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Contributors
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- By Mitchell Aboulafia, Frederick Adams, Marilyn McCord Adams, Robert M. Adams, Laird Addis, James W. Allard, David Allison, William P. Alston, Karl Ameriks, C. Anthony Anderson, David Leech Anderson, Lanier Anderson, Roger Ariew, David Armstrong, Denis G. Arnold, E. J. Ashworth, Margaret Atherton, Robin Attfield, Bruce Aune, Edward Wilson Averill, Jody Azzouni, Kent Bach, Andrew Bailey, Lynne Rudder Baker, Thomas R. Baldwin, Jon Barwise, George Bealer, William Bechtel, Lawrence C. Becker, Mark A. Bedau, Ernst Behler, José A. Benardete, Ermanno Bencivenga, Jan Berg, Michael Bergmann, Robert L. Bernasconi, Sven Bernecker, Bernard Berofsky, Rod Bertolet, Charles J. Beyer, Christian Beyer, Joseph Bien, Joseph Bien, Peg Birmingham, Ivan Boh, James Bohman, Daniel Bonevac, Laurence BonJour, William J. Bouwsma, Raymond D. Bradley, Myles Brand, Richard B. Brandt, Michael E. Bratman, Stephen E. Braude, Daniel Breazeale, Angela Breitenbach, Jason Bridges, David O. Brink, Gordon G. Brittan, Justin Broackes, Dan W. Brock, Aaron Bronfman, Jeffrey E. Brower, Bartosz Brozek, Anthony Brueckner, Jeffrey Bub, Lara Buchak, Otavio Bueno, Ann E. Bumpus, Robert W. Burch, John Burgess, Arthur W. Burks, Panayot Butchvarov, Robert E. Butts, Marina Bykova, Patrick Byrne, David Carr, Noël Carroll, Edward S. Casey, Victor Caston, Victor Caston, Albert Casullo, Robert L. Causey, Alan K. L. Chan, Ruth Chang, Deen K. Chatterjee, Andrew Chignell, Roderick M. Chisholm, Kelly J. Clark, E. J. Coffman, Robin Collins, Brian P. Copenhaver, John Corcoran, John Cottingham, Roger Crisp, Frederick J. Crosson, Antonio S. Cua, Phillip D. Cummins, Martin Curd, Adam Cureton, Andrew Cutrofello, Stephen Darwall, Paul Sheldon Davies, Wayne A. Davis, Timothy Joseph Day, Claudio de Almeida, Mario De Caro, Mario De Caro, John Deigh, C. F. Delaney, Daniel C. Dennett, Michael R. DePaul, Michael Detlefsen, Daniel Trent Devereux, Philip E. Devine, John M. Dillon, Martin C. Dillon, Robert DiSalle, Mary Domski, Alan Donagan, Paul Draper, Fred Dretske, Mircea Dumitru, Wilhelm Dupré, Gerald Dworkin, John Earman, Ellery Eells, Catherine Z. Elgin, Berent Enç, Ronald P. Endicott, Edward Erwin, John Etchemendy, C. Stephen Evans, Susan L. Feagin, Solomon Feferman, Richard Feldman, Arthur Fine, Maurice A. Finocchiaro, William FitzPatrick, Richard E. Flathman, Gvozden Flego, Richard Foley, Graeme Forbes, Rainer Forst, Malcolm R. Forster, Daniel Fouke, Patrick Francken, Samuel Freeman, Elizabeth Fricker, Miranda Fricker, Michael Friedman, Michael Fuerstein, Richard A. Fumerton, Alan Gabbey, Pieranna Garavaso, Daniel Garber, Jorge L. A. Garcia, Robert K. Garcia, Don Garrett, Philip Gasper, Gerald Gaus, Berys Gaut, Bernard Gert, Roger F. Gibson, Cody Gilmore, Carl Ginet, Alan H. Goldman, Alvin I. Goldman, Alfonso Gömez-Lobo, Lenn E. Goodman, Robert M. Gordon, Stefan Gosepath, Jorge J. E. Gracia, Daniel W. Graham, George A. Graham, Peter J. Graham, Richard E. Grandy, I. Grattan-Guinness, John Greco, Philip T. Grier, Nicholas Griffin, Nicholas Griffin, David A. Griffiths, Paul J. Griffiths, Stephen R. Grimm, Charles L. Griswold, Charles B. Guignon, Pete A. Y. Gunter, Dimitri Gutas, Gary Gutting, Paul Guyer, Kwame Gyekye, Oscar A. Haac, Raul Hakli, Raul Hakli, Michael Hallett, Edward C. Halper, Jean Hampton, R. James Hankinson, K. R. Hanley, Russell Hardin, Robert M. Harnish, William Harper, David Harrah, Kevin Hart, Ali Hasan, William Hasker, John Haugeland, Roger Hausheer, William Heald, Peter Heath, Richard Heck, John F. Heil, Vincent F. Hendricks, Stephen Hetherington, Francis Heylighen, Kathleen Marie Higgins, Risto Hilpinen, Harold T. Hodes, Joshua Hoffman, Alan Holland, Robert L. Holmes, Richard Holton, Brad W. Hooker, Terence E. Horgan, Tamara Horowitz, Paul Horwich, Vittorio Hösle, Paul Hoβfeld, Daniel Howard-Snyder, Frances Howard-Snyder, Anne Hudson, Deal W. Hudson, Carl A. Huffman, David L. Hull, Patricia Huntington, Thomas Hurka, Paul Hurley, Rosalind Hursthouse, Guillermo Hurtado, Ronald E. Hustwit, Sarah Hutton, Jonathan Jenkins Ichikawa, Harry A. Ide, David Ingram, Philip J. Ivanhoe, Alfred L. Ivry, Frank Jackson, Dale Jacquette, Joseph Jedwab, Richard Jeffrey, David Alan Johnson, Edward Johnson, Mark D. Jordan, Richard Joyce, Hwa Yol Jung, Robert Hillary Kane, Tomis Kapitan, Jacquelyn Ann K. Kegley, James A. Keller, Ralph Kennedy, Sergei Khoruzhii, Jaegwon Kim, Yersu Kim, Nathan L. King, Patricia Kitcher, Peter D. Klein, E. D. Klemke, Virginia Klenk, George L. Kline, Christian Klotz, Simo Knuuttila, Joseph J. Kockelmans, Konstantin Kolenda, Sebastian Tomasz Kołodziejczyk, Isaac Kramnick, Richard Kraut, Fred Kroon, Manfred Kuehn, Steven T. Kuhn, Henry E. Kyburg, John Lachs, Jennifer Lackey, Stephen E. Lahey, Andrea Lavazza, Thomas H. Leahey, Joo Heung Lee, Keith Lehrer, Dorothy Leland, Noah M. Lemos, Ernest LePore, Sarah-Jane Leslie, Isaac Levi, Andrew Levine, Alan E. Lewis, Daniel E. Little, Shu-hsien Liu, Shu-hsien Liu, Alan K. L. Chan, Brian Loar, Lawrence B. Lombard, John Longeway, Dominic McIver Lopes, Michael J. Loux, E. J. Lowe, Steven Luper, Eugene C. Luschei, William G. Lycan, David Lyons, David Macarthur, Danielle Macbeth, Scott MacDonald, Jacob L. Mackey, Louis H. Mackey, Penelope Mackie, Edward H. Madden, Penelope Maddy, G. B. Madison, Bernd Magnus, Pekka Mäkelä, Rudolf A. Makkreel, David Manley, William E. Mann (W.E.M.), Vladimir Marchenkov, Peter Markie, Jean-Pierre Marquis, Ausonio Marras, Mike W. Martin, A. P. Martinich, William L. McBride, David McCabe, Storrs McCall, Hugh J. McCann, Robert N. McCauley, John J. McDermott, Sarah McGrath, Ralph McInerny, Daniel J. McKaughan, Thomas McKay, Michael McKinsey, Brian P. McLaughlin, Ernan McMullin, Anthonie Meijers, Jack W. Meiland, William Jason Melanson, Alfred R. Mele, Joseph R. Mendola, Christopher Menzel, Michael J. Meyer, Christian B. Miller, David W. Miller, Peter Millican, Robert N. Minor, Phillip Mitsis, James A. Montmarquet, Michael S. Moore, Tim Moore, Benjamin Morison, Donald R. Morrison, Stephen J. Morse, Paul K. Moser, Alexander P. D. Mourelatos, Ian Mueller, James Bernard Murphy, Mark C. Murphy, Steven Nadler, Jan Narveson, Alan Nelson, Jerome Neu, Samuel Newlands, Kai Nielsen, Ilkka Niiniluoto, Carlos G. Noreña, Calvin G. Normore, David Fate Norton, Nikolaj Nottelmann, Donald Nute, David S. Oderberg, Steve Odin, Michael O’Rourke, Willard G. Oxtoby, Heinz Paetzold, George S. Pappas, Anthony J. Parel, Lydia Patton, R. P. Peerenboom, Francis Jeffry Pelletier, Adriaan T. Peperzak, Derk Pereboom, Jaroslav Peregrin, Glen Pettigrove, Philip Pettit, Edmund L. Pincoffs, Andrew Pinsent, Robert B. Pippin, Alvin Plantinga, Louis P. Pojman, Richard H. Popkin, John F. Post, Carl J. Posy, William J. Prior, Richard Purtill, Michael Quante, Philip L. Quinn, Philip L. Quinn, Elizabeth S. Radcliffe, Diana Raffman, Gerard Raulet, Stephen L. Read, Andrews Reath, Andrew Reisner, Nicholas Rescher, Henry S. Richardson, Robert C. Richardson, Thomas Ricketts, Wayne D. Riggs, Mark Roberts, Robert C. Roberts, Luke Robinson, Alexander Rosenberg, Gary Rosenkranz, Bernice Glatzer Rosenthal, Adina L. Roskies, William L. Rowe, T. M. Rudavsky, Michael Ruse, Bruce Russell, Lilly-Marlene Russow, Dan Ryder, R. M. Sainsbury, Joseph Salerno, Nathan Salmon, Wesley C. Salmon, Constantine Sandis, David H. Sanford, Marco Santambrogio, David Sapire, Ruth A. Saunders, Geoffrey Sayre-McCord, Charles Sayward, James P. Scanlan, Richard Schacht, Tamar Schapiro, Frederick F. Schmitt, Jerome B. Schneewind, Calvin O. Schrag, Alan D. Schrift, George F. Schumm, Jean-Loup Seban, David N. Sedley, Kenneth Seeskin, Krister Segerberg, Charlene Haddock Seigfried, Dennis M. Senchuk, James F. Sennett, William Lad Sessions, Stewart Shapiro, Tommie Shelby, Donald W. Sherburne, Christopher Shields, Roger A. Shiner, Sydney Shoemaker, Robert K. Shope, Kwong-loi Shun, Wilfried Sieg, A. John Simmons, Robert L. Simon, Marcus G. Singer, Georgette Sinkler, Walter Sinnott-Armstrong, Matti T. Sintonen, Lawrence Sklar, Brian Skyrms, Robert C. Sleigh, Michael Anthony Slote, Hans Sluga, Barry Smith, Michael Smith, Robin Smith, Robert Sokolowski, Robert C. Solomon, Marta Soniewicka, Philip Soper, Ernest Sosa, Nicholas Southwood, Paul Vincent Spade, T. L. S. Sprigge, Eric O. Springsted, George J. Stack, Rebecca Stangl, Jason Stanley, Florian Steinberger, Sören Stenlund, Christopher Stephens, James P. Sterba, Josef Stern, Matthias Steup, M. A. Stewart, Leopold Stubenberg, Edith Dudley Sulla, Frederick Suppe, Jere Paul Surber, David George Sussman, Sigrún Svavarsdóttir, Zeno G. Swijtink, Richard Swinburne, Charles C. Taliaferro, Robert B. Talisse, John Tasioulas, Paul Teller, Larry S. Temkin, Mark Textor, H. S. Thayer, Peter Thielke, Alan Thomas, Amie L. Thomasson, Katherine Thomson-Jones, Joshua C. Thurow, Vzalerie Tiberius, Terrence N. Tice, Paul Tidman, Mark C. Timmons, William Tolhurst, James E. Tomberlin, Rosemarie Tong, Lawrence Torcello, Kelly Trogdon, J. D. Trout, Robert E. Tully, Raimo Tuomela, John Turri, Martin M. Tweedale, Thomas Uebel, Jennifer Uleman, James Van Cleve, Harry van der Linden, Peter van Inwagen, Bryan W. Van Norden, René van Woudenberg, Donald Phillip Verene, Samantha Vice, Thomas Vinci, Donald Wayne Viney, Barbara Von Eckardt, Peter B. M. Vranas, Steven J. Wagner, William J. Wainwright, Paul E. Walker, Robert E. Wall, Craig Walton, Douglas Walton, Eric Watkins, Richard A. Watson, Michael V. Wedin, Rudolph H. Weingartner, Paul Weirich, Paul J. Weithman, Carl Wellman, Howard Wettstein, Samuel C. Wheeler, Stephen A. White, Jennifer Whiting, Edward R. Wierenga, Michael Williams, Fred Wilson, W. Kent Wilson, Kenneth P. Winkler, John F. Wippel, Jan Woleński, Allan B. Wolter, Nicholas P. Wolterstorff, Rega Wood, W. Jay Wood, Paul Woodruff, Alison Wylie, Gideon Yaffe, Takashi Yagisawa, Yutaka Yamamoto, Keith E. Yandell, Xiaomei Yang, Dean Zimmerman, Günter Zoller, Catherine Zuckert, Michael Zuckert, Jack A. Zupko (J.A.Z.)
- Edited by Robert Audi, University of Notre Dame, Indiana
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- The Cambridge Dictionary of Philosophy
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- 05 August 2015
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- 27 April 2015, pp ix-xxx
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Effect of grazing fresh legumes or feeding silage on fatty acids and enzymes involved in the synthesis of milk fat in dairy cows
- Lars Wiking, Peter K Theil, Jacob H Nielsen, Martin T Sørensen
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- Journal:
- Journal of Dairy Research / Volume 77 / Issue 3 / August 2010
- Published online by Cambridge University Press:
- 10 May 2010, pp. 337-342
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- August 2010
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The impact of fresh legume types or silage on the composition of milk fatty acids and transcription of enzymes involved in the synthesis of milk fat in cows was studied. Three groups of cows grazed high proportions of white clover, red clover and lucerne, respectively. A fourth group of cows was fed maize/grass silage. The cows grazing high proportions of legumes produced significantly more 18:1 trans-11, 18:2 cis9-trans11, 18:2 trans10-cis12 and 18:3 fatty acids than cows fed silage. White clover and lucerne grazing resulted in significantly lower output of 18:1 trans9 in milk than red clover grazing and maize/grass silages. Transcription of stearoyl-CoA desaturase (SCD) in mammary tissue was significantly increased by grazing high proportions of legume whereas fatty acid synthase and acetyl-CoA carboxylase were not affected by type of feeding. Furthermore, average milk fat globule diameter was correlated to daily milk fat yield but was not affected by feeding. Although the fresh forage affected the transcription of SCD in mammary tissue, the largest effects were on the trans11-based fatty acids. It is concluded that type of forage, i.e. fresh or silage, had a greater impact on rumen fermentation pattern than on transcription of enzymes involved in the synthesis of milk fat.
Short-term effects of selenium supplementation of cows' feed on the content and distribution of selenium, copper and zinc in bovine milk, whey and blood plasma
- Tien Hoac, Jan Stagsted, Thomas Lundh, Jacob H Nielsen, Björn Åkesson
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- Journal:
- Journal of Dairy Research / Volume 75 / Issue 3 / August 2008
- Published online by Cambridge University Press:
- 04 August 2008, pp. 326-334
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- August 2008
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The effect of selenium supplementation of feed on the Se content in bovine milk, whey and plasma, and on the distribution of Se, Zn and Cu in whey and plasma was investigated. In a cross-over study two groups of cows were given a basal feed with 0·16 ppm selenite (approx. 3 mg Se/d) with or without 25 mg yeast Se/d for 2 weeks. In the supplemented group the Se content increased 10-fold in milk, 10-fold in whey and 2-fold in plasma, and after the cessation of the supplementation, selenium in milk decreased with a calculated half-life of 3·5 d. In another experiment, two groups of cows were given either 100 mg yeast Se/d for 1 week or only the basal feed. The increase in Se content in both whole and defatted milk was 40–50-fold, and in whey it was approx. 20-fold. Size-exclusion chromatography of whey using inductively coupled plasma mass spectrometry for detection showed that supplementation increased the proportion of Se in the β-lactoglobulin-α-lactalbumin fraction. Distribution of Cu and Zn was essentially unaffected. In plasma, supplementation increased the Se content in all major Se fractions like selenoprotein P, albumin and low-molecular-weight compounds, but the distribution profiles of Zn and Cu underwent no major changes. The study showed for the first time the rapid kinetics of the Se increase and decrease in milk after the initiation and cessation of supplementation, respectively, and the preferential appearance of Se in the β-lactoglobulin-α-lactalbumin fraction of whey. Milk highly enriched in selenium will be a useful tool for different research purposes.
Bulky DNA adducts, 4-aminobiphenyl-haemoglobin adducts and diet in the European Prospective Investigation into Cancer and Nutrition (EPIC) prospective study
- Marco Peluso, Luisa Airoldi, Armelle Munnia, Alessandro Colombi, Fabrizio Veglia, Herman Autrup, Alison Dunning, Seymour Garte, Emmanuelle Gormally, Christian Malaveille, Giuseppe Matullo, Kim Overvad, Ole Raaschou-Nielsen, Francoise Clavel-Chapelon, Jacob Linseisen, Heiner Boeing, Antonia Trichopoulou, Domenico Palli, Vittorio Krogh, Rosario Tumino, Salvatore Panico, Bas H. Bueno-De-Mesquita, Petra H. Peeters, Merethe Kumle, Antonio Agudo, Carmen Martinez, Miren Dorronsoro, Aurelio Barricarte, Marìa Jose Tormo, José Ramón Quiros, Goran Berglund, Bengt Jarvholm, Nicholas E. Day, Timothy J. Key, Rodolfo Saracci, Rudolf Kaaks, Elio Riboli, Shelia Bingham, Paolo Vineis
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- British Journal of Nutrition / Volume 100 / Issue 3 / September 2008
- Published online by Cambridge University Press:
- 14 February 2008, pp. 489-495
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- September 2008
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In contrast to some extensively examined food mutagens, for example, aflatoxins, N-nitrosamines and heterocyclic amines, some other food contaminants, in particular polycyclic aromatic hydrocarbons (PAH) and other aromatic compounds, have received less attention. Therefore, exploring the relationships between dietary habits and the levels of biomarkers related to exposure to aromatic compounds is highly relevant. We have investigated in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort the association between dietary items (food groups and nutrients) and aromatic DNA adducts and 4-aminobiphenyl-Hb adducts. Both types of adducts are biomarkers of carcinogen exposure and possibly of cancer risk, and were measured, respectively, in leucocytes and erythrocytes of 1086 (DNA adducts) and 190 (Hb adducts) non-smokers. An inverse, statistically significant, association has been found between DNA adduct levels and dietary fibre intake (P = 0·02), vitamin E (P = 0·04) and alcohol (P = 0·03) but not with other nutrients or food groups. Also, an inverse association between fibre and fruit intake, and BMI and 4-aminobiphenyl-Hb adducts (P = 0·03, 0·04, and 0·03 respectively) was observed. After multivariate regression analysis these inverse correlations remained statistically significant, except for the correlation adducts v. fruit intake. The present study suggests that fibre intake in the usual range can modify the level of DNA or Hb aromatic adducts, but such role seems to be quantitatively modest. Fibres could reduce the formation of DNA adducts in different manners, by diluting potential food mutagens and carcinogens in the gastrointestinal tract, by speeding their transit through the colon and by binding carcinogenic substances.
Evaluation of cooling strategies for pumping of milk – Impact of fatty acid composition on free fatty acid levels
- Lars Wiking, Hanne C Bertram, Lennart Björck, Jacob H Nielsen
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- Journal:
- Journal of Dairy Research / Volume 72 / Issue 4 / November 2005
- Published online by Cambridge University Press:
- 15 September 2005, pp. 476-481
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- November 2005
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Cooling strategies for pumping of raw milk were evaluated. Milk was pumped for 450 s at 31 °C, or pumped after cooling to 4 °C and subsequently subjected to various incubation times. Two types of milk were used; i.e. milk from cows fed a diet high in saturated fat supplements resulting in significantly larger milk fat globules than the other type of milk which comes from cows fed a low-fat diet that stimulates high de novo fat synthesis. The content of liquid fat was determined by low-field 1H NMR, which showed that milk from cows given the saturated fat diet also contained less liquid fat at both 4 ° and 31 °C than the other type of milk. This can be ascribed to the differences in the fatty acid composition of the milk as a result of the fatty acid composition of the diets. After pumping of the milk at 31 °C, measurement of fat globule size distribution revealed a significant coalescence of milk fat globules in the milk obtained from the saturated fat diet due to pumping. Pumping at 4 °C or pumping the other type of milk did not result in coalescence of milk fat globules. Formation of free fatty acids increased significantly in both types of milk by pumping at 31 °C. Cooling the milk to 4 °C immediately before pumping inhibited an increased content of free fatty acids. However, when the milk was incubated at 4 °C for 60 min after cooling and then subjected to pumping, a significant increase in the formation of free fatty acids was observed in both types of milk. It is suggested that this increase in free fatty acids is caused by transition of polymorphic crystal forms or higher level of attached lipoprotein lipases to the milk fat globule before pumping.
The influence of oxidation on proteolysis in raw milk
- Lars Wiking, Jacob H Nielsen
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- Journal:
- Journal of Dairy Research / Volume 71 / Issue 2 / May 2004
- Published online by Cambridge University Press:
- 04 May 2004, pp. 196-200
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- May 2004
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The link between oxidation and increased proteolysis in raw milk was studied. To accelerate oxidation, H2O2 (1 mM) was added to raw milk, resulting in enhanced proteolysis by up to 11·2% after 24 h incubation at 5 °C. Addition of Cu2+ (10 μM) to milk or exposure of milk to light (60 min) likewise increased proteolysis. To explain the mechanism responsible for increased proteolysis as a result of oxidation, the effect of lipid oxidation products on plasmin-induced proteolysis was tested. Addition of malondialdehyde to skim milk increased the formation of γ-caseins, a proteolysis product from plasmin hydrolysis of β-casein. The same observation was made in a model system containing 4·5 g β-casein/l sodium tetraborate buffer at pH 8 and plasmin. Addition of a plasmin inhibitor blocked the formation of γ-casein. The results indicate that aldehydes accumulated from lipid oxidation can modify β-casein and thereby increase susceptibility of the proteins to proteolysis. Furthermore, the data suggest that proteolysis in raw milk may be connected to oxidative processes.
Oxidative stability of buttermilk as influenced by the fatty acid composition of cows' milk manipulated by diet
- Dorthe Kristensen, Rikke V Hedegaard, Jacob H Nielsen, Leif H Skibsted
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- Journal:
- Journal of Dairy Research / Volume 71 / Issue 1 / February 2004
- Published online by Cambridge University Press:
- 08 March 2004, pp. 46-50
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- February 2004
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Milk from cows fed a low-fat diet high in cereals designed to stimulate fat synthesis de novo was lower in unsaturated fatty acids (21·3%) than milk from cows fed a diet high in fat, mainly from roasted soy beans (41·3% unsaturated fatty acids). Buttermilk from the more unsaturated milk was less oxidatively stable during storage (at 4 °C, followed for 11 d) than buttermilk from the more saturated milk, as monitored both by primary lipid oxidation products (lipid hydroperoxides) and by the secondary lipid oxidation product, hexanal. Fat-soluble antioxidants, β-carotene and α-tocopherol, analysed by HPLC, were not consumed during storage for either of the two types of buttermilk. In contrast, the antioxidative capacity of the serum phase decreased during storage as evaluated in a radical scavenging assay based on the semi-stable water-soluble radical nitrosodisulphonate (Fremy's salt). The time course for the decrease in water-soluble antioxidants was very similar for the two types of buttermilk suggesting that oxidation is initiated in the serum phase independently of fatty acid composition.
Cholesterol oxidation in feta cheese produced from high-temperature bleached and from non-bleached butteroil from bovine milk
- Jacob H. Nielsen, Carl Erik Olsen, Jeff Lyndon, John Sørensen, Leif H. Skibsted
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- Journal:
- Journal of Dairy Research / Volume 63 / Issue 4 / November 1996
- Published online by Cambridge University Press:
- 01 June 2009, pp. 615-621
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- November 1996
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During chill storage, cholesterol oxidation in feta cheese produced from bovine butteroil bleached at high temperature was compared with cholesterol oxidation in feta cheese produced from non-bleached butteroil. The bleaching was performed at two different temperatures, 265 and 280 °C, and the oil was bleached for 2·4, 3·8 or 4·3 min; a reference feta cheese was produced without bleaching. All cheeses were stored in brine at 4 °C, and cholesterol oxidation was measured during a storage period of 5 months. For the first 11 weeks of storage, the concentration of cholesterol oxides was comparable for the bleached feta cheeses, but on longer storage the concentration of oxysterols was highest in feta cheeses produced from the butteroil bleached at 280 °C. The bleaching temperature rather than the bleaching time affected cholesterol oxidation, which was minimal in the non-bleached reference cheese throughout the storage period compared with the bleached feta cheeses. 7-Ketocholesterol was found to be the dominant oxysterol in the feta cheeses at the end of the storage, comprising ∼ 50% of the total cholesterol oxides. In feta cheeses based on butteroil bleached at 265 °C, the concentration of 7-ketocholesterol ranged from 3·7 to 4·9 µg/g lipid at the end of the storage period, and in feta cheese based on butteroil bleached at 280 °C the concentration was 10·4–13·1 µg/g lipid. In the reference feta cheese the concentration of 7-ketocholesterol was 1·2 /µg/g lipid. There was no difference in yellowness, measured by tristimulus colorimetry as the Hunter b characteristic, of the feta cheeses bleached at 265 and 280 °C, and a small scale bleaching experiment with butteroil showed that it was possible to secure complete bleaching at temperatures down to 220 °C. We suggest that bleaching of butteroil for feta production should be performed at temperatures as low as possible in order to prevent cholesterol oxidation.
Cholesterol oxidation in butter and dairy spread during storage
- Jacob H. Nielsen, Carl Erik Olsen, Claus Jensen, Leif H. Skibsted
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- Journal:
- Journal of Dairy Research / Volume 63 / Issue 1 / February 1996
- Published online by Cambridge University Press:
- 01 June 2009, pp. 159-167
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- February 1996
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In a dairy spread (800 g lipid/kg, 10 g salt/kg) based on 750 g milk fat/kg and 250 g rapeseed oil/kg fat in 15 g extruded catering packaging, there was a more significant accumulation of cholesterol oxidation products than in butter (minimum 800 g lipid/kg, 12 g salt/kg) in 10 g extruded catering packaging when stored at 4 or at 20 °C. There was a lag phase of 7 weeks in cholesterol oxidation in dairy spread stored at 4 °C, while no lag phase was observed for storage at 20 °C. Total concentrations of oxysterols were, however, very similar for dairy spread stored at 4 and 20 °C after 13 weeks storage (∼ 12 μg/g milk lipid); storage at – 18 °C almost prevented cholesterol oxidation (∼ 4 μg/g milk lipid). For butter, cholesterol oxidation was less pronounced at 4 °C (< 3 μg/g milk lipid) than at – 18 °C (∼ 4 μg/g milk lipid) and 20 °C (∼ 7 μg/g milk lipid). 7-Ketocholesterol was the dominant oxidation product, with 1·3 and 5·7 μg/g milk lipid in butter and dairy spread respectively after 13 weeks storage at 4 °C.
Isolation and quantification of cholesterol oxides in dairy products by selected ion monitoring mass spectrometry
- Jacob H. Nielsen, Carl Erik Olsen, Christina Duedahl, Leif H. Skibsted
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- Journal:
- Journal of Dairy Research / Volume 62 / Issue 1 / February 1995
- Published online by Cambridge University Press:
- 01 June 2009, pp. 101-113
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- February 1995
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A method for isolation, detection and quantification of cholesterol oxidation products based on solid phase extraction in combination with preparative HPLC and gas chromatography–mass spectrometry selected ion monitoring has been developed for dairy products. The isolation procedure had a high recovery and artifact formation was minimal, as shown by isotope labelling. The limits of detection ranged from 0.3 to 35 pg/μl of the isomeric forms of 7-hydroxycholesterol, 20α-hydroxycholesterol, the isomeric forms of cholesterol-5,6-epoxides, cholestanetriol, 25-hydroxycholesterol and 7-ketocholesterol corresponding to a limit of quantification of 2–6 ng oxysterol/g lipid in the dairy product, depending on the nature of the cholesterol oxidation product.