High Content Of Polyunsaturated Fatty Acids Research Articles

Comparision of Green and Conventional Extraction Methods on Lipid Yield and Fatty Acid Profiles of Fish Species

The efficiency of the green extraction methods ultrasound‐assisted extraction (UAE) and microwave‐assisted extraction (MAE), and conventional methods (Soxhlet and Bligh and Dyer), on lipid content and fatty acid profiles of six fish species (Mullus barbatus, red mullet; Upeneus moluccensis, goldband goatfish; Mullus surmuletus, surmullet; Anguilla anguilla, European eel; Pagellus erythrinus, common pandora, and Saurida undosquamis, brushtooth lizardfish) are evaluated. The results of lipid content of fish species show that the Bligh and Dyer method and UAE in general are more efficient than other methods. There are statistical differences in the fatty acid composition of fish oil by four extraction methods (p < 0.05). Saturated (SFA), monounsaturated (MUFA), and polyunsaturated fatty acid (PUFA) contents of fish species range from 29.51 mg 100 g−1 fish (Soxhlet)–1400 mg 100 g−1 (UAE), 15.52 mg 100 g−1 (UAE)–2237.18 mg 100 g−1 (Bligh and Dyer), and 14.36% (Soxhlet)–646 mg 100 g−1 (Bligh and Dyer), respectively. Generally, Bligh and Dyer give the higher values in surmullet, red mullett, and common pandora in terms of SFA, MUFA, PUFA, and the dominant fatty acids (C16:0, C18:0, C16:1, C18:1n9, C18:1n7, C22:1n9, EPA, DHA), whereas MAE and UAE methods give better results in goldband goldfish and European eel, respectively. Thus, extraction methods affect the lipid yield and fatty acid profiles of extracted oil of different fish species.Practical Application: Total lipid content of seafood is an important parameter used in biochemical, physiological, and nutritional studies. Thus, reliable methods for the quantitative extraction of lipids from this type of food are of critical importance. The effects of green and conventional extraction methods on lipid yield and fatty acid profiles of fish species are compared in order to determine the most effective method for extracting lipid with high yield and high content of PUFA, especially EPA and DHA.The effects of green and conventional extraction methods on lipid yield and fatty acid profiles of fish species are evaluated. The extraction methods affect the lipid yield and fatty acid profiles of extracted oil of fish species. The Bligh and Dyer method and UAE in general are more efficient than other methods. In terms of SFA, MUFA, PUFA, EPA, and DHA; Bligh and Dyer gave the higher values in surmullet, redmullet, and common pandora whereas MAE and UAE methods gave better results in goldband goldfish and European eel, respectively.

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.

Efficient Extraction of a Docosahexaenoic Acid (DHA)-Rich Lipid Fraction from Thraustochytrium sp. Using Ionic Liquids.

Polyunsaturated fatty acids (PUFAs) play a significant role in the modulation and prevention of various diseases, and hence are attracting increasing attention from the biotech industry. Thraustochytrids are marine heterokonts that exhibit robust growth rates, high PUFA content, and more specifically, a large percentage of omega-3 fatty acids like docosahexaenoic acid (DHA). Recently, ionic liquids (ILs) have been shown to improve the efficiency of organic solvent extraction of oils from wet oleaginous yeast and microalgae under mild conditions. Two ILs, the imidazolium 1-ethyl-3-methylimidazolium ethylsulfate [C2mim][EtSO4] IL and the phosphonium (tetrabutylphosphonium propanoate [P4444][Prop]) IL were assessed for their ability to facilitate extraction of PUFA-containing lipids from a Thraustochytrium sp. (T18) through efficient cell wall disruption. The oil extracted after IL pretreatment was further characterized with respect to fatty acid methyl ester (FAME) composition, while the effects of process parameters, such as the ratio of ionic liquid to co-solvent, the mass ratio of microalgae to the mixture of ionic liquid, and type of co-solvent were also investigated for both ILs. The results indicate that these ILs can disrupt the cells of Thraustochytrium sp. when mixed with a co-solvent (methanol), and facilitated the recovery of oils over a large degree of dewatered Thraustochytrium biomass (0–77.2 wt% water) in a short period of time (60 min) at ambient temperature, hence demonstrating a water compatible, low-energy, lipid recovery method. The lipid recovery was not affected by repeated usage of recycled ILs (tested up to five times).

Repeatedly heated cooking oils induced alterations in erythrocyte membrane integrity and antioxidant status in cholesterol fed Sprague Dawley rats

Repeatedly heated cooking oils induce oxidative stress in animals. Erythrocytes are prone to free radical induced lipid peroxidation. This study compared the effects of repeatedly heated cooking oils on erythrocyte membrane changes in hypercholesterolemic rats. Coconut oil, mustard oil, and sunflower oil were heated at 210 ± 10°C for 15 hr. Fresh/heated oils (15%) and cholesterol (1%) were fed with experimental diet for 60 days. Chemical analysis showed deteriorative changes in heated oils, effect being lower in heated coconut oil. Elevated MDA and protein carbonyl content and compromised antioxidant status was observed in heated oil fed animals. Membrane bound enzymes were decreased and markers of in vivo hemolysis were significantly elevated in heated oil fed animals. Osmotic fragility of erythrocytes was also higher in heated oils fed groups. Our study shows increased lipid peroxidation associated with reduced antioxidant status of erythrocytes, make them more susceptible to hemolysis. Practical applications High fat and cholesterol are increasingly being included in the modern diet. Hypercholesterolemia and lipid oxidation are serious risk factors contributing to the pathogenesis of atherosclerosis. Thermally treated dietary fats in typical modern diets contain lipid peroxidation products. Cooking oils are repeatedly heated at high temperatures and reused for maximum profit during various food preparations. The nature of fatty acids influences the rate of lipid peroxidation occurring in oils during thermal treatments. The present study clearly showed that frying oils such as mustard oil and sunflower oil have lower stability than coconut oil because of high polyunsaturated fatty acid content. Results obtained from these investigations indicate that consumption of thermally oxidized cooking oil causes oxidative damage thereby increasing the risk of atherosclerosis. Hence for optimal use, it is necessary to distinguish the quality of oil and not to expose cooking oils to high temperatures for longer duration.

Digestibility and pricing of Chlorella sorokiniana meal for use in tilapia feeds

Several microalgae contain in excess of 50 % crude protein with amino acid profile comparable to that of fish meal. In addition, high polyunsaturated fatty acid contents encourage their use in animal feeding and nutrition, particularly in the formulation and processing of aquafeeds. This study aims at estimating the feasibility of Chlorella meal as feed ingredient for the feeding and nutrition of farmed tilapia based upon digestibility data. Juvenile tilapia were stocked in conical-bottomed tanks (200 L) with superficial, continuous water flow, and fed to apparent satiation in three daily meals with a reference diet and a test diet containing 30 % lyophilized Chlorella sorokiniana added of an inert marker. Feces were collected overnight by sedimentation in refrigerated, plastic containers coupled to the tanks and analyzed for determination of chemical composition and inert marker contents to estimate apparent digestibility coefficients (ADCs) of protein and energy of Chlorella meal; registered ADCs of Chlorella meal were 90.5 and 84.22, respectively. A pricing model considering the quantity of digestible nutrient was proposed based on ADCs of Chlorella and compared with the price of fishmeal (FM) and soybean meal (SBM). The indicative prices to elicit the use of Chlorella as a protein source rather than FM or SBM for the feed and nutrition of tilapia were 2.65 USD kg−1 and 0.66 USD kg−1, respectively.

Fatty acid composition of goose meat depending on genotype and sex.

ObjectiveThe aim of this study was to compare male and female geese of two contrasting genotypes in terms of fatty acid composition, indexes related to human health, lipid metabolism and oxidative stability of the meat.MethodsThe experiment was carried out on total of 120 geese of two different genotypes; the native breed Czech goose (CG) and commercial hybrid Novohradska goose (NG). One-d-old goslings were divided into 4 groups according to genotype and sex, and 8 birds from each group were slaughtered at 8 weeks of age.ResultsThe effects of the interactions between genotype and sex were observed on growth performance and carcass traits. Final body weight (p<0.001), daily weight gain (p<0.001), daily feed intake (p<0.001), slaughter weight (p<0.001), and cold carcass weight (p<0.001) were highest in NG males and lowest in CG females. The meat fatty acid composition results showed effects of both genotype and sex on the total n-6 and the total polyunsaturated fatty acid (PUFA) content, as well as the PUFA n-6/PUFA n-3 ratio. Regarding genotype, the total n-6, the total PUFA content and the PUFA n-6/PUFA n-3 ratio were higher in CG, and higher values were found in females. In terms of the lipid metabolism, Δ5–Δ6 desaturase (p = 0.006) was higher in males. The meat oxidative stability results revealed an interaction between genotype, sex and storage time (p<0.001). The highest (13.85 mg/kg) malondialdehyde content was measured in the meat of CG females after 5 days of storage and was presumably related to a higher PUFA content.ConclusionNG had a relatively higher growth rate and meat oxidative stability, whereas the advantage of CG meat is its favourable fatty acid profile characterized by a higher PUFA content.

Vitamin transporters in mice brain with aging.

Its high metabolic rate and high polyunsaturated fatty acid content make the brain very sensitive to oxidative damage. In the brain, neuronal metabolism occurs at a very high rate and generates considerable amounts of reactive oxygen species and free radicals, which accumulate inside neurons, leading to altered cellular homeostasis and integrity and eventually irreversible damage and cell death. A misbalance in redox metabolism and the subsequent neurodegeneration increase throughout the course of normal aging, leading to several age-related changes in learning and memory as well as motor functions. The neuroprotective function of antioxidants is crucial to maintain good brain homeostasis and adequate neuronal functions. Vitamins E and C are two important antioxidants that are taken up by brain cells via the specific carriers αTTP and SVCT2, respectively. The aim of this study was to use immunohistochemistry to determine the distribution pattern of these vitamin transporters in the brain in a mouse model that shows fewer signs of brain aging and a higher resistance to oxidative damage. Both carriers were distributed widely throughout the entire brain in a pattern that remained similar in 4-, 12-, 18- and 24-month-old mice. In general, αTTP and SVCT2 were located in the same regions, but they seemed to have complementary distribution patterns. Double-labeled cell bodies were detected only in the inferior colliculus, entorhinal cortex, dorsal subiculum, and several cortical areas. In addition, the presence of αTTP and SVCT2 in neurons was analyzed using double immunohistochemistry for NeuN and the results showed that αTTP but not SVCT2 was present in Bergmann's glia. The presence of these transporters in brain regions implicated in learning, memory andmotor control provides an anatomical basis that may explain the higher resistance of this animal modelto brain oxidative stress, which is associated with better motor performance and learning abilities in old age.

Effect of different dietary energy and protein sources on antioxidant status, fresh yolk fatty acid profile and microstructure of salted yolks in laying ducks

The study investigated whether different dietary energy and protein sources affect laying performance, antioxidant status, fresh yolk fatty acid profile and quality of salted yolks in laying ducks. In all, 360 19-week-old Longyan ducks were randomly assigned to four diets in a factorial arrangement (2×2). The four diets consisted of two energy sources, corn (CO) or sorghum (SO) and two protein sources, soybean meal (SM) and rapeseed meal with corn distillers dried grains with solubles (RMD), and each treatment contained six replicates of 15 birds each. The experimental diets were isocaloric (metabolizable energy, 10.84 MJ/kg) and isonitrogenous (CP, 17%). The results showed that egg production, average egg weight, egg mass and feed conversion ratio were not affected by diets (P>0.05). Plasma contents of reduced glutathione (GSH), GSH/oxidized glutathione and total antioxidant capacity were lower (P<0.05) in ducks fed the RMD diets compared with those fed SM diets with a substantial increase (P=0.006) in plasma content of malondialdehyde (MDA). Egg yolks from ducks fed SO diets had higher proportions of polyunsaturated fatty acids (PUFA) and lower saturated and monounsaturated fatty acids compared with CO diets (P<0.001). Similarly, ducks fed RMD diets had a higher content of PUFA and n-6/n-3 ratio in fresh yolks (P<0.001), and increased salted yolk MDA, carbonylated proteins content and incidence of hard salted yolks (P<0.05) compared with SM diets. Scanning electron microscopy showed that salted yolks contained rougher polyhedral granules and fewer fat droplets, and were surrounded with a layer of bunchy fibers in ducks fed SO+RMD than those fed CO+SM diet. In conclusion, the current study showed that feeding laying ducks with diets containing SO or RMD reduced antioxidant capacity and increased egg yolk concentrations of PUFA. It appeared that egg yolks from ducks fed these diets were more sensitive to lipid peroxidation and protein oxidation during salting, and reduced the quality of salted yolks.

The effect of age on the fatty acids composition in wild boar (Sus scrofa) hunted in the southwest region of Slovakia

The aim of the study was to analyse the fatty acid profile of wild boar (Sus scrofa) meat. The samples were obtained from the mountain Tríbeč (southwest part of the Slovak Republic). A total of 36 samples in 3 age categories of meat were analysed. The effect of age on the intramuscular (IMF) fat content was analysed. The highest (P &lt; 0.05) IMF content was found in the samples from the youngest animals (18.07%), the lowest (P &lt; 0.05) in the sub-adult animals. Significant (P &lt; 0.05) differences were found in palmitic acid (C16:0). Significant decrease of heptadecanoic acid (C17:0) as an effect of age was analysed in the samples. Of the important fatty acids, the most abundant in all age categories of wild boar were oleic (C18:1 cis 9), palmitic (C16:0), and linolelaidic acid (C18:2 cis n6). Differences in the content of mentioned acids were significant (P &lt; 0.05). In α-linolenic and γ-linoleic acids, non-significant (P &gt; 0.05) differences were detected. Significant differences (P &lt; 0.05) between age categories were found in cis-11-eicosenoic (C20:1 n9) and cis-11,14-eicosadienoic acids (C20:2 n6). Significant differences (P &lt; 0.05) were found in PUFA (polyunsaturated fatty acids), MUFA (monounsaturated fatty acids), and SFA (saturated fatty acids) concentrations. The highest PUFA content was typical for the samples from the oldest animals, MUFA from the sub-adults, and SFA from the youngest wild boar. More significant results were observed in the normalized data with the factor component scores. The wild boar fatty acid profile is significantly affected by age.

Ultrasonic-assisted Aqueous Extraction and Physicochemical Characterization of Oil from Clanis bilineata.

Ultrasound-assisted aqueous extraction (UAAE) was used to extract oil from Clanis bilineata (CB), a traditional edible insect that can be reared on a large scale in China, and the physicochemical property and antioxidant capacity of the UAAE-derived oil (UAAEO) were investigated for the first time. UAAE conditions of CB oil was optimized using response surface methodology (RSM) and the highest oil yield (19.47%) was obtained under optimal conditions for ultrasonic power, extraction temperature, extraction time, and ultrasonic interval time at 400 W, 40°C, 50 min, and 2 s, respectively. Compared with Soxhlet extraction-derived oil (SEO), UAAEO had lower acid (AV), peroxide (PV) and p-anisidine values (PAV) as well as higher polyunsaturated fatty acids contents and thermal stability. Furthermore, UAAEO showed stronger antioxidant activities than those of SEO, according to DPPH radical scavenging and β-carotene bleaching tests. Therefore, UAAE is a promising process for the large-scale production of CB oil and CB has a developing potential as functional oil resource.

Fatty acid composition of maize silages from different hybrids

Fatty acid composition of maize silages from different hybrids

Proximate composition and micronutrient profile of different size groups of hilsa Tenualosa ilisha (Hamilton, 1822) from river Ganga

The Indian shad hilsa, Tenualosa ilisha (Hamilton, 1822) is an important food fish in South-east Asian countries. The fish is rich in oil and known for its high omega-3 polyunsaturated fatty acid (PUFA) content; however information available on the micronutrient profile of this commercially important food fish is limited. The present study investigated the detailed micronutrient profile (mineral and fat soluble vitamins) of different size groups of hilsa. Proximate composition analysis revealed that besides being rich in crude fat (7.91-14.61%), the protein content of this fish is also very high (19.44-21.86%). The macro-minerals potassium, calcium and micro-minerals iron, zinc and the fat soluble vitamins A and E are the dominant micronutrients in different size groups of hilsa. Comparative nutritional evaluation of different size groups of hilsa showed that medium size fish is nutritionally superior to both small and large size groups.

The Marine Fungi Rhodotorula sp. (Strain CNYC4007) as a Potential Feed Source for Fish Larvae Nutrition.

Fish oil is used in the production of feed for cultured fish owing to its high polyunsaturated fatty acid content (PUFA). The over-exploitation of fisheries and events like “El Niño” are reducing the fish oil supply. Some marine microorganisms are considered potentially as alternative fatty acid sources. This study assesses a strain of Rhodotorula sp. (strain CNYC4007; 27% docosahexaenoic acid (DHA) of total fatty acids), as feed for fish larvae. The total length and ribonucleic acid (RNA)/deoxyribonucleic acid (DNA) ratio of Danio rerio larvae was determined at first feeding at six and 12 days old (post-yolk absorption larvae). Larvae fed with microencapsulated Rhodotorula sp. CNYC4007 had a significantly higher RNA/DNA ratio than control group (C1). At six days post-yolk absorption group, the RNA/DNA ratio of larvae fed with Rhodotorula sp. bioencapsulated in Brachionus sp. was significantly higher than control group fed with a commercial diet high in DHA (C2-DHA). Finally, at 12 days post-yolk absorption, the RNA/DNA ratio was significantly higher in larvae fed with Rhodotorula sp. CNYC4007 and C2-DHA (both bioencapsulated in Artemia sp. nauplii) than in control group (C1). These results suggest that Rhodotorula sp. CNYC4007 can be an alternative source of DHA for feeding fish at larval stage, providing a sustainable source of fatty acids.

Effect of different commercial fat sources on brain, liver and blood lipid profiles of rats in growth phase.

To investigate the fatty acid content of different fat sources and evaluate the effect of them on plasma and hepatic lipids and on the fatty acid profile of the brain tissue of Wistar rats. Thirty male albino Wistar rats received for 59 days, the following diets: diet added of margarine with low content of polyunsaturated fatty acids (PUFA); diet added of margarine with high content of PUFA; diet added of butter; diet added of hydrogenated vegetable fat; diet added of soybean oil. Fatty acid profile of the lipid sources, blood and hepatic lipids fractions and fatty acid profile of the brain tissue were determined. Margarine consumption of provided different responses as to concentrations of blood and hepatic lipid fractions. Intake of butter and hydrogenated increased LDL-c/HDL-c ratio, being the steepest increase promoted by hydrogenated vegetable fat, which also raised LDL-c levels expressively. All fats used in the treatments reduced the cerebral concentration of docosahexaenoic acid when compared to soybean oil (control). The different fat sources commonly consumed by population provided different responses in vivo. This is particularly relevant considering the role of these lipids in the incidence and prevention of cardiovascular diseases.

Effects of rumen exposure to anise oil on ruminal fermentation and biohydrogenation of N–3 polyunsaturated fatty acids

This study evaluated the effect of four weeks of microbial exposure to anise oil (ANO) on the fermentation activities of ruminal micro-organisms and the biohydrogenation of n -3 polyunsaturated fatty acids (PUFA). A total of six Hartline ´ Texel cross lambs were used. Three of the lambs were randomly assigned to the basal diet (basal diet group, BDG) and the remaining three lambs were offered basal diet with ANO (anise oil group, AOG) for four weeks. The rumen fluid donor lambs were offered water and hay ad libitum and supplemented with additional 400 g/sheep/day of concentrate plus 2.4 g/sheep/day of ANO (for the AOG). The ANO was thoroughly mixed with the concentrate prior to feeding. The total amount (400 g) of lamb finisher cubes offered per sheep/day was divided into two equal parts (200 g) and fed at 08.00 and 16.00 hours, respectively. After the four weeks’ exposure period, lambs were slaughtered and ruminal fluid (RF) was collected from each of the lambs on BDG and on AOG and used in a 48 h in vitro batch culture system to study the fermentation of a 70: 30 grass hay ( Lolium perenne) and concentrate (lamb finisher) diet. The study was a 2 (batches of rumen fluid: BDG and AOG) 2 (doses of ANO: 0 and 200 mg/L) factorial design experiment. Results showed that total volatile fatty acid (TVFA) in RF extracted from lambs on the BDG (242.0 mM) was similar to that in the AOG (242.2 mM). Concentrations of TVFA in in vitro digests were similar between groups on the BDG (68.6 mM) and on the AOG (66.4 mM), but differed between levels of anise oil (0 versus 200 mg/L). The levels of NH 3 -N were not different (P>0.05) between the RF collected from AOG and BDG. However, in vitro results showed that AOG 200 mg/L induced a 20% decrease on the concentration of NH 3- N in fermentation vessels, relative to BDG 0 mg/L. The in vitro digesta incubated in RF from the AOG (i.e. AOG 200 mg/L) maintained higher concentrations of PUFA (C18:2 n -6 and n -3 PUFA), trans vacceric acid and lower concentration of stearic acid. This suggests that there was no rumen adaptation within the period of trial. This study concludes that anise oil is potentially a useful feed additive to optimise the fatty acid composition of ruminant feedstuffs, if these effects are repeated in meat and milk.

The sunflower oil and the sunflower meal in animal nutrition

The sunflower plant (Helianthus annuus) is an annual herbaceous plant of the Asteraceae family. It is grown primarily for its seeds, the sunflower oil and the sunflower meal obtained from it, but also as an ornamental plant, as feed and as fuel. The sunflower seed is comprised from the husk on the outside and the kernel on the inside, whereas depending on the oil content it is categorised in two varieties, one with low oil content (average 25%) and another with high oil content (40% - 51%). The sunflower oil is high in unsaturated fatty acids, vitamin E and plant sterols and low in saturated fatty acids. The fatty acids composition of the sunflower oil depends mainly on the variety of the sunflower seeds and thus the sunflower oil is categorised in linoleic sunflower oil or classic (with high polyunsaturated fatty acids content), oleic sunflower oil or High-oleic (with a high monounsaturated fatty acids content) and middle oleic sunflower oil or NuSun (with an intermediate oleic acid content). It is marketed as raw oil or refined oil. The sunflower oil is added to the rations of farm animals in order to increase their energy content and to meet their essential fatty acids needs. Nowadays, many researchers study its effect on the composition of milk, meat and eggs produced from farm animals, in order to obtain characteristics more desirable for the human consumers, such as higher concentration of unsaturated omega-3 and omega-6 fatty acids, as well as higher concentration of conjugated linoleic acid (CLA). The sunflower meal is the main byproduct of the sunflower seeds after oil extraction. Sunflower meal may differ in color and texture, as well as in their chemical composition, depending on the variety of the sunflower, the degree of hull removal and the method of treatment. The crude fiber content varies from 12% to 32%, the crude protein from 24% to 44% and the ether extract from 1% to 10%. It also contains a significant amount of vitamins and non-starch polysaccharides. The sunflower oil and the sunflower meal can be used in the nutrition of both monogastric animals and ruminants.

The Effect of Thermal Treatment Method on Fatty Acid Composition in Northern Pike (Esox lucius) Fillets

ABSTRACTThe aim of the present study was to investigate the effect of thermal treatment methods, such as microwave cooking, steaming, and shallow pan-frying on fatty acids composition in northern pike fillets. All methods of thermal treatment increased fat content in the fillets. Microwave cooking decreased the proportion of saturated fatty acids and increased the proportion of total, n-3, and n-6 polyunsaturated fatty acids as compared with fresh fillets. Steam cooking did not affect the proportion of saturated, monounsaturated, and polyunsaturated fatty acids, whereas pan-frying significantly increased the proportion of monounsaturated and n-6 polyunsaturated fatty acids. All cooked fillets, regardless of the thermal treatment used, had acceptable n–6/n–3 ratio; however, microwave cooking enabled fish products to obtain more beneficial n-6/n-3 ratio than frying. Due to high polyunsaturated fatty acids content and low n-6/n-3 ratio, microwave cooking may be recommended for preparing wild pike fillets in households.

The chemical composition of different edible locations (central and edge muscles) of flat fish (Lepidorhombus whiffiagonis)

SummaryThe chemical composition of the different edible locations (central and edge muscles) of a flat fish (megrim, Lepidorhombus whiffiagonis) was comparatively analysed at both body sides. Higher moisture and lower lipid contents were obtained in central muscles than in edge ones. Edge sites showed higher triacylglycerols and sterols contents and lower mean phospholipids values than central muscles. A higher α‐tocopherol presence was observed in the lipid fraction of central muscles than in the edge ones. For both fish sides, fatty acid (FA) analysis showed lower monounsaturated FA and higher polyunsaturated FA contents and ω3/ω6 ratios in central muscles. Presence of essential elements (Co, Cu, Mn, Se, Zn) did not provide differences among sites considered. Concerning toxic elements, As content showed greater levels in central muscles than in their corresponding edge sites for both fish sides, upper zones showed higher mean scores in As, Cd, Cr, Hg, Ni, Pb and V.

Bioprospecting North Atlantic microalgae with fast growth and high polyunsaturated fatty acid (PUFA) content for microalgae-based technologies

Microalgae are considered to be an important and sustainable alternative to fish oil as a source for the polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Due to their health benefits, there is an increasing interest in the commercial application of these fatty acids (FA) to health and dietary products, and to aquaculture feeds. However, FA from microalgae are still expensive to produce compared to fish or plant oils. With only a few microalgal strains being cultivated on a large scale for commercial PUFA production, prospecting for new, robust and fast-growing strains with increased PUFA content is essential in order to reduce production costs. Microalgae from northern high latitudes, exposed to cold temperatures, may be especially promising candidates as previous studies have shown increasing unsaturation of FA in response to decreasing growth temperatures in different microalgae, most likely to maintain membrane fluidity and function. We have designed a screening pipeline, targeting a focused search and selection for marine microalgal strains from extreme North Atlantic locations with high robustness and biomass production, and increased levels of EPA and DHA. The pipeline includes a rational sampling plan, isolation and cultivation of clonal strains, followed by a batch growth experiment designed to obtain information on robustness, growth characteristics, and the FA content of selected isolates during both nutrient replete exponential cultivation and nutrient limited stationary cultivation. A number of clonal cultures (N=149) have been established, and twenty of these strains have been screened for growth and FA content and composition. Among those strains, three showed growth rates ≥0.7d−1 at temperatures of 15°C or below, and high amounts of EPA (>3% DW), suggesting their potential as candidates for large scale production.

English

Rapeseed oil is commonly used as cooking oil in Bangladesh especially in the rural areas and traditionally used with other food items in urban societies. This study evaluated the biochemical properties and chromatographic picturesque of various rapeseed oils namely mustard (wild and hybrid), rai (wild and hybrid) and canola oil in both raw and fried state. The qualitative tests such as acid value, iodine value, peroxide value, saponification value, unsaponifiable matter and Rechert-Meissl value were determined to differentiate the better quality of these consumable oils. Among five types of rapeseed oils, canola oil could be the best choice for consumption due to its lower erucic acid (6%) and high polyunsaturated fatty acids content, while the erucic acid content of mustard (wild), mustard (hybrid), rai (wild) and rai (hybrid) were 51.56, 64.82, 56.31 and 67.98% respectively. Canola oil also had the lowest level of acid value, peroxide value, saponification value and Reichert Meissl value but higher level of iodine value. On the other hand, rai (hybrid) fried oil was the lowest quality of consumable oil in comparison with other forms of rapeseed oils. Raw seed oils were also better than fried oils. Key words: Rapeseed oils, qualitative test, gas-liquid chromatography (GLC).