The consumption of high-fat hamburger enriched with saturated fatty acids (SFA) and trans-fatty acids (TFA) may increase risk factors for cardiovascular disease, whereas hamburger enriched with monounsaturated fatty acids (MUFA) may have the opposite effect. Ten mildly hypercholesterolemic men consumed five, 114-g hamburger patties per week for two consecutive phases. Participants consumed low-MUFA (high SFA) hamburger (MUFA:SFA = 0.95; produced from pasture-fed cattle) for 5 wk, consumed their habitual diets for 3 wk, and then consumed high-MUFA hamburger (MUFA:SFA = 1.31; produced from grain-fed cattle) for 5 wk. These MUFA:SFA were typical of ranges observed for retail ground beef. Relative to habitual levels and levels during the high-MUFA phase, the low-MUFA hamburger: increased plasma palmitic acid, palmitoleic acid, and triacylglycerols (P < 0.01); decreased HDL cholesterol (HDL-C) and LDL particle diameter percentile distributions (P < 0.05); and had no effect on LDL-C or plasma glucose (P > 0.10). Plasma palmitoleic acid was positively correlated with triacylglycerols (r = 0.90), VLDL-C (r = 0.73), and the LDL:HDL (r = 0.45), and was negatively correlated with plasma HDL-C (r = -0.58), whereas plasma palmitic, stearic, and oleic acid were negatively correlated with LDL particle diameter (all P <= 0.05). Because plasma palmitoleic acid was derived from [delta]9 desaturation of palmitic acid in the liver, we conclude that alterations in hepatic stearoyl-CoA desaturase activity may have been responsible for the variation in HDL-C and triacylglycerols caused by the low-MUFA and high-MUFA hamburgers. Cattle with a genetic predisposition to deposit MUFA in their lean and fat tissues, such as Wagyu cattle can be used to produce beef products that are especially enriched with oleic acid and lower in SFA and TFA, and feeding practices can further enhance the composition of beef fat. This indicates that ground beef or hamburger products can be produced that are naturally enriched with oleic acid, and conversely that certain production practices can impair the nutritional quality of beef fat. Finally, we cannot discern from this study design whether the high-MUFA hamburger reversed the effects of the low-MUFA hamburger, or whether the subjects gradually adapted to the elevated intake of total fat. It is clear, however, that the high-MUFA hamburger did not exacerbate any of the effects of the low-MUFA hamburger and can be viewed as at least neutral in its effects on HDL-C and triacylglycerols.

Thesis (Ph. D.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains ix, 86 p. : ill. (some col.). Includes abstract. Includes bibliographical references.

Thesis (M.S.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains iv, 60 p. : ill. (some col.). Includes abstract. Includes bibliographical references.

Investigating the biosynthesis of long-chain (C20–24) polyunsaturated fatty acids (LC-PUFA), physiologically important compounds including arachidonic acid (ARA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in fish is crucial to identify dietary requirements for essential fatty acids (EFA). Moreover, knowledge of the C20–24 LC-PUFA biosynthetic capability of farmed fish species enables us to understand their ability to utilise commonly used raw materials such as vegetable oils, which naturally lack LC-PUFA but include C18 PUFA that are metabolic precursors of LC-PUFA. Studies have shown that the potential of a species for LC-PUFA biosynthesis is associated with the complement and function of fatty acyl desaturase (fads) and elongase of very long chain fatty acid (elovl) genes existing in that species. The present study therefore aimed to investigate these genes in the African catfish (Clarias gariepinus), the most commercially important farmed fish in sub-Saharan Africa. A fads2, a fads6 and four elovl (elovl2, elovl4a, elovl4b, elovl8) cDNAs were cloned and functionally characterised by heterologous expression in yeast. The Fads2 was a bifunctional desaturase enzyme with ∆6∆5 and ∆8 activities, and thus catalysing all the desaturation reactions required for ARA and EPA biosynthesis from C18 precursor fatty acids. Moreover, the C. gariepinus Fads2 enzymes also desaturated 24:5n-3 to 24:6n-3, a ∆6 desaturation required for the biosynthesis of DHA through the so-called “Sprecher pathway”. Functional characterisation of Fads6 by heterologous expression in yeast did not reveal its function. With regards to elongases, the C. gariepinus Elovl2 demonstrated the ability to elongate C20 and C22 PUFA and thus complements the Elovl5 with elongase capability towards C18 and C20 PUFA. The Elovl8 was capable of only limited elongation of C18 and C20 PUFA. Elovl4a and Elovl4b, enable the biosynthesis of very long-chain (>C24) fatty acids, compounds with major roles in vision and fertility of vertebrates. The present study confirmed that C. gariepinus possess all the enzymatic capabilities required for the biosynthesis of ARA, EPA and DHA and, therefore, its physiological EFA requirements could be satisfied with dietary provision of C18 PUFA.

nÃo hà / Os Ãsteres de Ãcidos graxos representam uma das mais importantes classes de compostos orgÃnicos devido à diversidade de aplicaÃÃes, tais como aromas, biopesticida, biodiesel e antimicrobianos. O setor industrial de Ãleos e gorduras, bem como as pesquisas cientÃficas, tem desenvolvido diversos processos para manipular a composiÃÃo das misturas de triglicerÃdeos para a sÃntese de Ãsteres a partir dos Ãcidos graxos, por rota quÃmica ou enzimÃtica. Nesse contexto, a lipase à a enzima mais amplamente utilizada por apresentar diversas vantagens relacionadas à sua especificidade. Assim, o objetivo deste estudo foi avaliar a seletividade das lipases imobilizadas de Candida antarctica tipo B e de Rhizopus oryzae em relaÃÃo aos Ãcidos graxos saturados (AGS) e insaturados (AGI), bem como a conversÃo destes em Ãsteres etÃlicos. A seletividade foi avaliada em relaÃÃo ao Ãcido oleico (insaturado) e o Ãcido eicosanÃico (saturado), obtidos na hidrÃlise quÃmica do Ãleo do peixe tilÃpia (Oreochromis niloticus). Para anÃlise da seletividade foi realizado um planejamento experimental composto central 24, variando a velocidade de agitaÃÃo (rpm), temperatura (ÂC), razÃo molar (etanol:Ãcido graxo) e quantidade de enzima (%m), mantendo-se fixa a quantidade de peneira molecular â zeÃlita 5 à â (5 %m) e o tempo reacional (24 h). Da mesma forma, o comportamento das enzimas em relaÃÃo aos AGS foi avaliado segundo planejamento experimental composto central 23, variando temperatura (ÂC), razÃo molar (etanol:Ãcido graxo) e quantidade de enzima (%m), mantendo-se fixa a quantidade de peneira â zeÃlita 5 à â molecular (5 %m), agitaÃÃo (180 rpm) e tempo reacional (24 h), utilizando como substrato uma mistura de Ãcidos palmÃtico e esteÃrico. Em todas as anÃlises estatÃsticas foram considerados 85% de intervalo de confianÃa. Em relaÃÃo à esterificaÃÃo dos Ãcidos graxos do Ãleo de peixe hidrolisado, ambos os catalisadores foram seletivos para o Ãcido saturado eicosanÃico. Quase todas as variÃveis estudadas influenciaram na seletividade da lipase de R. oryzae, enquanto quase nenhuma foi significativa para a seletividade da lipase de C. antarctica. Quando a resposta estudada foi a conversÃo, a lipase de C. antarctica foi responsÃvel pelas maiores conversÃes de Ãcido oleico em oleato de etila. Quando os ensaios foram realizados utilizando lipase de R. oryzae, mais variÃveis significativas foram encontradas para o modelo de conversÃo. No meio reacional contendo a mistura de AGS, ambas as lipases apresentaram maior afinidade pelo Ãcido palmÃtico. A faixa de valores selecionada para avaliar a influÃncia na seletividade nÃo afetou significativamente a resposta da lipase de C. antarctica, mas foram todas significativas para a de R. oryzae. Quanto à conversÃo, a lipase de C. antarctica foi responsÃvel pelas maiores conversÃes de Ãcidos esteÃrico e praticamente todas as variÃveis selecionadas foram significativas para o modelo da conversÃo quando ambas as enzimas foram utilizadas. / Esters of fatty acids represent one of the most important classes of organic compounds due to ther variety of applications, such as flavoring, biopesticide, biodiesel and antimicrobials. Oils and fats industry as well as scientific researches have developed many different processes to manipulate composition of triglycerides mixtures. The aim is synthesis of esters from fatty acids by chemical or enzymatic routes. In this context, lipase is the most widely used enzyme due to several advantages related its specificity. The aim of this study was to evaluate the selectivity of immobilized lipases of Candida antarctica type B and Rhizopus oryzae compared to saturated (SFA) and unsaturated (UFA) fatty acids as well as their yield into ethyl esters. Selectivity was assessed with respect to oleic acid (unsaturated) and eicosanoic acid (saturated), obtained from chemical hydrolysis of fish oil Tilapia (Oreochromis niloticus), through 24 central composite design using agitation rate (rpm), temperature (ÂC), molar ratio (ethanol:fatty acid) and amount of enzyme (%wt) as independ variables (design factors). The amount of molecular sieve â zeolite 5 à â (5 %wt) and reaction time (24 h) were fixed. Likewise, the behavior of both enzymes to the SFA was evaluated according to 23 central composite design where temperature (ÂC), molar ratio (ethanol:fatty acid) and amount of enzyme (%wt) were independ variables. The amount of molecular sieve â zeolite 5 à â (5 %wt), stirring (180 rpm) and reaction time (24 h) were fixed and a mixture of palmitic and stearic acids was used as substrate. A confidence interval of 85% was considered for all statistical analyses. Regarding the esterification of fatty acids from hydrolyzed fish oil, both catalysts were selective for saturated eicosanoic acid rather than for the unsaturated acid. The design factors did not present significant effect on response variable when lipase from C. antarctica was used like catalyst. However all design factors presented an influence on the selectivity when lipase from R. oryzae was used like catalyst. In this way, lipase of C. antarctica lead to higher conversions of oleic acid into ethyl oleate and more significant variables have been found for the model when lipase of R. oryzae was uesd in assays. In the reaction medium containing the mixture of SFA, both lipases showed higher affinity for palmitic acid. The values range selected to evaluate the selectivity did not present significant effect on responses when lipase from C. antarctica was used, however that value range was significant for all assays performed using lipase from R. oryzae. The higher stearic acid conversions were obtained when lipase from C. antarctica was used like catalyst and all design factors were significant for both enzymes.

Indiana University-Purdue University Indianapolis (IUPUI) / Omega-3 polyunsaturated fatty acids (n-3 PUFAs) relieve the symptoms of a wide variety of chronic inflammatory disorders. Typically, they must be obtained in the diet from sources such as fish oils. Docosahexaenoic acid (DHA) is one of these n-3 PUFAs. As yet the structural mechanism responsible for the health benefits within the body is not completely understood. One model that has emerged from biochemical and imaging studies of cells suggests that n-3 PUFAs are taken up into phospholipids in the plasma membrane. Thus the focus here is on the plasma membrane as a site of potential structural modification by DHA. Within cellular membranes, the huge variety of molecules (called lipids) which constitute the membrane suggest inhomogeneous mixing, thus domain formation. One potential domain of interest is called the lipid raft, which is primarily composed of sphingomyelin (SM) and cholesterol (chol). Here the molecular organization of [2H31]-N-palmitoylsphingomyelin (PSM-d31) mixed with 1-palmitoyl-2-docosahexaenoylphosphatylcholine (PDPC) or 1-palmitoyl-2-oleoylphosphatidylcholine (POPC), as a monounsaturated control, and cholesterol (chol) (1:1:1 mol) in a model membrane was examined by solid state 2H NMR spectroscopy. Solid state 2H NMR spectroscopy extracts details of molecular orientation and anisotropy of molecular reorientation by analysis of the lineshape. This essentially non-invasive technique allows for a direct measurement of dynamics in bulk materials which has been extensively applied to biological materials. It is a niche area of NMR for which standard software often lack necessary features. Two software programs, “EchoNMR processor” and “EchoNMR simulator”, collectively known as “EchoNMR tools”, that were developed to quickly process and analyze one-dimensional solid-state NMR data, will be described along with some theoretical background of the techniques used. EchoNMR tools has been designed with a focus on usability and the open-source mindset. This is achieved in the in the MATLAB® programming environment which allows for the development of the graphical user interfaces and runs as an interpreter which allows the code to be open-source. The research described here on model membranes demonstrates the utility of the software. The NMR spectra for PSM-d31 in mixtures with PDPC or POPC with cholesterol were interpreted in terms of the presence of nano-sized SM-rich/chol-rich (raft-like) and PC-rich/chol-poor (non-raft) domains that become larger when POPC was replaced by PDPC. An increase in the differential in order and/or thickness between the two types of domains is responsible. The observation of separate signals from PSM-d31, and correspondingly from [3α-2H1]cholesterol (chol-d1) and 1-[2H31]palmitoyl-2-docosahexaenoylphosphatidylcholine (PDPC-d31), attributed to the raft-like and non-raft domains enabled the determination of the composition of the domains. Most of the SM (84%) and cholesterol (88%) was found in the raft-like domain. There was also a substantial amount of PDPC (70%) in the raft-like domain that appears to have minimal effect on the order of SM. PDPC molecules sequestering into small groups to minimize the contact of DHA chains with cholesterol is one possible explanation that would also have implications on raft continuity. These results refine the understanding of how DHA may modulate the structure of raft domains in membranes.

No description available.

Tyrophagus putrescentiae, (ham mite) is difficult for commercial dry cured ham producers to control. This research was conducted to test the efficacy of C8C9C10 fatty acids combined with and without food grade coatings to control mite infestations on dry cured hams. Ham cubes were coated directly or wrapped in nets saturated with combinations of xanthan gum (XG) or carrageenan (CG), propylene glycol alginate (PGA), and either propylene glycol or C8C9C10 fatty acid. The use of 10% C8C9C10 with XG and CG + PGA in direct coatings and 1% C8C9C10 with XG or 10% with both XG and CG/PGA in saturated nets inhibited mite population growth. Unexpectedly, the soybean oil solvent effectively controlled mite infestation. Sensory evaluation indicated that 10% C8C9C10 mixed with soybean oil and 100% soybean oil did not impart sensory differences to ham when used as a coating but did impact sensory attributes when used with nets.

No description available.

No description available.