventional solvent, propylene carbonate (PC), which has many of the attributes of a green solvent. Product conversions in PC were comparable to the best performing conventional solvents. In contrast to conventional volatile solvents, the low volatility of PC allowed the reaction to be performed under vacuum, without the need for molecular sieves for removal of water produced during the reaction. Diisopropyl ether was effective at extracting the more lipophilic products from PC. Both the lipase (Novozym-435) and PC were reused four times with only a small loss in conversion efficiency. Glyceryl caffeate esters performed much better than α-tocopherol at protecting bulk tuna oil from oxidation (analysed using Rancimat). A comparison of glyceryl caffeate esters (decanoate/palmitate and mono-/di-acylated) showed that their antioxidant effectiveness in bulk tuna oil was not affected by chain-length, but compounds containing only one fatty ester were slightly more effective than those containing two fatty esters.

Polychlorinated Biphenyls in Food.

We measured the concentrations of 205 polychlorinated biphenyl (PCB) congeners in 26 food items: beef steak, butter, canned tuna, catfish, cheese, eggs, french fries, fried chicken, ground beef, ground pork, hamburger, hot dog, ice cream, liver, luncheon meat, margarine, meat-free dinner, milk, pizza, poultry, salmon, sausage, shrimp, sliced ham, tilapia, and vegetable oil. Using Diet History Questionnaire II, we calculated the PCB dietary exposure in mothers and children participating in the AESOP Study in East Chicago, Indiana, and Columbus Junction, Iowa. Salmon had the highest concentration followed by canned tuna, but fish is a minor contributor to exposure. Other animal proteins are more important sources of PCB dietary exposure in this study population. Despite the inclusion of few congeners and food types in previous studies, we found evidence of a decline in PCB concentrations over the last 20 years. We also found strong associations of PCB congener distributions with Aroclors in most foods and found manufacturing byproduct PCBs, including PCB11, in tilapia and catfish. The reduction in PCB levels in food indicates that dietary exposure is comparable to PCB inhalation exposures reported for the same study population.

Simple Wet Rendering Method for Extraction of Prime Quality Oil from Skipjack Tuna Eyeballs

AbstractOil from skipjack tuna (ST) eyeballs is extracted by the wet rendering method at 121 °C for different holding times (5–60 min) using an autoclave. Yield increases as heating time increases up to 20 min (p &lt; 0.05); no further increase is obtained with a longer heating time (p &gt; 0.05). Conversely, acid value and total polar compounds increase. However, peroxide value (PV), thiobarbituric acid reactive substances, and anisidine value (AnV) decrease up to 30 min. No changes in unsaponifiable matter (UM) or conjugated diene (CD) are attained, regardless of heating time. Polar components (PC) increase with heating time (p &lt; 0.05). All oil samples have a high polyunsaturated fatty acids (PUFA) content (40.46–41.00%), with monounsaturated fatty acids (MUFA) and saturated fatty acids (SFA) in the range of 20.94–21.26% and 37.77–38.45%, respectively. PUFA content is reduced slightly with a heating time of 60 min. Docosahexaenoic acid (DHA) (C22:6, n3) is the dominant fatty acid in all samples (31.67–32.24%). Based on FTIR spectra, heating for longer time results in lower intensity at wavenumbers of 3015 and 1740 cm−1. Thus, light yellow oil from ST eyeballs prepared by a green process for an appropriate time can serve as an excellent source of DHA and other PUFA.Practical Applications: Tuna oil is known to be a rich source of DHA and PUFA with health benefits. However, precooked tuna heads, generally used as raw material, yield oils with a very dark color and offensive odor, which require several refinery processes. To reduce the number of steps in the refinery process, tuna eyeballs which are separated from tuna heads can render higher quality fish oil. Moreover, the wet rendering process, a green process without toxic substances, can be used without causing environmental problems.

Broccoli byproducts for protection and co-delivery of EGCG and tuna oil

Neat epigallocatechin gallate (EGCG) has low bioavailability and tuna oil (TO) is prone to oxidation. Broccoli byproducts (BBP) were used for preparing TO-BBP (25% oil, dry basis) and TO-EGCG-BBP (20% oil and 20% EGCG, dry basis) powders. The gross composition and surface fat of powders and morphology of reconstituted emulsions were characterized. Oxipres® data (80 °C, 5 bar oxygen pressure) showed that the TO-EGCG-BBP formulation was more oxidatively stable [Induction period (IP) > 100 h] than TO-BBP (IP ~ 20 h). During in vitro digestion, 90% of EGCG was recovered in the whole intestinal digesta of the TO-EGCG-BBP formulation compared to 76% for the EGCG-BBP formulation and 66% for the neat EGCG. The use of BBP for co-delivering EGCG and TO increases oxidative stability of TO and improves EGCG stability during in vitro digestion. This study highlights the potential for formulating functional ingredient with BBP and contribute to food waste reduction.

Mitigation of lipid oxidation in tuna oil using gelatin pouches derived from horse mackerel (Trachurus japonicus) scales and incorporating phenolic compounds

Mitigative effects of phenolic compounds on lipid oxidation of tuna oil in gelatin film pouches from horse mackerel (Trachurus japonicus) scales were investigated during storage at 40 °C for 30 days under dark conditions. Improvements in the antioxidant activity of gelatin films were observed following the addition of phenolic compounds. Increases in peroxide values (PV) and 2-thiobarbituric acid reactive substance (TBARS) levels of tuna oil were significantly mitigated using gelatin pouches with ferulic acid, which had the fewest phenolic hydroxyl groups among the phenolic compounds tested. The ferulic-gelatin film also exhibited the highest DPPH radical-scavenging activity among the tested samples. These results indicate that the oxidation of lipids in tuna oil can be mitigated using gelatin films containing phenolic compounds, but its antioxidant activity is not directly related to the number of phenolic hydroxyl groups. Protein crosslinking in gelatin film is likely to be induced by aldehydes such as malondialdehyde (MDA), which is a final product of lipid oxidation, and this was observed following storage of tuna oil. Thus, it is suggested that care should be taken when using TBARS levels to evaluate lipid oxidation of foods in fish gelatin film pouches, since aldehydes including MDA are consumed for protein crosslinking.

Highly concentrated very long-chain PUFA obtainment by Urea complexation methodology

The intake of n-3 very long chain PUFA (VLCPUFA) develops several positive physiological actions. Thus, such compounds are currently used as healthy supplements for animals and humans, in animal experimentation, and as standards for chromatographic use. The urea complexation methodology is an old technique for obtaining PUFA concentrates; however, improvements can still be implemented for improving results using this methodology. In this work, highly concentrated eicosapentaenoic acid (EPA, 20:5n-3), docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (ARA, 20:4n-6) have been successfully obtained using such procedure. For this, five oil sources were used: commercially available tuna oil, DHASCO®, ARASCO®, and MARINOL®, and the oil from the microalga Nannochloropsis. Overall, after optimizing the urea:fatty acid ratio, DHA-, EPA-, and ARA-concentrates were obtained at 98.0, 43.0 and 82.8% of total fatty acids. This work clearly shows the importance of the proper selection of the oil source to achieve highly-purity VLCPUFA concentrates by the urea complexation method.