Influence Of Lipid Content Research Articles

The influence of lipid content and taxonomic affiliation on methane and carbon dioxide production from phytoplankton biomass in lake sediment

AbstractThe greenhouse gases methane (CH4) and carbon dioxide (CO2) are end products of microbial anaerobic degradation of organic matter (OM) in lake sediments. Although previous research has shown that phytoplankton lipid content influences sediment methanogenesis, current understanding on how OM quality affects methanogenesis is still limited. Such information is needed to more accurately assess how lake greenhouse gas emissions may change in response to anthropogenic activities. We cultured 11 phytoplankton species from five classes and studied how taxonomic identity, C : N ratio, lipid content, and fatty acid composition of phytoplankton biomass affects the CH4 and net CO2 production in anaerobic lake sediments with an incubation experiment that lasted > 100 d. The carbon‐normalized potential CH4 (0.09–0.23 μmol mg C−1 d−1) and net CO2 (0.09–0.28 μmol mg C−1 d−1) production rates were not related to phytoplankton taxonomic affiliation (e.g., class, species), C : N ratio, or fatty acid composition of algal biomass. Methane or net CO2 production potentials did not increase with higher lipid content (10–30%); however, total fatty acid content had a weak correlation with CH4 production potential. In contrast to previous research, our results suggest that lipid content is of minor importance in determining methanogenesis rates from the biomass of multispecies phytoplankton communities settling on sediments. The decrease in CO2 concentration and the correlation between stable carbon isotope signatures of CH4 and molar ratio of CH4 and CO2 at the end of the experiment may indicate that importance of hydrogenotrophic methanogenesis, which uses CO2 when other substrates become limiting, increased during the long incubation.

The influence of lipid content and pretreatment methods on protein conformation in fish (capelin, Mallotus villosus) during smoking and drying.

The influence of lipid content and pretreatment methods (blanching and brining) on proteins conformation in fish (Capelin, Mallotus villosus) during drying and smoking were assessed. Soluble protein fractions were examined through changes in salt‐soluble proteins, sulfhydryl groups, and disulfide bonds contents. The salt level and moisture content were also evaluated. Conformational changes in muscle protein were significant (p < 0.05) after blanching and during initial drying when moisture content and dryness rates were high. Salt‐soluble proteins and total sulfhydryl groups contents reduced, whereas available sulfhydryl group and disulfide bonds contents intensified. The conformational changes were explained by muscle protein denaturation and aggregation ascribed to high temperature and dehydration during processing. The study reports fish protein denaturation to have reduced protein solubility as well as the nutritional value (loss of thermolabile compounds) and yield after smoking. More so, protein aggregation that was significantly (p < 0.05) higher in dried blanched fish could have reduced the dried fish sensory quality. Blanching pretreatment is thus not suitable for commercial capelin drying. Lipids were found to have protective effect against fish protein conformation.

Influence of lipid content and stirring behaviour on furan and furan derivative exposure in filter coffee

Coffee has been determined as the dominant source of furan within an adult’s diet. This study investigates the influence of coffee condiment use and stirring on the retention of furan. Three condiment lipid compositions were investigated, 0%, 3.5% and 35%, and kept at either 4 °C, 20 °C or 70 °C before addition to a freshly brewed cup of filter coffee which was subsequently mechanically stirred at three intensities, not stirred and moderately or heavily stirred. While five furans were monitored, furan, 2-methylfuran, 3-methylfuran, 2,5-dimethylfuran and 2,3-dimethylfuran, only two were quantifiable: furan and 2-methylfuran. Increasing condiment lipid concentration significantly increased retention of furan and 2-methylfuran, whereas stirring the coffee significantly increased furan release. A condiment temperature of 70 °C was found to significantly increase furan release.

Influence of lipid content and dilution on properties and stability of nanostructured lipid carriers (NLCs) prepared from rambutan (Nephelium lappaceum L.) kernel fat and evaluation of their β-carotene loading capacity

The effects of lipid content and dilution on the properties and stability of nanostructured lipid carriers (NLCs) prepared from rambutan (Nephelium lappaceum L.) kernel fat were investigated. The β-carotene-loading capacity of the NLCs was also evaluated. NLCs containing various lipid phase concentrations (5, 10, and 15 wt%) were prepared using Tween 80 as the emulsifier with a lipid to emulsifier weight ratio of 1:0.2. The results showed that an increase in the lipid content up to 15 wt% had no effect on the zeta-potential, particle size and polydispersity index but resulted in a higher particle density. All samples showed no phase separation during storage at 25 °C for 28 days; however, the relative recrystallization index (RRI) increased. Dilution of concentrated NLC (15 wt%) to a lower lipid content (5 and 10 wt%) produced no differences in the particle characteristics and stability during storage. NLCs loaded with β-carotene at different concentrations (0, 0.5, and 1 wt% of the lipid phase) exhibited desirable characteristics and had high encapsulation efficiency (∼97%) over 28 days of storage. These results demonstrated that NLC prepared from rambutan kernel fat can be used to entrap lipophilic bioactive components which could be used as ingredients in functional food products.

Influence of lipid content and packaging methods on the quality of dried capelin (Mallotus villosus) during storage.

Capelin annual catch exceeds half a million tons in Iceland, with only a small quantity (<20%) of female with roe used for human food. There is a potential to use dried male capelin as a new product for human consumption, but its lipid content varies considerably (4-20% body weight). Earlier studies were more concentrated on the influence of drying conditions than the influence of storage conditions on the quality of dried fish, as dried fish are usually considered to be stable and safe during storage. Three batches of dried male capelin differing in lipid content were packaged and studied during 5months storage at 22±2°C to establish appropriate lipid content at harvesting and product packaging method. Lipid composition, lipid hydrolysis and oxidation, sensory attributes and microbial activity were evaluated. Batches differed in composition and stability, with low lipid capelin constituting higher proportion of polyunsaturated fatty acids (22% lipid) than high lipid (18% lipid) capelin. Lipid oxidation was influenced by lipid content and packaging method, as accelerated oxidation occurred in high lipid and open packed capelin. Lipid hydrolysis was less influenced by packaging and was greater in low lipid capelin. High lipid capelin in open bags scored the highest for rancid odor. All batches were micro-biologically stable with colony-forming unit counts increasing less than log 1 (log 5-6) during 5months storage.

Life cycle assessment of microalgae-based aviation fuel: Influence of lipid content with specific productivity and nitrogen nutrient effects

The aim of this work is to compare the life cycle assessments of low-N and normal culture conditions for a balance between the lipid content and specific productivity. In order to achieve the potential contribution of lipid content to the life cycle assessment, this study established relationships between lipid content (nitrogen effect) and specific productivity based on three microalgae strains including Chlorella, Isochrysis and Nannochloropsis. For microalgae-based aviation fuel, the effects of the lipid content on fossil fuel consumption and greenhouse gas (GHG) emissions are similar. The fossil fuel consumption (0.32–0.68MJ·MJ−1MBAF) and GHG emissions (17.23–51.04gCO2e·MJ−1MBAF) increase (59.70–192.22%) with the increased lipid content. The total energy input decreases (2.13–3.08MJ·MJ−1MBAF, 14.91–27.95%) with the increased lipid content. The LCA indicators increased (0–47.10%) with the decreased nitrogen recovery efficiency (75–50%).

Influence of Lipid Content and Lipoxygenase on Flavor Volatiles in the Tomato Peel and Flesh

Ten different varieties of tomatoes were separated into peel and flesh and each portion was measured separately. Headspace volatiles were measured in real time using selected ion flow tube mass spectrometry. Lipoxygenase activity was measured using the adsorption of conjugated dienes formed by lipoxygenase. Lipid was extracted and fatty acids were quantified using a gas chromatograph. Volatiles were significantly greater in the peel than flesh when there was a significant difference. The lipoxygenase activity of flesh and peel correlated with the volatiles produced by the lipoxygenase pathway. There was no correlation with other volatiles, which are not dependent on lipid oxidation by lipoxygenase. The lipoxygenase activity, total fatty acid content, and linolenic acid of the peel were greater than the flesh, which is directly related to an increase in fresh, green volatiles. Addition of exogenous lipoxygenase had no effect on lipoxygenase-derived volatiles formed. The addition of linoleic acid caused an increase in hexanal, 1-hexanol, and (E)-2-heptenal in the flesh and (E)-2-heptenal in the peel. Stored unrefrigerated peel had higher volatile concentrations, whereas refrigerated peel had significantly lower concentration than day 0. Storage decreased lipoxygenase activity in the unrefrigerated and refrigerated peel, but had no effect on the fatty acid content. Overall, linolenic acid was the most important to the formation of headspace volatiles, but lipoxygenase activity and unknown factors are also important. The peel of a tomato is most beneficial to the production of volatiles associated with the fresh aroma of tomatoes; therefore, it should be used in the processing of tomato products to produce a fresh, green aroma rather than being removed. Knowledge of the effects of lipoxygenase activity, total fatty acid content, and fatty acid profile on flavor volatiles will allow for better selection of a variety for raw consumption.

Bioaccumulation of persistent organic pollutants (POPs) in fish species from Lake Koka, Ethiopia: The influence of lipid content and trophic position

The concentrations and bioaccumulation of persistent organic pollutants (POPs) were determined in four fish species from Lake Koka, Ethiopia, representing 2–3 levels in the food chain of the lake. Dichlorodiphenyltrichloroethanes (DDTs), endosulfans, polychlorinated biphenyls (PCBs) and chlorpyrifos were identified, with DDTs as the most predominant pesticide, with concentration ranging from 0.05 to 72.53 ng g −1 wet weight (ww). All fish tissue samples collected from different species of the lake contained residues of DDTs. The maximum level of DDTs was found in the fattiest, African sharptooth catfish ( Clarias gariepinus) sampled from the lake, with a mean concentration of 15.15 ng g −1ww. The significant (P < 0.05) relationship between concentrations of DDTs and δ 15N indicates that DDTs biomagnified in the food web of the lake. The 4,4′-DDE to 4,4′-DDT ratio in Oreochromis niloticus (0.6) and Cyprinus carpio (0.5) were below 1, indicating ongoing use of DDTs in the study area and recent exposure of these fish species.

Influence of Lipid Content and Oxidation State of Chylomicron Remnants on Endothelial Cell Signalling And Function

Influence of Lipid Content and Oxidation State of Chylomicron Remnants on Endothelial Cell Signalling And Function

Structure and stability of crustacean lipovitellin: Influence of lipid content and composition

Lipovitellin (LV) is essential in crustacean eggs for embryo viability and development. Two LV were isolated from eggs of Macrobrachium borellii. corresponding to early (LVe ) and late (LVl) embryo developing stages. They differ in lipid composition but not in lipid/protein ratio or apoprotein composition. Structural information was obtained by fluorescence spectroscopy, far-UV circular dichroism, partial trypsinolysis and electron microscopy applied to LVe and LVl and two partially delipidated forms of LVe generated by phospholipase A2 (LVp) or Triton X-100 (LVt) treatment. All LV forms contained two apoprotein subunits of 94 and 112 kDa, being the 112k Da subunit more accessible to trypsinolysis in all. Only in LVp, different cleavage sites appeared. Secondary structure was similar in LVe and LVl, but LVp and LVt showed a small increase in beta-sheet at expense of alpha-helix. Electron microscopy revealed a spheroidal morphology in all LV and a decreased size in LVp. Delipidated LVs were more resistant to denaturation with guanidinium-HCl. Acrylamide quenching of tryptophan fluorescence was more efficient in delipidated LVs, probably due to apolipoprotein rearrangement, as reinforced by fluorescence anisotropy. It is concluded that LV stability, shape, and apoprotein conformation is not largely affected by the changes in lipid composition that take place during embryogenesis.

Influence of lipid content on pork sensory quality within pH classification1

The objective of this project was to determine the contribution of lipid content to textural and sensory properties of fresh pork within defined pH classifications. Pigs (n = 1,535; from 248 sires and 836 dams) from the 1991, 1992, and 1994 National Barrow Show Sire Progeny Test were used in this study. The test included purebred Berkshire (107), Chester White (113), Duroc (249), Hampshire (220), Landrace (165), Poland China (101), Spotted (181), and Yorkshire (399) barrows (901) and gilts (634). Diets were uniform across breeds within test. The halothane (Hal 1843) genotype (1346 NN and 189 Nn) was determined. Pigs were slaughtered at 105 kg of BW, and samples of the LM were obtained from each carcass at the 10th rib. Star probe, sensory traits, and lipid content were determined on the LM from each pig. A pH classification of LM was assigned as follows: class A, > 5.95, n = 186; class B, > or = 5.80 to 5.95, n = 236; class C, > or = 5.65 to 5.80, n = 467; class D, > or = 5.50 to 5.65, n = 441; class E, < 5.50, n = 205. Data were analyzed using a mixed linear model including pH classification, test, sex, halothane genotype, breed, and breed x sex interaction as fixed effects, with sire and dam within breed included as random effects. Correlations were determined within pH class. Lipid content was a significant source of variation for models predicting star probe values in class C and D and for chewiness in class B, C, and D. Increasing lipid content tended to increase sensory tenderness in pH class D. Sensory tenderness was not affected by lipid content in pH class A, B, or E. Lipid content was not a significant source of variation for juiciness scores within any pH class. Intramuscular lipid is correlated with sensory texture traits primarily in classes C and D. Within class C and D, correlations indicate that increasing lipid content is associated with high sensory tenderness, low sensory chewiness, and low star probe values. It is concluded that lipid content is a small source of variation in texture and tenderness of pork loin with pH between 5.80 and 5.50, but not at a greater or lesser pH.

Influence of lipid content of testmeal on gastrointestinal handling and metabolic partitioning of dietary lipid in young men.

Influence of lipid content of testmeal on gastrointestinal handling and metabolic partitioning of dietary lipid in young men.

Overwinter Survival and Lipid Content of Walleye Fingerlings

Abstract We investigated the influence of lipid content on survival of age-0 walleyes Stizostedion vitreum during the winter of 1994–1995. We conducted a starvation experiment in three hatchery ponds with four groups of walleye fingerlings with different mean lipid contents (15.3–20.3% of dry weight). Overwinter survival was high and not significantly different among groups (77.6–94.1%). In three of four study lakes, electrofishing catch rates of young walleyes in the fall and spring were not significantly different; so overwinter mortality was not substantial. Young walleyes grew during the winter in these three lakes. Catch rate declined significantly from fall to spring in one lake, but mortality was not size selective. We concluded that lipid content should have little effect on overwinter survival of age-0 walleyes in lakes.