Beef tallow is a byproduct of the slaughter industry. As a consequence, meat producer countries obtain a high amount of this low value-added fatty material. In Uruguay, it is generally used for food purposes or for bi...Beef tallow is a byproduct of the slaughter industry. As a consequence, meat producer countries obtain a high amount of this low value-added fatty material. In Uruguay, it is generally used for food purposes or for biodiesel production. Globally, around half of the beef tallow produced worldwide is used for the manufacturing of food. To the best of our knowledge there are no published studies concerning the stability of beef tallow when exposed to high temperatures. The aim of this work was to study some Uruguayan beef tallow brands and compare its stability with that of the most frequently used frying oils in Uruguay （sunflower high oleic, rice bran and sunflower oil） to assess its suitability for frying. Stability was assessed by the oxidative stability index and thermoxidation in absence of food. Even though beef tallow＇s inherent stability indicated that it should be highly stable to oxidation, the majority of the analyzed samples exhibited a similar or lower stability than sunflower high oleic. This might be explained by a different composition in pro-oxidants and/or antioxidants between the beef tallows and the oils. According to the thermoxidation assays, which are carried out in similar conditions to those of a frying process, three of the beef tallow samples, sunflower high oleic and rice bran oil would be similarly suitable for frying, while sunflower oil and the other two samples of beef tallow evidenced a lower thermoxidative stability, thus not being recommended for this use.展开更多
The effect of microwave （MW） heating on the dielectric properties and oxidation processes of virgin olive oil and refined sunflower oil were determined by dielectric and UV- spectroscopy. Samples were heated in the ...The effect of microwave （MW） heating on the dielectric properties and oxidation processes of virgin olive oil and refined sunflower oil were determined by dielectric and UV- spectroscopy. Samples were heated in the microwave oven （850 W, 2.450 MHz） for 0 to 14 minutes. The results show degradation of dielectric characteristics, conductivity and oxidative stability of investigated oils, increasing with the exposure time. UV spectrum shows only one defined peak at 206 nm for olive oil confirming the dominant presence of monounsaturated fats and four peaks for sunflower oil （203 nm, 230 nm, 269 nm and 278 nm） dependent on polyunsaturated acid fats contents. Increasing of absorbance at all peak wave lengths indicates production of lipid oxidation, due to formation of conjugated monoenes and dienes and in small amounts due to trienes and secondary products like ketoaldehydes. Dielectric constant for olive oil is stable and almost unchangeable with MW radiation while sunflower oil＇s c＇ oscillates around the origin value in greater rate. Dielectric loss e＂ decreases with increasing time of MW radiation and its maximum shifts towards higher frequencies for sunflower oil indicating shortening of the relaxation times, while for olive oil it is unchanged. Cole-Cole analysis show the presence of only one relaxation process in the oils. Conductivity of oils is increasing in similar way with increasing frequency following the Jonscher＇s power law and is not changed with MW exposure time. Olive oil has conductivity higher for four orders of magnitude than sunflower oil, which is connected to the high content of monounsaturated fats. The differences between sunflower and olive oil characteristics are discussed.展开更多
Salvianolic acid B(Sal B)is a polyphenolic antioxidant that has been shown to have anti-lipid accumulation,anti-inflammatory,and free oxygen radical scavenging activities in various diseases.Here,we aimed to examine w...Salvianolic acid B(Sal B)is a polyphenolic antioxidant that has been shown to have anti-lipid accumulation,anti-inflammatory,and free oxygen radical scavenging activities in various diseases.Here,we aimed to examine whether Sal B could alleviate non-alcoholic fatty liver disease(NAFLD)and explore the possible mechanisms.Signaling pathways involved in oxidative stress,including SIRT3,SOD2,and FOXO1 pathways,were investigated by Western blotting analysis,RT-qPCR,and immunoprecipitation(IP).In the present study,oleic acid(OA)successfully induced lipid and peroxide accumulation,decreased SIRT3 expression,and increased FOXO1 acetylation.However,Sal B significantly reversed these trends.SIRT3 plasmid transfection further reduced the expression of acetylated FOXO1 and considerably enhanced the regulation of SIRT3 and acetylated FOXO1 induced by Sal B.Following SIRT3 siRNA transfection,Sal B-induced down-regulation of acetylated FOXO1 was blocked,suggesting that Sal B-mediated protection occurred through SIRT3-mediated FOXO1 deacetylation.The SIRT3/FOXO1 pathway was a critical therapeutic target for controlling oxidative stress in NAFLD,and Sal B conferred protection against OA-induced hepatic steatosis and oxidative stress through SIRT3-mediated FOXO1 deacetylation.展开更多
文摘Beef tallow is a byproduct of the slaughter industry. As a consequence, meat producer countries obtain a high amount of this low value-added fatty material. In Uruguay, it is generally used for food purposes or for biodiesel production. Globally, around half of the beef tallow produced worldwide is used for the manufacturing of food. To the best of our knowledge there are no published studies concerning the stability of beef tallow when exposed to high temperatures. The aim of this work was to study some Uruguayan beef tallow brands and compare its stability with that of the most frequently used frying oils in Uruguay （sunflower high oleic, rice bran and sunflower oil） to assess its suitability for frying. Stability was assessed by the oxidative stability index and thermoxidation in absence of food. Even though beef tallow＇s inherent stability indicated that it should be highly stable to oxidation, the majority of the analyzed samples exhibited a similar or lower stability than sunflower high oleic. This might be explained by a different composition in pro-oxidants and/or antioxidants between the beef tallows and the oils. According to the thermoxidation assays, which are carried out in similar conditions to those of a frying process, three of the beef tallow samples, sunflower high oleic and rice bran oil would be similarly suitable for frying, while sunflower oil and the other two samples of beef tallow evidenced a lower thermoxidative stability, thus not being recommended for this use.
文摘The effect of microwave （MW） heating on the dielectric properties and oxidation processes of virgin olive oil and refined sunflower oil were determined by dielectric and UV- spectroscopy. Samples were heated in the microwave oven （850 W, 2.450 MHz） for 0 to 14 minutes. The results show degradation of dielectric characteristics, conductivity and oxidative stability of investigated oils, increasing with the exposure time. UV spectrum shows only one defined peak at 206 nm for olive oil confirming the dominant presence of monounsaturated fats and four peaks for sunflower oil （203 nm, 230 nm, 269 nm and 278 nm） dependent on polyunsaturated acid fats contents. Increasing of absorbance at all peak wave lengths indicates production of lipid oxidation, due to formation of conjugated monoenes and dienes and in small amounts due to trienes and secondary products like ketoaldehydes. Dielectric constant for olive oil is stable and almost unchangeable with MW radiation while sunflower oil＇s c＇ oscillates around the origin value in greater rate. Dielectric loss e＂ decreases with increasing time of MW radiation and its maximum shifts towards higher frequencies for sunflower oil indicating shortening of the relaxation times, while for olive oil it is unchanged. Cole-Cole analysis show the presence of only one relaxation process in the oils. Conductivity of oils is increasing in similar way with increasing frequency following the Jonscher＇s power law and is not changed with MW exposure time. Olive oil has conductivity higher for four orders of magnitude than sunflower oil, which is connected to the high content of monounsaturated fats. The differences between sunflower and olive oil characteristics are discussed.
基金supported by grants from Wuhan Municipal Health and Family Planning Commission scientific research project(Grant No.WZ20Z04).
文摘Salvianolic acid B(Sal B)is a polyphenolic antioxidant that has been shown to have anti-lipid accumulation,anti-inflammatory,and free oxygen radical scavenging activities in various diseases.Here,we aimed to examine whether Sal B could alleviate non-alcoholic fatty liver disease(NAFLD)and explore the possible mechanisms.Signaling pathways involved in oxidative stress,including SIRT3,SOD2,and FOXO1 pathways,were investigated by Western blotting analysis,RT-qPCR,and immunoprecipitation(IP).In the present study,oleic acid(OA)successfully induced lipid and peroxide accumulation,decreased SIRT3 expression,and increased FOXO1 acetylation.However,Sal B significantly reversed these trends.SIRT3 plasmid transfection further reduced the expression of acetylated FOXO1 and considerably enhanced the regulation of SIRT3 and acetylated FOXO1 induced by Sal B.Following SIRT3 siRNA transfection,Sal B-induced down-regulation of acetylated FOXO1 was blocked,suggesting that Sal B-mediated protection occurred through SIRT3-mediated FOXO1 deacetylation.The SIRT3/FOXO1 pathway was a critical therapeutic target for controlling oxidative stress in NAFLD,and Sal B conferred protection against OA-induced hepatic steatosis and oxidative stress through SIRT3-mediated FOXO1 deacetylation.
