Lipid profiles of oil from trout (Oncorhynchus mykiss) heads,spines and viscera: Trout by-products as a possible source of omega-3 lipids?

Lipid profiles of fish oil extracted from trout heads, spines and viscera using supercritical carbon dioxide and Randall extraction with hexane were measured. The amount of unsaturated fatty acids (as a percentage of total fatty acids) was within the range of 72.6–75.3% in all the substrates. A significant presence of the most important omega-3 fatty acids was detected. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content in oil from spines, heads and viscera resulted to be 8.7% and 7.3%, 7.9% and 6.3%, and 6.4% and 6.0%, respectively. A low (≈3%), but worth noting, presence of lipids with omega-1 polyunsaturated fatty chains was observed in all the oils. Finally, significant differences were noticed in the relative amounts of triacylglycerides (TAG), diacylglycerides (DAG) and free fatty acids (FFA). Whereas oil from heads and spines was essentially composed of TAG (≈98%), in viscera oil the molar distribution ratio became TAG:DAG:FFA = 87:8:5.     

Fatty acid compositions of fish oil extracted from different parts of Indian mackerel (Rastrelliger kanagurta) using various techniques of supercritical CO2 extraction

Fatty acid compositions of fish oil extracted from different parts of Indian mackerel (Rastrelliger kanagurta) using various techniques of supercritical carbon dioxide (SC-CO₂) at optimised conditions (35 MPa, 60 °C, 2 ml/min) were analysed and compared to the results of Soxhlet extraction. The amount of polyunsaturated fatty acids (PUFA) recovered (as a percentage of total extracted fatty acids) were within the ranges of 73.24–74.68% in the skin, 68.36–69.37% in the flesh, 56.20–57.3% in the viscera and 61.21–62.09% in the heads. The greatest amount of the ω-3 fatty acids, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), were found in fish skin followed by flesh, heads and viscera. The greatest amounts of EPA (9–12%) and DHA (10–14%) were obtained using the soaking and pressure swing techniques. The pressure swing and soaking techniques are the most effective techniques for extracting the ω-3 family of fatty acids from fish samples.     

Yield,nutritional quality,and thermal-oxidative stability of Brazil nut oil (Bertolletia excelsa H.B.K) obtained by supercritical extraction

Functional and nutritional quality of oils is the most important parameter in food-related areas of study. The applicability of these products depends directly on the cost-benefit analysis and extraction yield. The objective of this study was to evaluate the yield, nutritional quality, and thermaloxidative stability of the Brazil nut oil obtained by supercritical carbon dioxide extraction under different conditions of temperature and pressure. The results showed that the highest extraction yield was obtained at pressure of 300 bar and temperature of 60 °C. The quality and colorimetric evaluations revealed a material with strong tendency to yellow color. Its fatty acid profile showed predominance of unsaturated fatty acids (75%). It was thermally stable under progressive temperature increases up to 300 °C. The oxidative stability showed oxidation induction time around 14.85 h. The spectroscopic profile confirms the quality of the oil obtained without the presence of carbon compounds that could indicate oxidative degradation.     

Supercritical CO2 extraction of oil from Arctic charr side streams from filleting processing

Although Arctic charr side streams contain limited amounts of fish flesh, they are a rich fish oil source (46.3 ± 0.6%). The aim of the study was to investigate the potential for valorization of Arctic charr filleting side streams through the extraction of oil by supercritical CO₂ technology. The effect of temperature (40 °C and 80 °C) and pressure (20, 35 and 45 MPa) on the final extract after supercritical fluid extraction (SFE) was evaluated. Temperature increase enhanced the yield but decreased the antioxidant activity at 45 MPa, did not affect the yield and the antioxidant activity at 35 MPa, whereas yield was limited at 20 MPa and 80 °C. Extracts were rich in monounsaturated fatty acids (56.7–58.3%, especially oleic acid 37.2–38.0%), and polyunsaturated fatty acids (20.2–26.1%, especially DHA 7.3–11.4%). The presence of astaxanthin significantly preserved the extracts from oxidation.Industrial relevanceSupercritical carbon dioxide extraction is a green technology appropriate for the recovery of non-polar and heat sensitive compounds. The extracted Arctic charr oils were rich in polyunsaturated fatty acids and astaxanthin which inhibited oxidation in combination with the absence of oxygen and light during the process. This technology could be an excellent alternative for more sustainable valorization of fish processing side streams.     

提取黄鳍金枪鱼眼窝肉鱼油的方法比较研究

以黄鳍金枪鱼(Thunnus albacores眼窝肉为研究对象,采用隔水蒸煮法、酶解法、碱水解法和超临界CO2(SC-CO2)萃取法提取鱼油,对所得鱼油的理化性质和脂肪酸组成进行分析测定。结果表明:SC-CO2萃取法和酶解法提取率无显著性差异,但明显高于隔水蒸煮法和碱水解法;SC-CO2萃取法获得的鱼油达到我国水产行业SC/T3502—2000精制鱼油一级标准,其他3种方法达到SC/T3502—2000粗鱼油二级标准;SC-CO2萃取法提取的鱼油不饱和脂肪酸含量最高(74.29%),其中含EPA5.99%、DHA27.12%。因此,SC-CO2较其他3种方法提取金枪鱼眼窝肉中鱼油具有显著优势。     

Supercritical carbon dioxide extraction of the residual oil from palm kernel cake

Palm kernel cake contains residual oil that has never been retrieved and it is treated as wastes. In this study, supercritical carbon dioxide was used to separate the oil from the palm kernel matrix. The studied extraction parameters were at the set pressures 27.57, 34.47 and 41.36 MPa, temperatures 40-70 °C and carbon dioxide flow rate between 1 and 3 ml/min. The effect of the particle size on the oil yield was examined using different particle size that separated by sieving from ?106, ?150, ?180, ?250 and ?450 μm. The results showed that the highest oil removed was 9.26 g oil/100 g sample (p < 0.05) for the particle ?150 μm, and under extraction temperature of 70 °C, pressure 41.36 MPa, and carbon dioxide flow rate of 2 ml/min. The experimental results indicate that supercritical carbon dioxide extraction could be a viable technique to remove the remaining oil and to produce defatted palm kernel cake.     

Supercritical CO2 extraction optimization of pomegranate (Punica granatum L.) seed oil using response surface methodology

This study examined extraction of pomegranate seed oil by using supercritical carbon dioxide. Response surface methodology was used to evaluate the effects of the process parameters, namely extraction pressure, temperature and CO₂ flow rate on the yield of pomegranate seed oil. The extraction parameters were optimized with a central composite design experiment. The linear term of pressure, followed by the linear term of CO₂ flow rate, the quadratic terms of pressure, temperature and CO₂ flow rate and the interactions between pressure and temperature, as well as CO₂ flow rate and temperature, had significant effects on the oil yield (p < 0.05). Maximum yield of pomegranate seed oil from the mathematical model was predicted to be 156.3 g/kg dry basis under the condition of pressure 37.9 MPa and temperature 47.0 °C with CO₂ flow rate of 21.3 L/h. The fatty acid composition and the tocopherols' content of pomegranate seed oil extracted using supercritical CO₂ were compared with those obtained by Soxhlet method. Minor difference was found in the fatty acid composition of the oils extracted by the two methods. The content of total tocopherols was about 14% higher in the oil extracted with supercritical CO₂ than that obtained by Soxhlet extraction.     

超临界二氧化碳富集提纯鱼油中EPA和DHA的研究进展（Ⅰ）──超临界二氧化碳与鱼油脂肪酸的相平衡研究

鱼油中的特征脂肪酚ＥＰＡ（廿碳五烯酸）和ＤＨＡ（廿二碳六烯酸）对人体的医疗保健作用受到越来越广泛的重视。综述了近年来人们对超临界二氧化碳（ＳＣ－Ｃ０２）与鱼油脂肪酸相平衡的研究概况，分析了温度、压力、夹带剂等对ＳＣ－ＣＯ２从鱼油脂肪酸混合物中萃取提纯ＥＰＡ和ＤＨＡ的影响。     

Extraction of canola seed (Brassica napus) oil using compressed propane and supercritical carbon dioxide

This study aimed to investigate the extraction of canola seed (Brassica napus) oil using supercritical carbon dioxide and compressed propane as solvents. The extractions were performed in a laboratory scale unit at temperatures and pressures of 40, 50 and 60 °C and 20, 22.5 and 25 MPa for carbon dioxide and 30, 45 and 60 °C and 8, 10 and 12 MPa for propane extractions, respectively. The results indicated that pressure and temperature were important variables for the CO₂ extraction, while temperature is the most important variable for the extraction yield with propane. The extraction with propane was much faster than that with carbon dioxide. The characteristics of the extracted oil, that is, the oxidative stability determined by DSC and the chemical profile of fatty acids determined by gas chromatography, were similar for the two solvents. The overall extraction curves were well described by the Sovová model.     

Effects of dietary supplemental fish oil during the peripartum period on blood metabolites and hepatic fatty acid compositions and total triacylglycerol concentrations of multiparous Holstein cows

The objectives were to evaluate the effects of dietary fish oil on plasma metabolite, hepatic fatty acid composition, and total triacylglycerol concentrations. Multiparous Holstein cows (n = 42) were completely randomized to 1 of 3 treatments at 3 wk prepartum. Treatments were no supplemental lipid or supplemental lipid from either Energy Booster (Milk Specialties Co., Dundee, IL) or fish oil. Treatment diets were fed from −21 d relative to expected date of parturition until 10 d postpartum. Treatments were fed as a bolus before the a.m. feeding. The dose of lipid fed during the prepartum period was 250 g, whereas approximately 0.92% of the previous day's dry matter intake was supplemented postpartum. Blood was collected 3 times weekly for determination of plasma metabolites. Liver biopsies were performed at 21 and 10 d before expected date of parturition and 1 and 14 d after parturition to determine fatty acid compositions and total triacylglycerol concentrations. Dry matter intake, milk yield, and loss of body weight or body condition score were not affected by supplementing the diet with lipid or by the source of lipid. Supplemental lipid tended to increase plasma glucose and decrease nonesterified fatty acids during the postpartum period. Furthermore, plasma β-hydroxybutyrate was reduced during the postpartum period in the lipid-supplemented treatments. However, source of supplemental lipid had no influence on any blood metabolite. Supplemental fish oil altered the fatty acid composition of liver phospholipids and triacylglycerols, decreasing total saturated fatty acids and increasing total n-3 and long-chain polyunsaturated fatty acids (>20 carbon fatty acids). Despite the altered fatty acid composition, hepatic total triacylglycerol concentrations were unaffected by supplemental fish oil. Furthermore, the improved metabolic profile following lipid supplementation did not decrease hepatic total triacylglycerol concentrations.     

Quality enhancement in fresh and frozen lingcod (Ophiodon elongates) fillets by employment of fish oil incorporated chitosan coatings

The 3% chitosan solutions incorporating 10% fish oil (w/w chitosan, containing 91.2% EPA and DHA) with or without the addition of 0.8% vitamin E were prepared. Fresh lingcod (Ophiodon elongates) fillets were vacuum-impregnated in coating solution at 100 mm Hg for 10 min followed by atmospheric restoration for 15 min, dried, and then stored at 2 °C or −20 °C for 3-weeks and 3-months, respectively, for physicochemical and microbial quality evaluation. Chitosan–fish oil coating increased total lipid and omega-3 fatty acid contents of fish by about 3-fold, reduced TBARS values in both fresh and frozen samples, and also decreased drip loss of frozen samples by 14.1–27.6%. Chitosan coatings resulted in 0.37–1.19 and 0.27–1.55 log CFU/g reductions in total plate and psychrotrophic counts in cold stored and frozen stored samples, respectively. Chitosan–fish oil coatings may be used to extend shelf-life and fortify omega-3 fatty acid in lean fish.     

Feeding feedlot steers fish oil alters the fatty acid composition of adipose and muscle tissue

Sixteen steers (441±31.7kg initial body weight) consumed two high concentrate diets with either 0 or 3% fish oil to determine the impact of fish oil, an omega-3 fatty acid source, on the fatty acid composition of beef carcasses. Collected tissue samples included the Longissimus thoracis from the 6th to 7th rib section, ground 10th to 12th rib, liver, subcutaneous adipose tissue adjacent to the 12th rib, intramuscular adipose tissue in the 6th to 7th rib sections, perirenal adipose tissue, and brisket adipose tissue. Including fish oil in the diet increased most of the saturated fatty acids (P<0.01) and proportions of polyunsaturated fatty acids (P<0.06), and decreased (P<0.01) proportions of monounsaturated fatty acids. Dietary fish oil increased (P<0.01) levels of omega-3 fatty acids in sampled tissues, resulting in lower (P<0.01) omega-6:omega-3 ratios. The weight percentages of C20:5 and C22:6 in tissue may provide the recommended daily allowance for humans. Fish oil may have a role in beef niche marketing if there are no deleterious effects on consumer satisfaction.     

Effects of supercritical carbon dioxide extraction parameters on virgin coconut oil yield and medium-chain triglyceride content

The extraction of coconut oil has been performed using supercritical carbon dioxide (SC-CO₂). The extractions were performed at pressure and temperature ranges of 20.7–34.5 MPa and 40–80 °C, respectively. It was observed that almost all (more than 99%) of the total oil could be extracted. Response surface methodology (RSM) was applied to evaluate the effects of the parameters (pressure, temperature and CO₂ consumption) on the extraction yield and medium-chain triglycerides (MCTs), in terms of the fatty acid content in the extracted oil. A correlation was established with p-values for both responses significant at the 95% confidence level.     

Supercritical carbon dioxide extraction of polyunsaturated fatty acids from Northern shrimp (Pandalus borealis Kreyer) processing by-products

This study investigated the potential of Northern shrimp (Pandelus borealis Kreyer) by-products as a source of omega-3 polyunsaturated fatty acids (ω-3 PUFAs). The by-products (heads, shell and tail) of processing accounted for approximately 50–60% of the catch. Supercritical CO₂ extraction (SFE) of the by-products at 35 MPa and 40 °C generated a deep red oil, rich in ω-3 PUFAs, specifically 7.8 ± 0.06% eicosapentaenoic acid (EPA) and 8.0 ± 0.07 % docosahexaenoic acid (DHA).     

Salmon by-product storage and oil extraction

Oils extracted from wild salmon by-products are excellent sources of long chain omega-3 polyunsaturated fatty acids including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). However, quality loss is expected if time delays are encountered before oil extraction. The free fatty acid levels (FFA), fatty acid profile and total fat soluble antioxidant activity in extracted oil from aging pink salmon heads and viscera stored at two temperatures (6 and 15 °C) for four days were determined. The FFA values in raw salmon heads and viscera increased with storage time and temperature. A significant difference (p < 0.05) from the starting material was noted at day 1 at both temperatures for FFA. Fatty acid composition data indicated no changes in the levels of long-chain omega-3 fatty acids with the respective temperature. The concentration of long-chain omega-3 fatty acids EPA ranged from 9.3 to 11.3 g/100 g of crude oil and DHA ranged from 12.3 to 13.1 g/100 g of crude oil. The antioxidant activity of the pink salmon oils at day 0 was 0.89 ± 0.15 μmole Trolox equivalent/g of crude oil. Significant decreases (p < 0.05) from the starting material were noted on day 2 for 15 °C samples and day 3 for 6 °C samples. After four days of storage antioxidant levels (Trolox equivalent/g of crude oil) were approximately 25% of initial values. Oil extracted from raw salmon heads and viscera remained a good source of long chain omega-3 fatty acids even after 4 days of raw material storage at 15 °C; however, fat soluble antioxidant activity was reduced and free fatty acid levels increased with increased raw material storage temperature and time.     

Comparison of essential oil compositions of Salvia mirzayanii obtained by supercritical carbon dioxide extraction and hydrodistillation methods

Essential oil of Salvia mirzayanii cultivated in Iran was obtained by hydrodistillation and supercritical (carbon dioxide) extraction methods. The oil was analysed by capillary gas chromatography using flame ionization and mass spectrometric detections. The compounds were identified according to their retention indices and mass spectra (EI, 70 eV). The effects of different parameters such as pressure, temperature, modifier volume and extraction times (dynamic and static) on the supercritical fluid extraction (SFE) of S. mirzayanii oil were investigated. The results showed that, under a pressure of 35.5 MPa, temperature of 35 °C, 6% methanol, dynamic extraction time of 50 min and static extraction time of 30 min, extraction was more selective for the linalyl acetate. Thirty four compounds were identified in the hydrodistilled oil. The major components of S. mirzayanii were linalyl acetate (7.6%), 1,8-cineole (8.0%), linalool (9.0%) and 8-acetoxy linalool (11.0%). However, by using supercritical carbon dioxide in optimum conditions, only three components contain more than 63% of the oil. The yield of the obtained oil based on hydrodistillation was 2.20% (v/w). Extraction yield based on the SFE varied in the range of 1.50–9.67% (w/w) under different conditions. The results revealed that, in Iranian S. mirzayanii oil, linalyl acetate is a major component.     

GC-TOF-MS定性和定量评估5 种木本油料种籽油的脂肪酸

采用气相色谱-飞行时间串联质谱和超临界二氧化碳提取技术,分析评价5 种木本油料种籽油的脂肪酸组成及相对含量。油茶和榛子种籽油中富含油酸,亚油酸是沙棘和文冠果种籽油中的主要脂肪酸,牡丹种籽油中的亚麻酸含量最高。沙棘种籽油的单不饱和脂肪酸与饱和脂肪酸比值为1.57：1,亚油酸与亚麻酸的比值为1.56：1,符合功能性健康食用油的标准;牡丹种籽油是补充人体ω-3脂肪酸的优质食用油;油茶和榛子种籽富含单不饱和脂肪酸,适合食品加工;文冠果种籽油含有3 种长链单不饱和脂肪酸（如神经酸等）。本实验评价了5 种木本油料油脂脂肪酸的组分,对指导企业生产生物活性油和人们的健康消费具有重要意义。     

Milk production and composition from cows fed small amounts of fish oil with extruded soybeans

Eight Holstein (189 ± 57 DIM) and 4 Brown Swiss (126 ± 49 DIM) multiparous cows were used in a replicated 4 × 4 Latin square with 28-d periods to determine the minimal dietary concentration of fish oil necessary to maximize milk conjugated linoleic acid (CLA) and vaccenic acid (VA). Treatments consisted of a control diet with a 50:50 ratio of forage to concentrate (dry matter basis), and 3 diets with 2% added fat consisting of 0.33% fish oil, 0.67% fish oil, and 1% fish oil with extruded soybeans providing the balance of added fat. Dry matter intake (23.1, 22.6, 22.8, and 22.9 kg/d, for control, low, medium, and high fish oil diets, respectively) was similar for all diets. Milk production (21.5, 23.7, 22.7, and 24.2 kg/d) was higher for cows fed the fat-supplemented diets vs. the control. Milk fat (4.42, 3.81, 3.80, and 4.03%) and true protein (3.71, 3.58, 3.54, and 3.55%) concentrations decreased when cows were fed diets containing supplemental fat. Concentration of milk cis-9,trans-11 CLA (0.55, 1.17, 1.03, and 1.19 g/100 g of fatty acids) was increased similarly by all diets containing supplemental fat. Milk VA (1.12, 2.47, 2.13, and 2.63 g/100 g of fatty acids) was increased most in milk from cows fed the low and high fish oil diets. Milk total n-3 fatty acids were increased (0.82, 0.96, 0.92, and 1.01 g/100 g of fatty acids) by all fat-supplemented diets. The low fish oil diet was as effective at increasing VA and CLA in milk as the high fish oil diet, showing that only low concentrations of dietary fish oil are necessary for increasing concentrations of VA and CLA in milk.     

Supercritical carbon dioxide extraction of seed oil from Opuntia dillenii Haw. and its antioxidant activity

Supercritical carbon dioxide extraction of seed oil from Opuntia dillenii Haw. and its antioxidant activity were investigated in this study. The effects of main operating parameters including extraction pressure, temperature, time and CO₂ flow rate on the extraction yield of seed oil were studied. The maximum extraction yield of 6.65% was achieved at a pressure of 46.96 MPa, a temperature of 46.51 °C, a time of 2.79 h and a CO₂ flow rate of 10 kg/h. The chemical composition of the seed oil was analysed by GC–MS. The main fatty acids were linolenic acid (66.56%), palmitic acid (19.78%), stearic acid (9.01%) and linoleic acid (2.65%). The antioxidant activity of seed oil was assessed by means of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay and β-carotene bleaching test. Both methods demonstrated notable antioxidant activity of seed oil, which is nearly comparable to the references ascorbic acid and butylated hydroxytoluene (BHT). The antioxidant activity of the seed oil was also found to be concentration-dependent.     

Enrichment of food products with polyunsaturated fatty acids by fish oil addition

Fish oil remains the main dietary source of long chain polyunsaturated fatty acids omega-3, which desirably impact on human health. Increase of omega-3 fatty acids intake is currently recommended. Results of many studies showed that consumption of food products enriched with fish oil offers the potential health benefits, especially in protection against cardiovascular diseases (CVD), cancer and improvement of brain development and function. Health influence, methods, advantages and disadvantages of food enrichment with fish oil as well as characteristics of market of such products were presented.