Effect Of Lipid Content Research Articles

Effect of Lipid Content on Anaerobic Digestion Process and Microbial Community: Review Study

The indiscriminate release of significant amounts of food waste, fat oil and grease, and sewage sludge (SS) into the environment causes severe contamination in many nations. There are numerous potential treatment methods to cope with organic wastes, but anaerobic digestion is currently widely accepted to handle different kinds of biological waste. One of the pillars supporting anaerobic digester biogas production increase in treatment plants is the use of fats in the wastewater. However, it has been claimed that high-fat wastes, particularly mono-digestion in the anaerobic reactor, inhibit acetoclastic and methanotrophic bacteria delay the formation of gas even more, and overtax the system. The aim of this review is to review several publications that dealt with the effect of LCFs and FOG on AD performance and associated methane production and microbial communities, as well as the mechanism of LCFA generation and its inhibitory effect on anaerobic digestion performance, and also addressed the improvement of system efficiency using co-digestion with lipid wastes.

Effect of Lipid Content on Anaerobic Digestion Process and Microbial Community: Review Study

The indiscriminate release of significant amounts of food waste, fat oil and grease, and sewage sludge (SS) into the environment causes severe contamination in many nations. There are numerous potential treatment methods to cope with the organic wastes, but anaerobic digestion is currently widely accepted to handle different kinds of biological waste. One of the pillars supporting anaerobic digester biogas production increase in treatment plants is the use of fats in the wastewaters. However, it has been claimed that high-fat wastes, particularly mono-digestion in the anaerobic reactor, inhibits acetoclastic and methanotrophic bacteria, delays the formation of gas even more, and overtaxes the system. This paper examines the research on the impact of lipids on biogas enhancement, reactor inhibition, impact on the microbial communities, and co-digestion with lipids in the anaerobic digestion process.

Effect of Lipid Content on Anaerobic Digestion Process and Microbial Community: Review Study

The indiscriminate release of significant amounts of food waste, fat oil and grease, and sewage sludge (SS) into the environment causes severe contamination in many nations. There are numerous potential treatment methods to cope with the organic wastes, but anaerobic digestion is currently widely accepted to handle different kinds of biological waste. One of the pillars supporting anaerobic digester biogas production increase in treatment plants is the use of fats in the wastewaters. However, it has been claimed that high-fat wastes, particularly mono-digestion in the anaerobic reactor, inhibits acetoclastic and methanotrophic bacteria, delays the formation of gas even more, and overtaxes the system. This paper examines the research on the impact of lipids on biogas enhancement, reactor inhibition, impact on the microbial communities, and co-digestion with lipids in the anaerobic digestion process.

Effect of Lipid Contents and Process Parameters on the Physicochemical, Rheological, Calorimetric and Structural Properties of an Extruded Canine Food

Effect of Lipid Contents and Process Parameters on the Physicochemical, Rheological, Calorimetric and Structural Properties of an Extruded Canine Food

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.

Effect of lipid content on oxidation susceptibility of duck meat

Effect of lipid content on oxidation susceptibility of duck meat

Influence of Lipid Content and Blanching on Capelin (Mallotus villosus) Drying Rate and Lipid Oxidation under Low Temperature Drying

AbstractThe drying characteristics and lipid oxidation in brined and blanched whole capelin were studied during controlled low temperature drying to establish the influence of lipid content and blanching. Drying characteristics (moisture content, drying rate and water activity) and lipid oxidation indicators (PV, TBARS and color) were determined. Drying was influenced by blanching as well as the lipid level. Moisture content at equilibrium for brined and blanched high lipid dried capelin was 20 and 13% (aw, 0.69 and 0.62), whereas counterpart low lipid groups had 19 and 11% (Aw, 0.67 and 0.59) accordingly after 184 h of drying. Changes in PV, TBARS and color were observed as drying progressed with brined capelin exhibiting more stability in the attributes than blanched capelin. Blanched and low lipid capelin dried faster; however, blanching resulted to increased yellowness color making it unpopular for capelin drying.Practical ApplicationsCapelin is one of the important pelagic fisheries in northern hemisphere with sustained catch stock; nonetheless, small quantities are used fresh, dried or salted for human food. In this paper, effects of lipid content and blanching on capelin drying characteristics and lipid oxidation are assessed. The study shows that lipid content affected drying characteristics as capelin with low lipid recorded reduced moisture at equilibrium. Blanching as practiced prior to drying of other small fish products in the intended markets for dried capelin affected capelin muscle water holding thereby enhancing drying but led to undesirable yellowness color and oxidation. It was recommended that dried brined capelin with low lipid content is tested for consumer acceptability prior to commercialization.

Distribution and composition pattern of polycyclic aromatic hydrocarbons in different tissues of sturgeons collected from Iranian coastline of the Caspian Sea

The levels of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in the liver, kidney, gills and muscle tissues of Persian sturgeon (Acipenser persicus; n=16), and Stellate sturgeon (Acipenser stellatus; n=7) collected from coastal waters of the South Caspian Sea from March and April 2011. The distribution and composition pattern of PAHs in the different tissues of sturgeons, and the effects of lipid content in sturgeon tissues and the octanol–water partition coefficient (Kow) of PAHs congeners on them were analyzed. The levels of total PAHs in the various tissues of Persian sturgeon and Stellate sturgeon ranged from 2.095 to 6.587 and 1.942 to 6.206μgg−1dw, respectively. Stellate sturgeon showed significantly higher levels of heavy PAHs (⩾4-rings) than Persian sturgeon. The analysis has revealed a high degree of differential accumulation of the studied PAHs in the tissues of the both species. Low molecular weight PAHs predominated in the sturgeons, accounting for 81.89% of the total PAHs. Among the sixteen tested PAHs, naphthalene was the most dominant congener, followed by phenanthrene and fluorene. The PAHs levels and distribution in the tissues of sturgeons are dependent on both the Kow of PAH congeners and the lipid content in these tissues. There was a significant positive relationship (r=0.868, p<0.005) between lipid content and PAHs levels. The statistically significant negative relationships (p<0.01) were found between log Kow and log-transformed PAHs levels for muscle tissues of both sturgeon species.

Stable isotope enrichment in laboratory ant colonies: effects of colony age, metamorphosis, diet, and fat storage

AbstractEcologists use stable isotopes to infer diets and trophic levels of animals in food webs, yet some assumptions underlying these inferences have not been thoroughly tested. We used laboratory‐reared colonies of Solenopsis invicta Buren (Hymenoptera: Formicidae: Solenopsidini) to test the effects of metamorphosis, diet, and lipid storage on carbon and nitrogen stable isotope ratios. Effects of metamorphosis were examined in ant colonies maintained on a control diet of domestic crickets and sucrose solution. Effects of a diet shift were evaluated by adding a tuna supplement to select colonies. Effects of lipid content on stable isotopes were tested by treating worker ants with polar and non‐polar solvents. δ13C and δ15N values of larvae, pupae, and workers were measured by mass spectrometry on whole‐animal preparations. We found a significant effect of colony age on δ13C, but not δ15N; larvae, pupae, and workers collected at 75 days were slightly depleted in 13C relative to collections at 15 days (Δδ13C = −0.27‰). Metamorphosis had a significant effect on δ15N, but not δ13C; tissues of each successive developmental stage were increasingly enriched in 15N (pupae, +0.5‰; workers, +1.4‰). Availability of tuna resulted in further shifts of about +0.6‰ in isotope ratios for all developmental stages. Removing fat with organic solvents had no effect on δ13C, but treatment with a non‐polar solvent resulted in enriched δ15N values of +0.37‰. Identifying regular patterns of isotopic enrichment as described here should improve the utility of stable isotopes in diet studies of insects. Our study suggests that researchers using 15N enrichment to assess trophic levels of an organism at different sites need to take care not to standardize with immature insect herbivores or predators at one site and mature ones at another. Similar problems may also exist when standardizing with holometabolous insects at one site and spiders or hemimetabolous insects at another site.

Lipid extraction effects on stable isotope values (δ13C and δ15N) of elasmobranch muscle tissue

Given the known effect of lipid content on δ13C values and the potential effect of urea on δ15N values, examining the effects of lipid extraction, which can potentially extract both, is of particular importance for elasmobranch isotope ecology. Through analysing paired δ13C, total %C, δ15N, total %N and C:N values of non-lipid extracted (BULK) and lipid extracted (LE) muscle samples from twenty-one elasmobranch species, we assessed whether lipid extraction was required: (i) to remove lipids given reported low lipid content and, (ii) to determine if δ15N values were affected and whether this relates to the retention of isotopically light urea by elasmobranchs. The mean (±SD) δ13C values of eight out of twenty-one species significantly increased following lipid extraction with two species, the Greenland (Somniosus microcephalus) and whale (Rhincodon typus) shark, showing a marked increase (5.0±0.4‰ and 3.3‰, respectively). The mean (±SD) and maximum increase in δ13C values were 0.6±1.2‰ and 5.9‰, respectively. For δ15N data, thirteen species showed a significant increase following lipid extraction and a concomitant reduction in total percent nitrogen (%N). The C:N ratio for these species also increased from unexpectedly low values of <3.0 to ~3.0, the value expected for pure protein. The mean and maximum observed increase in δ15N values were 0.6±0.6‰ and 2.3‰, respectively. There was no effect of increasing animal size on δ13C and δ15N difference (LE–BULK) for the two species examined. Field sampled animals (sampled immediately upon capture in the marine environment) showed a greater δ15N difference than animals sampled in the laboratory (sampled several hours after capture in the marine environment) (1.0±0.5‰ and 0.4±0.4‰ respectively), while estuarine sampled animals (sampled immediately) showed the smallest difference (0.1±0.6‰). The δ13C data demonstrate that lipid extraction is required to remove lipids from elasmobranch muscle tissue given both intra- and inter- species variability. In addition, the increase in δ15N values, decrease in %N and increase in C:N ratio indicate that lipid extraction is removing soluble urea. Given lower δ15N diet-tissue discrimination factors for large marine predators, removal of urea is required to elucidate accurate trophic position estimates and relative food web position of elasmobranchs and for diet reconstruction. It is recommended that investigators undertake lipid extraction trials on elasmobranch muscle tissue to determine effects on δ13C and δ15N values on a species-by-species basis.

Effect of Lipid Content and Components on Cooking Quality and Their Re-sponse to Nitrogen in Milled &lt;I&gt;Japonica&lt;/I&gt; Rice

Effect of Lipid Content and Components on Cooking Quality and Their Re-sponse to Nitrogen in Milled &lt;I&gt;Japonica&lt;/I&gt; Rice

Effect of Lipid Content and Components on Cooking Quality and Their Responses to Nitrogen in Milled Japonica Rice

The objective of this study was to understand the relationship between cooking quality and lipid content and components in milled rice of different cultivars, and the regulation of nitrogen on lipid quality in japonica rice (Oryza sativa L.). Under 7 nitrogen conditions with 4 total nitrogen levels and 2 split ratios, the RVA parameters and contents of crude lipid, lipid components, and amylose were assayed in 6 cultivars. Genotype significantly affected the content and components of lipid in milled rice. The milled rice of small-panicle cultivars had higher contents of crude lipid and starch lipid and lower non-starch lipid in milled rice than that of the large-panicle cultivars. The effect of nitrogen on lipid content and components in milled rice was smaller than that of genotype, and varied among genotypes. The content of crude lipid was significantly and negatively correlated with breakdown value, and the content of starch lipid was significantly and negatively correlated with amylose content, setback value, and consistency viscosity. The results indicate that rice cooking quality can be promoted through cultivar improvement aiming at increasing starch lipid content in milled rice.

Residual levels and health risk of polycyclic aromatic hydrocarbons in freshwater fishes from Lake Small Bai-Yang-Dian, Northern China

The residual levels of polycyclic aromatic hydrocarbons (PAHs) in the liver, brain, gill and muscle tissues of four common edible freshwater fish species including crucian carp , snakehead fish , grass carp and silver carp collected from Lake Small Bai-Yang-Dian in northern China were measured by GC–MS. The distribution and composition pattern of PAHs in the fish tissues, and the effects of lipid contents in fish tissues and the octanol–water partition coefficient (Kow) of PAHs congeners on them were analyzed. The human health risk of PAHs though fish consumptions was estimated. The following results were obtained: (1) The average residual levels of total PAHs (PAH 16) on wet weight base in the different tissues of each fish species ranged from 4.764 to 144.254 ng/g ww. The differences in the average residual levels on wet weight base for PAH 16 within four fish species were not statistically significant ( P > 0.05); however, these within four fish tissues were statistically significant ( P < 0.01). (2) There were very similar distribution patterns of PAH congeners among both the fish tissues and the fish species, as indicated by statistically significant positive interrelationships ( R = 0.58–0.97, P < 0.01 or P < 0.05). Low molecular weight (LMW) PAHs predominated the distribution in the fish tissues, accounting for 89.97% of total PAHs. Phe was the most dominant component, according for 37.79% of total PAHs, followed by Ant (18.59%), Flo (12.59%), Nap (10.79%), Fla (9.82%) and Pyr (6.43%). (3) The PAHs residues and distribution in the fish tissues are dependent on both the Kow of PAH congeners and the lipid contents in the fish tissues. There was a significant positive relationship ( R = 0.7116, P < 0.0001) between lipid contents and PAHs residual levels. The statistically significant negative relationships ( P < 0.05) were found between LogKow and log-transformed PAHs contents on wet weight base for all fish tissues except for the muscle tissue of snakehead fish, the brain and liver tissues of crucian carp. (4) The risk levels of total PAHs were lower than 10 −5 for the muscle tissues of four studied fish species and for the brain tissues of grass carp and snakehead fish; while these were higher than 10 −5 for the brain tissues of crucian carp and silver carp. The risk levels of total PAHs in the liver tissues of four studied fish species except for snakehead fish exceeded 10 −5 for 2–4.5 times. However, the potency equivalent concentration (PEC) of total PAHs in four studied fish tissues were still lower than the maximum permissible BaP limits for crops and baked meat and for plants in the national criterions. The distributions of PAH congeners in fish were well simulated by a level III fugacity model, especially for low molecule weight PAHs.

The effect of lipid content on the elemental composition and energy capacity of yeast biomass

Oleaginous yeasts (18 strains) were grown in ethanol media under various cultivation conditions (33 biomass samples). It was found that lipid and lipid-free fractions of dry biomass have elemental composition and biomass reductivity very close to values which can be considered as biological constants. The energy content of dry biomass strongly depended on the total lipid content. When the lipid content was 64%, the energy value of dry biomass reached 73% of diesel oil; therefore, oleaginous microorganisms can be a promising source of biodiesel fuel. The approach used in this work makes it possible to determine the energy value of biomass by its elemental composition without application of laborious and expensive calorimetric measurements of combustion heats.

Recovery and upgrading bovine rumen protein by extrusion: Effect of lipid content on protein disulphide cross-linking, solubility and molecular weight

Bovine rumen protein with two levels of residual lipids (1.9% or 3.8%) was subjected to thermoplastic extrusion under different temperatures and moisture contents. Protein solubility in different buffers, disulphide cross-linking and molecular weight distribution were determined on the extrudates. After extrusion, samples with 1.9% residual lipids content had a higher concentration of protein insoluble by undetermined forces, irrespective of feed moisture and processing temperature used. Lipid content of 3.8% in the feed material resulted in more protein participating in the extrudate network through non-covalent interactions (hydrophobic and electrostatic) and disulphide bonds. A small dependency of the extrusion process on moisture and temperature and a marked dependency on lipid content, especially phospholipid, was observed, Electrophoresis under non-reducing conditions showed that protein extrusion with low feed moisture promoted high molecular breakdown inside the barrel, probably due to intense shear force, and further protein aggregation at the die end.

Stable isotope determination in wild and farmed gilthead sea bream ( Sparus aurata) tissues from the western Mediterranean

Stable isotopes of carbon and nitrogen ( δ 13C and δ 15N) have been determined in wild and farmed gilthead sea bream ( Sparus aurata) samples of white and red muscle, liver, gills and gonads. First, δ 13C and δ 15N values were determined in samples with and without lipid removal to check the possible effect of lipid content on the stable isotope values of the different tissues studied. Differences were found for δ 13C in all tissues studied apart from white muscle of wild fish, the tissue with the lowest lipid content. For δ 15N values no differences were found in wild fish tissues. Liver from farmed fish showed lower δ 15N value after lipid removing. Further conclusions were based on results obtained from lipid-free samples. δ 13C of cultured fish tissues showed a mean depletion of 2.9 ± 0.4‰ compared to wild specimens, suggesting different sources of carbon in the diet, probably due to the feed used during sea-cage culture. Cultured gilthead sea bream tissues were significantly more enriched in nitrogen than wild specimens by an average of 1.5 ± 0.2‰ in white muscle, indicating a slight increase in the trophic level. Determination of stable isotope signatures of gilthead sea bream tissues allows clear discrimination between wild and cultured sea bream, and characterisation of differences in diet and feeding conditions in any tissue studied.

Getting to the fat of the matter: models, methods and assumptions for dealing with lipids in stable isotope analyses

Within an organism, lipids are depleted in (13)C relative to proteins and carbohydrates (more negative delta(13)C), and variation in lipid content among organisms or among tissue types has the potential to introduce considerable bias into stable isotope analyses that use delta(13)C. Despite the potential for introduced error, there is no consensus on the need to account for lipids in stable isotope analyses. Here we address two questions: (1) If and when is it important to account for the effects of variation in lipid content on delta(13)C? (2) If it is important, which method(s) are reliable and robust for dealing with lipid variation? We evaluated the reliability of direct chemical extraction, which physically removes lipids from samples, and mathematical normalization, which uses the carbon-to-nitrogen (C:N) ratio of a sample to normalize delta(13)C after analysis by measuring the lipid content, the C:N ratio, and the effect of lipid content on delta(13)C (Deltadelta(13)C) of plants and animals with a wide range of lipid contents. For animals, we found strong relationships between C:N and lipid content, between lipid content and Deltadelta(13)C, and between C:N and Deltadelta(13)C. For plants, C:N was not a good predictor of lipid content or Deltadelta(13)C, but we found a strong relationship between carbon content and lipid content, lipid content and Deltadelta(13)C, and between and carbon content and Deltadelta(13)C. Our results indicate that lipid extraction or normalization is most important when lipid content is variable among consumers of interest or between consumers and end members, and when differences in delta(13)C between end members is <10-12 per thousand. The vast majority of studies using natural variation in delta(13)C fall within these criteria. Both direct lipid extraction and mathematical normalization reduce biases in delta(13)C, but mathematical normalization simplifies sample preparation and better preserves the integrity of samples for delta(15)N analysis.

The residual dynamic of polycyclic aromatic hydrocarbons and organochlorine pesticides in fishponds of the Pearl River delta, South China

Hong Kong and South China are the most developed regions within China. The industrialization in these areas has resulted in severe environmental problems. Sediment and biotic samples including tilapia ( Oreochromis mossambicus), bighead carp ( Aristichthys nobilis), grass carp ( Ctenopharyngodon idellus), crucian carp ( Carassius auratus) and mandarin fish/fresh water grouper ( Siniperca chuatsi) were collected from different fishponds in the Pearl River Delta (Tanzhou, Sanjiao, Guangzhou, Shipai, Changan and Mai Po) for the analysis of polycyclic aromatic hydrocarbons (PAHs) and organochlorine (OC) pesticides. Mandarin fish, which belongs to the highest trophic level, accumulated the highest concentrations of PAHs and DDTs among all fish species. The levels of DDTs in fish samples ranged from 1.5 to 62 ng g −1 (wet wt.), with more than 30% of the fish samples exceeding the limit of 14.4 ng g −1 (wet wt.) for human consumption recommended by US EPA (2000). Levels of PAHs in fish samples ranged from 1.91 to 224.03 ng g −1 (wet wt.), but the potency-weighted total concentrations of PAHs in all muscle tissues were below the guideline value of 0.67 ng g −1 (wet wt.) for human consumption set by US EPA (2000). The guideline value calculated was based on a tissue consumption rate of 142.2 g day −1 (4–5 meals per week), which is a more protective rate for populations with a high consumption of fish, like Chinese and Asians. The effect of lipid content in PAHs and DDTs accumulation in fish tissue was not significant in general.

Water transfer analysis in pork meat supported by NMR imaging

NMR proton density imaging was used to study isothermal and unidirectional drying of pork semi membranosus muscle samples at temperatures of 12, 16 and 20 °C. An independent calibration of the transversal relaxation time T 2 as a function of the moisture content was carried out to convert the signal amplitude into moisture content. Due to spatial heterogeneity in drying, 2D images were needed to assess the evolution of 1D moisture profiles. The relationship between the effective water diffusivity ( D) was calculated in function of water content ( X) using the Boltzman transformation which needs no a priori on the relationship D= f( X); the effect of lipid content, temperature and fibre direction on this relationship were also studied. In all cases a decrease in water content brought about a decrease in D. A slight increase in lipid content led to a dramatic decrease in D. The fibre direction relative to water movement had a negligible effect. No significative differences in D between the three temperatures were observed, due to variability in the chemical composition of the samples.

Residues of organochlorines in sediments and tilapia collected from inland water systems of Hong Kong.

The levels and patterns of organochlorines including DDTs, HCHs, and PCBs were investigated in sediments and tilapia (Tilapia mossambica) collected from inland water systems [Tai Wai (S1), Fo Tan (S2), Siu Lek Yuen (S3), Tai Po (S4), and Tai Wo (S5)] in the New Territories of Hong Kong. Sediment and tilapia samples were also collected from two fish ponds for comparison. The ranges of DDTs, HCHs, and PCBs in river sediments were 2.82-8.63 ng/g (DW), 0.05-2.07 ng/g (DW), and 43-461 ng/g (DW), respectively. All these values were significantly higher (p < 0.05) than the pond sediments. Low chlorinated congeners (especially mono-, tri-, and tetrachlorobiphenyls) were enriched in sediment samples accounting for 70-80% of total PCBs. The ranges of DDTs, HCHs, and PCBs in tilapia muscle collected from Fo Tan and Tai Wai were 28.2-40.1 ng/g (DW), 2.04-3.76 ng/g (DW) and 267-310 ng/g (DW), respectively. These values were also significantly higher (p < 0.05) than those collected from the fish ponds. Higher chlorinated PCBs (tetra-, penta-, hexa-, and heptachlorobiphenyls) were commonly found in tilapia accounting for almost 60% of the total PCBs. The effect of lipid contents in organochlorines accumulation was not significant (p < 0.05) in general.