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Zusammenfassung Es wird ein selbstentwickeltes Tiermodell mit Meerschweinchenfeten vorgestellt. Mit ihm sollen Aufnahme und Verteilung intraamnial injizierter Substanzen als Moglichkeit der kompensatorischen, paraplazentaren Ernahrung des Feten bei Plazentainsuffizienz untersucht werden. Das Tiermodell soll dazu beitragen, bisher noch nicht geloste Fragen der paraplazentaren Versorgung des Feten im Tierversuch zu klaren. In der vorliegenden Arbeit werden die Organgewichte der Feten in Abhangigkeit vom Gesamtgewicht dargestellt und uber erste Versuche zur Aufnahme von 14C-markierter α-Aminoisobuttersaure berichtet. Nach intraamnialer Injektion gelangte diese Modellsubstanz durch Abschlucken und intestinale Absorption in den Feten und von dort in das Muttertier und in weitere, nicht behandelte Feten. Feten am 50. Graviditatstag nahmen die Testsubstanz rascher auf als Feten am 60. Graviditatstag (Tragezeit bei Meerschweinchen insgesamt 65 Tage). Summary Uptake of nutrients from amniotic fluid; model studies with guinea pigs An experimental model with guinea pigs is described in which the uptake of nutrients by the foetus after intraamniotic application was measured. This is especially important as a way of compensatory paraplacental nutrition in cases of an insufficient function of the placenta. First studies on organ weights related to the size of the foetuses and on the uptake of α-aminoisobutryric acid (AIBA) are reported. After an injection of AIBA into the amniotic fluid this model substance is rapidly absorbed by the gastro-intestinal tract and transferred also to the dam and to the untreated foetuses. Absorption and distribution occurred more rapidly in 50-day than in 60-day foetuses (total gestation period in guinea pigs is 65 days). Resume A propos du prelevement de substances nutritives dans le liquide amniotique; recherches d'un modele avec des cobayes Un modele animal developpe avec des foetus de cobayes est presente. Ce modele doit permettre d'examiner la resorption et la repartition de substances infectees intraamniotiquement comme possibilite de nourriture compensatoire paraplacentaire pour des foetus lors d'insuffisance placentaire. Le modele devrait pouvoir expliquer des questions jusqu'alors non resolues concernant l'approvisionnement paraplacentaire du foetus dans un essai sur animaux. Les poids des organes du foetus en fonction du poids total sont decrits et on rapporte sur un premier essai l'absorption d'acide α-aminoisobutirique marque au 14C. Par injection intraamniotique, cette substance modele a penetre par voie buccale et absorption intestinale dans les foetus et de la dans la mere et chez les foetus non traites. Des foetus au 50e jour de gestation prennent plus rapidement la substance testee que les foetus au 60e jour de gestation. (Duree de la gestation chez le cobaye: 65 jours.) Resumen Sobre la toma de substancias nutritivas del liquido amniotico; estudios modelo con cobayas Se presenta un modelo animal, de creacion propia, con fetos de cobaya. Con el mismo se podran estudiar la incorporacion y distribucion de las substancias inyectadas por via intraamniotica como posibilidad de alimentacion paraplacentaria compensatoria del feto en casos de insuficiencia placentaria. El modelo animal pudiera contribuir a clarificar cuestiones no resueltas hasta ahora del abastecimiento paraplacentario del feto en el ensayo animal. En el trabajo presente se representan los pesos de los organos de los fetos en dependencia del peso total y los ensayos primeros sobre la absorcion de acido α-aminoisobutirico (AIBA) marcado con 14C. Tras la inyeccion intraamniotica penetro esta substancia modelo por deglucion y absorcion intestinal a los fetos y de ahi a la madre y a otros fetos que no habian sido tratados. Los fetos absorbieron mejor la substancia de prueba el dia 50° de gestacion que los fetos en el dia 60° de gestacion (la duracion de la gestacion en las cobayas es de 65 dias).

Zusammenfassung In zwei unabhangigen Laboratorien wurden 227 Milchproben auf ihren Harnstoffgehalt untersucht, wobei als Referenzmethode in einem Laboratorium nach Enteiweisung der Milch die „Test-Combination-Harnstoff” (Fa. Boehringer, Mannheim), die UV-photometrisch ausgewertet wird, zur Anwendung kam. Die gleiche Probe wurde in einem zweiten Laboratorium mit dem Teststreifen REFLOTEST®-Urea (Fa. Boehringer, Mannheim) untersucht, dessen Auswertung mit dem transportablen Reflexionsphotometer REFLOMAT® (Fa. Clinicon, Mannheim) vorgenommen wurde. Wie die statistische Auswertung des Methodenvergleichs zeigt (r = 0,95, y = 5,81 + 0,9 x), kann mit der uberpruften Teststreifen-Methode ausreichend zuverlassig der „wahre” Harnstoffgehalt in Milchproben ermittelt werden. Damit ist die REFLOTEST®-Urea/REFLOMAT®-Methode eine einfache und praxisgerechte Moglichkeit zur Harnstoffbestimmung in der Milch. Danksagung Fur die technische Assistenz bedanken wir uns bei Fraulen Y. Handel, P. Maltritz und L. Mantel. Summary Determination of urea in milk using strips (REFLOTEST®-Urea) and reflection photometer (REFLOMAT®) Urea concentration was determined in 227 milk samples by two independent laboratories. One laboratory employed, as the method of reference, the “Test-Combination Urea” — a UV photometric test — (Boehringer Mannheim) after removal of protein. In the second laboratory, “REFLOTEST®-Urea” strips (Boehringer Mannheim) were evaluated with the transportable reflection photometer “REFLOMAT®” (Clinicon Mannheim). Statistical analysis (r = 0.95; y = 5.81 + 0.9 x) revealed that “true” urea concentrations of milk samples can be determined with sufficient accuracy by the test strip method. Thus, “REFLOTEST®-Urea/REFLOMAT®” offers a simple and accurate method for determination of urea in milk in practice. Resume Determination de taux d'uree dans le lait au moyen du test a bandes (REFLOTEST®-Urea) et par depouillement reflectometrique (REFLOMAT®) Le taux d'uree de 227 echantillons de lait a ete examine dans deux laboratoires independants l'un de l'autre. Un des laboratoires a utilise apres avoir elimine les proteines du lait le «Test-Combination-Uree» (Maison Boehringer, Mannheim) qui est interprete photometriquement aux UV; l'autre laboratoire a employe les bandes de test REFLOTEST®-Urea (Maison Boehringer, Mannheim) qui sont interpretees avec le photometre a reflechissement transportable REFLOMAT® (Maison Clinicon, Mannheim). Etant donne que la valeur statistique de la methode comparee a donne r = 0,95, y = 5,81 + 0,9 x, le taux «veritable» de l'uree dans des echantillons de lait peut etre considere comme fiable en utilisant la methode examinee des bandes de test. Le REFLOTEST®-Urea/methode REFLOMAT® est donc une methode simple et pratique pour determiner l'uree dans le lait. Resumen Valoracion del contenido de urea en la leche mediante las bandas de prueba (REFLOTEST®-urea) y por analisis reflectometrico (REFLOMAT®) Se examinaron en dos laboratories independientes 227 muestras de leche en cuanto a su contenido en urea, empleandose en un laboratorio tras desproteinizacion de la leche la «combinacion de prueba-urea» (firma Boehringer, Mannheim), la cual evalua fotometricamente en luz UV. Se examino la misma muestra en un segundo laboratorio con las bandas de prueba REFLOTEST®-urea (firma Boehringer, Mannheim), cuya evaluacion se llevo a cabo con el fotometro de reflexion transportable REFLOMAT® (firma Clinicon, Mannheim). Como muestra la evaluacion estadistica de la comparacion de los metodos (r = 0,95, y = 5,81 + 0,9 x), con el metodo sobrecontrolado de las bandas de prueba se puede determinar de una forma suficientemente fiable el contenido «verdadero» de urea en las muestras de leche. Con ello, el metodo REFLOTEST®-urea/REFLOMAT® ofrece una posibilidad simple y al alcance de la practica rural para determinar la urea en la leche.

Zusammenfassung Opaque-2-Mais (HL) wurde mit normalem Hybridmais (NL) des gleichen Anbau-gebietes verglichen, der allerdings einen uberdurchschnittlich hohen Lysingehalt auf-wies. Der HL-Mais enthielt 4,7% Lysin und 1,2% Tryptophan im Protein, der NL-Mais 3,3% Lysin und 0,8% Tryptophan. Der HL-Mais hatte einen hoheren Protein-, Asche- und Phosphorgehalt und ent-hielt auserordentlich wenig Carotin und Xantophyll. Im ubrigen bestanden nur geringe Unterschiede in der Zusammensetzung. In Rattenversuchen wurden mit HL-Mais wesentlich hohere Gewichtszunahmen und PER-Werte erhalten. Die Differenz zum NL-Mais konnte ausgeglichen werden. wenn diesem die entspredienden Lysin- und Tryptophanmengen zugesetzt wurden. HL-Mais lies sich durch Lysinerganzung noch verbessern. Tryptophan erbradite keine weitere Verbesserung, wenn es dem lysinerganzten HL-Mais zugelegt wurde. Der Proteinwert von methioninerganztem Kasein wurde von HL-Mais nicht erreicht. Bei Wachtelkuken war HL-Mais dem NL-Mais stets deutlich uberlegen. Diese Differenz nahm mit steigender Proteinkonzentration ab. Lysinerganzung von NL-Mais verbesserte dessen Proteinqualitat fur Wachtelkuken. Zusatzliche Gaben von Tryptophan oder Tryptophan, Arginin und Glycin waren ohne Wirkung. Die Qualitat des HL-Maises wurde erreicht, wenn zusatzlich noch das weite Leucin/Isoleucinverhaltnis durch Isoleucinzugabe korrigiert wurde. Methionin-zulagen erbrachten in keinem Falle Wachstumsverbesserungen. Bei Wachtelhennen, die Rationen mit 8 bzw. 12% Protein erhielten, fiel die Lege-leistung weniger stark ab, wenn HL-Mais an Stelle von NL-Mais verwendet wurde.

Zusammenfassung In zwei Versuchen an 1260 Mastkuken mit praxisnahen Rationen und in drei weiteren Futterungsexperimenten an 2868 Broilern mit halbsynthetischen Rationstypen wurden die Alkanhefen Lavera und Toprina im Austausch gegen Fischmehl- und/oder Sojaprotein eingesetzt. Bei Einhaltung einer Schwefelaminosaurenkonzentration von 3,6 bis 3,8 % vom Rohprotein konnten 38 % des Rationsproteins (ca. 15% der Futtermischung) wirkungsgleich durch Eiweis der Alkanhefen ersetzt werden (Versuch II). 20 % Hefe im Futter (54 % des Rationsproteins) erzeugten dagegen deutliche Leistungsdepressionen (Versuch I). Wurde Hefe (methionin- und argininerganzt) als alleinige Proteinquelle verwendet, musten im Vergleich zu Fischmehl- bzw. Sojakontrollgruppen in alien gepruften Konzentrationen (20, 30 und 40 % der Ration) erhebliche Wachstumsdepressionen und eine signifikante Erhohung der Mortalitat in Kauf genommen werden. Dieser negative Effekt war mit steigenden Hefekonzentrationen in der Ration starker ausge-pragt. Der Leistungsunterschied zu den Soja- bzw. Fischmehlgruppen konnte durch Vitamin-E-Zusatz (75 ppm) und/oder Selenerganzung (0,3 ppm) zur Basalration (25 ppm Vitamin E) zwar verringert, jedoch nicht ausgeglichen werden.

Zusammenfassung An einem schonend getrockneten und einem aus derselben Milch hergestellten scharf getrockneten Magermilchpulver wurden analytische und tierexperimentelle Untersuchungen uber die bei der Hitzebehandlung auftretenden Aminosaurenschadigungen durchgefuhrt. Bei der verscharften Milchpulvertrocknung kam es zu einem Abfall an Lysin von 8,9 auf 5,8%, an verfugbarem Lysin (Dinitrofluorbenzolmethode) von 6,6 auf 2,2% und an Cystin von 1,0 auf 0,8% (alle Werte in g/16 g N). Die ubrigen Aminosauren wurden der Analyse nach zu urteilen nicht oder nur geringfugig beeinflust. Hohe Anteile an Furosin, einem durch salzsaure Hydrolyse entstehenden Folgeprodukt des Epsilon-Fruktoselysins oder Epsilon-Laktuloselysins, liesen darauf schliesen, das der groste Teil des in Verlust geratenen Lysins, gebunden als ernahrungsphysiologisch inaktiver Lysin-Zucker-Komplex, vorlag. Nach einer Testmahlzeit des hitzegeschadigten Milchpulvers ergab sich bei erwachsenen Ratten eine im Vergleich zur schonend getrockneten Probe deutlich geringere Anflutung fur das Lysin im Pfortaderplasma. Weitere Aminosauren waren offensichtlich nicht geschadigt worden (Cystin wurde nicht untersucht). Durch Zusatz des ernahrungsphysiologisch in Verlust geratenen Lysins wurde die Proteinqualitat der schonend getrockneten Vergleichsprobe nahezu wieder erreicht, was ebenfalls fur die fast selektiv zu nennende Lysinschadigung bei verscharfter Milchtrocknung spricht.

Zusammenfassung An insgesamt 32 Proben Weizen, Weizenkeime, Weizennachprodukte and Weizenmehle wurden Aminosaurenanalysen durchgefuhrt. Von den 32 untersuchten Proden entsprachen nur 22 ihrem Nahrstoffgehalt nach der Handelsbezeichnung. Die meisten als Weizenbollmehle un Weizennachmehle Deklarierten Proben erwiesen sich als Weiznkleien bzw. als Weizenfuttermehle. Sehr grose Unterschiede in der Rohnahrstoffzusammensetzung und im Aminosaurenmuster ergaben sich bei den Weizenkeimen. Einwandfreie Weizenkeime wicsen von allen untersuchten Proben die gunstigste Aminosaurenzusammensetzung fur den Bedarf der landwirtschafilichen Nutztiere auf. Es waren lediglich Methionin, moglicherweise auch Phenylalanin plus Tyrosin limitierend. Die untersuchten Proben Weizenkleie, Weizenbollmehl und Weizenfuttermehl waren untereinander im Aminosaurenmuster sehr einheitlich. Die Aminosauren Lysin, Threonin, Valin, Asparaginsaure, Arginin und Glycin nahmen in der Reihenfolge Keime, Futterkeime, Kleie, Futtermehl, Nachmehl, Mehl Type 405 ab. In derselben Reihenfolge stiegen die Gehaltswerte fur Glutaminsaure, Prolin und Phenylalanin an. Das Ergebnis der Untersuchungen an Proben aus dem Handel wurde durch Analysen an Nachprodukten von zwei Vermahlungen derselben Ausgangsware (Inlandweizen und Inlandweizen 75% plus Manitobaweizen 25%) bestatigt. Der Manitobaweizen unterschied sich in der Aminosaurenzusammensetzung trotz des wesentlich hoheren Proteingehalts (17,2% gegeniiber 12,1%) nur wenig vom Inlatidweizen. Die Muhlennachprodukte der Vermahlung Inlandweizen enthielten mehr Lysin als die Nachprodukte der Mischung Inland-Manitoba.

Zusammenfassung Fur die Proteinbewertung von Eiweisfuttermitteln durch Ermittlung einer wert-bestimmenden Aminosaure scheint die Methode nach Carpenter zur Bestimmung von verfugbarem Lysin mit Dinitrofluorbenzol besonders geeignet zu sein. Diese Methode wurde daher ubernommen, fur die Routineanalytik etwas vereinfacht und an verschiedenen Futtermitteln uberpruft. Die Reproduzierbarkeit des Verfahrens erwies sich als sehr gut. Die Variations-Koeffizienten, berechnet aus Untersuchungen an zwei Fischmehlen, waren 0,8 % bzw. 1,6 %. Storende Substanzen beeinflussen die Analysengenauigkeit bei einem Lysingehalt von uber 1 % in der lufttrockenen Substanz nur in geringem Mase. Vergleiche der Ergebnisse mit Werten an Gesamtlysin, bestimmt mittels der Ionenaustausch-chromatographie nach Saurelydrolyse, zeigten eine gute Ubereinstimmung (Mittel aus 23 Fischmehlen: 8,5 g Gesamtlysin/16 g N; 7,0 g verfugb. Lysin/16 g N). Die Bestimmung von DNFB-verfugbarem Lysin in zusatzlich hitzebehandelten Fischmehlen ergab einen von der Zeit der Erhitzung abhangigen Lysinabfall, der bei Anwesenheit von Glucose noch verstarkt war. Nach stattgefundener Karamelisation, die eine hoch-gradige Lysinschadigung bedeutete, trat eine storende Farbe auf, deren Absorptions-maximum bei Λ = 340 mμ lag. Versuche zur Sterilisation von Rattenfutter erbrachten einen von der Art und Dauer der Behandlung abhangigen Abfall an verfugbarem Lysin bis zu 11 %. Diese Unterschiede liegen jedoch noch innerhalb der bei dem geringen Lysingehalt des Futters hohen Fehlergrenze. Ein Einflus des Pelletierens auf den Gehalt an verfugbarem Lysin war nicht feststellbar. Wie Untersuchungen an Testgemischen zeigten, ist auch eine Beurteilung kohlenhydratreicher Futtergemische bei einem Lysingehalt von uber 1 % in der lufttrockenen Substanz mit der Methode nach Carpenter moglich. Der in den einzelnen Bestandteilen bestimmte Lysingehalt wurde zu 93 % durch die Bestimmung in der Mischung wiedergefunden (Mittel aus 13 Testgemischen).

Zusammenfassung Fur die Proteinschadigung wahrend der Herstellung und Lagerung von Eiweisfuttermitteln werden Reaktionen vom Typ der Maillardkondensation und weitere, noch weitgehend unbekannte Umsetzungen verantwortlich gemacht. Hierbei ist vor allem die Bindung von freien Aminogruppen mit reaktionsfahigen Carboxyl-Hydroxyl- und Seitengruppen im Proteinverband bedeutend. Auserdem wird die Kondensation freier Aminogruppen mit Abbauprodukten oxydierter Fettsauren diskutiert. In der vorliegenden Arbeit wurde versucht, inwieweit sich in hitzegeschadigten Modellgemischen aus Casein mit Glukose Aminosaurenschadigungen nachweisen lassen. Die Trocknung eines Gemisches aus Casein mit 20% Glukose und der doppelten Menge Wasser bei 105°C erbrachte eine deutliche Verminderung der scheinbaren Verdaulichkeit des Rohproteins. Die Verdaulichkeit fur Threonin, Isoleucin, Glutaminsaure und Serin war geringer als die Verdaulichkeit des Proteins. Bei Futterung einer Ration mit 2% tryptophanerganzter Gelatine und 8% Protein aus dem hitzegeschadigten Casein an wachsende Ratten erweisen sich Methionin als erste sowie vermutlich Threonin und Lysin als zweite und dritte limitierende Aminosaure. Die Trocknung eines Modellgemisches aus Casein mit 10% Glukose (Casein: Wasser = 1:1) bei 90°C bewirkte wie in Versuch 1 eine starke Lysinschadigung. Die scheinbare Verdaulichkeit des Lysins betrug 86% der Verdaulichkeit des Lysins im unerhitzten Protein. Sie war damit wesentlich geringer als die relative Verdaulichkeit des Proteins (97%). Es wird vermutet, das in diesem Versuch die Lysinschadigung vor allem eine Lysin-Inaktivierung bedeutet hatte. Neben dem Lysin waren von den essentiellen Aminosauren das Isoleucin und das Threonin in der Verdaulichkeit beeintrachtigt. Bei Futterung einer Ration mit 8% Protein aus dem hitzegeschadigten Casein an wachsende Ratten waren Methionin, Lysin und Threonin die erste, zweite und dritte limitierende Aminosaure. Es wird aus den Versuchen geschlossen, das durch die Hitzeschadigung von den essentiellen Aminosauren neben dem Lysin zumindest noch das Threonin in seiner Verfugbarkeit beeintrachtigt worden war.

For several years, nutrient profiling has been discussed as a regulatory instrument for health claims made on foods. The aims of the European Commission are mainly to protect consumers from misleading and even dangerous information and to ban advertisements for foods and menus for children if they are not healthy. Generally, nutrient profiling will be established on the basis of contents of different nutrients and substances like fat, saturated fat, trans fatty acids, salt/sodium and sugars ‘whose excessive intakes in the overall diet are not recommended and those such as poly- and monounsaturated fats, available carbohydrates other than sugars, vitamins, minerals, protein and fiber’. In the present paper, 4 out of >20 proposals will be discussed: the US requirement for health claims (FDA Code), the ‘a little a lot’ system from the UK, the ‘tripartite classification’ model of the Netherlands and the FSA scoring system from the UK. At present, several details remain uncertain, e.g. the reference basis (100 g, serving size or 100 kcal, respectively), moreover the use of thresholds or a scoring system. The evaluation may be ‘across the board’ versus in categories, respectively. In all cases, exceptions will be necessary.

Die Begriffsbestimmungen fur das Lebensmittel Fleisch sind in jedem Land individuell geregelt. Gemas den in Deutschland geltenden Leitsatzen fur Fleisch und Fleischerzeugnisse fallen unter den Sammelbegriff Fleisch „alle Teile von geschlachteten oder erlegten warmblutigen Tieren, die zum Genuss fur den Menschen bestimmt sind. Hierbei handelt es sich um Fleisch und Geflugelfleisch, das zuvor nach fleisch- und geflugelfleischhygienischen Vorschriften untersucht und als tauglich zum Genuss fur Menschen beurteilt wurde“. Das Muskelgewebe umfasst das Skelettmuskelgewebe mit eingebettetem Fett- und Bindegewebe. Zu den warmblutigen Tieren, die zum Verzehr dienen, zahlen in Deutschland vor allem Rinder, Kalber, Schweine, Schafe, Ziegen, Pferde, Geflugel, Kaninchen und Wild. In anderen Landern und Kulturkreisen wird auserdem das Fleisch von Buffel, Bison, Kamel, Rentier, Straus, Kanguru, Robbe, Hund, Katze, Schlange, Alligator, Schildkrote und anderen Tieren in gewissem Umfang verwendet.

Fisch spielt seit langer Zeit eine bedeutende Rolle in der Ernahrung des Menschen. Die altesten Fundstucke, die eindeutig auf Fischfang hindeuten, sind Angelhaken von etwa 8.000 v. Chr. Wahrscheinlich wurde Fisch aber schon wesentlich fruher von Menschen, die in der Nahe von Flussen, Seen oder Meeren lebten, als Lebensmittel genutzt. Im Laufe der Zeit wurden vielfaltige Fanggerate entwickelt, die auch heute noch Einsatz finden.

Melanoidins are formed during household cooking procedures and are part of our daily diet, but data on their toxicological potential are still scarce. Therefore, the mutagenic, cytotoxic and genotoxic activity of the water soluble total fraction (sol A), the water soluble high molecular weight fraction (HMW; Molecular weight > 12,400 Da) and the remaining water soluble low molecular weight fraction (LMW) isolated from a glucose–glycine model system roasted at 125 °C was comprehensively studied in human lymphocytes (genetic end point: sister chromatid exchange (SCE)), Caco-2 cells (SCE, cell viability, cell proliferation) and in the Salmonella typhimurium strains TA98 and TA102 (Ames test). Tests were performed in a dose- and time-dependent manner. The results indicate a significant increase in SCE formation in human lymphocytes after the exposure to 0.05% and 0.1% of the melanoidin fractions. In Caco-2 cells, only the exposure to LMW increased the SCE formation as a matter of concentration. Cell's proliferation and viability decreased significantly after exposure to melanoidins. In the AMES test, melanoidins did not show a mutagenic potential, neither using the TA98 nor the TA102 strain. These results show that melanoidins isolated from the glucose–glycine mixture exhibited modest but significant genotoxic effects in human lymphocytes and, in particular the LMW, in Caco-2 cells, but they induce neither in low nor in very high concentrations mutagenicity in bacteria strains.

The aim of the present study was to apply an activity-guided screening procedure to coffee brew to identify a key chemopreventive compound by means of in vitro antioxidant tests as well as cell culture experiments and to prove the in vivo activity of that compound by an animal feeding experiment. Solvent fractionation, followed by multiple-step ultrafiltration, revealed that the polar coffee compounds with molecular weights below 1 kDa show the major inhibitory effect on the in vitro peroxidation of linoleic acid as well as the predominant chemopreventive enzyme modulating activity on the NADPH-cytochrome c reductase (CCR) and glutathione S-transferase (GST) in human intestinal Caco-2 cells. To identify the chemical structure of the most active antioxidants and chemopreventive compounds, the polar compounds were further separated by HPLC techniques, followed by the activity-guided screening of the individual HPLC fraction. These experiments demonstrated 5-chlorogenic acid to be the most powerful antioxidant in vitro, whereas, in contrast, chemopreventive effects on the GST activity were found for the N-methylpyridinium ion, the structure of which was elucidated by LC-MS and NMR experiments and confirmed by synthesis. The in vivo activities of coffee beverage and N-methylpyridinium ions were tested in a 15-day feeding experiment on rats. In the liver, feeding of 4.5% coffee beverage resulted in increases of GST and UDP-GT activities by 24 and 40% compared to animals fed the control diet (p > 0.05), respectively. Plasma total antioxidant capacity and plasma tocopherol were elevated in animals fed the coffee beverage and the N-methylpyridinium-containing diet. In summary, the results demonstrating a strong in vitro antioxidant activity for coffee were confirmed by the feeding study. Surprisingly, feeding of N-methylpyridinium also resulted in an increased total antioxidant capacity in the plasma. The data indicate that the mode of action demonstrated for N-methylpyridinium in biological systems is different from that in foods.

Melanoidins, the brown-colored polymers formed through Maillard type reaction in several heat-treated foods, represent a significant part of our diet, with an average intake of grams per day. Most of the studies on the physiological effects of these compounds have been performed using the water soluble melanoidin fractions. But dietary melanoidins formed on the surface of bakery products are poorly soluble in water as well as in organic solvents. In this work, an enzymatic solubilization procedure was developed on a gluten-glucose model system and it was applied to bread and biscuits. The soluble material obtained was tested for its antioxidant activity, for its effect on phase-I and phase-II xenobiotic enzymes and for potential cytotoxic effects. Soluble melanoidins from model system and biscuits exhibit a strong antioxidant activity and do not show any cytotoxicity on Caco-2 cells. Melanoidins extracted from biscuits was able to inhibit the activity of Phase I (NADPH-cytochrome-c reductase) and Phase II (Glutathione-S-transferase) enzymes, whereas the low molecular weight melanoidins isolated from gluten-glucose model system inhibit the activity of NADPH-cytochrome-c reductase.

The objective of the study was to analyse macronutrient and food intakes of regular users (310 men, 495 women) and nonusers (1136 men, 1269 women) of vitamin and mineral supplements, aged 18-79 years. These, were participants of the German Nutrition Survey, which was part of the German National Health Interview and Examination Survey 1998. Information on dietary behaviour including supplementation habits was assessed using a validated computerised dietary history method (DISHES 98). There were no major differences in macronutrient intakes between regular users and nonusers. After adjustment for age, energy intake, smoking, sport activity, socio-economic status and East/West German residence, regular supplement use was associated with a higher consumption of drinking water. Among men, a higher consumption of vegetable fat, poultry and fruit/vegetable juice, and among women, a higher consumption of fish, milk products, fruits and tea was also associated with regular supplement use. An inverse association was observed between regular supplement use and the consumption of coffee among women. Significant differences in food consumption between regular users and nonusers were observed, indicating a tendency for a healthier food choice among regular users.

N e -carboxymethyllysine (CML) is an advanced-glycation endproduct found in both heat-treated foods and in living organisms. In the experiments described below, we have evaluated the effects of CML on the expression of the detoxification enzyme, glutathione- S -transferase, in the rat and in intestinal cells in cell culture. In the first animal experiment, casein-linked CML was administered to Wistar rats at two pharmacological doses (110 and 300 mg CML/kg body weight/day) for 10 days. Phase II glutathione- S -transferase (GST) enzyme activity was analysed in the kidneys. In a second study, CML was administered in a diet supplemented with bread crust (25% w/w) such that rats received a moderate dose of 11 mg CML/kg body weight/day. The induction of GST isoenzymes was analysed in the kidneys. In vitro experiments were also performed to study the effects of casein-CML and bread crust on GST induction in the intestinal Caco-2 cell line. Both animal experiments revealed an inductive effect of casein-linked CML and of bread crust on GST activity in the kidneys. The results obtained from the cell culture experiments by enzyme activity analysis and Western blotting confirmed these inductive effects on the GST. In conclusion, dietary-advanced glycation products containing CML were shown to enhance the expression of GST in both animal models and in cell culture.

4-Desmethylsterols and -stanols reduce plasma total cholesterol (TC) and LDL cholesterol by inhibition of intestinal cholesterol absorption, while the cholesterol-lowering potential of 4,4′-dimethylsterols is less well defined. The present study aimed to compare the effects of 4-desmethylsterols, -stanols, and 4,4′-dimethylsterols on plasma and hepatic cholesterol, sterol excretion and bile acid metabolism. Male golden Syrian hamsters were fed diets containing 13 g/100 g fat, 0·08 g/100 g cholesterol and 0 (control), 0·24 or 0·48 % (w/w) esterified 4-desmethylsterols (sterols) and esterified hydrogenated 4-desmethylsterols (stanols) from common vegetable oils or esterified 4,4′-dimethylsterols from rice bran oil for 5 weeks. Sterol and stanol esters at the dose of 0·24 % were equally effective and significantly (PP

RAGE (receptor for advanced glycation end products) is a multiligand cell surface molecule of the immunoglobulin superfamily. It was originally described as a receptor for protein adducts formed by glycoxidation (AGEs) that accumulate in diseases such as diabetes and renal failure. Performing RT-PCR and Western blot analysis we intended to determine RAGE expression in the human colon adenocarcinoma cell line Caco-2. Moreover, Caco-2 cells were incubated in the presence of AGEs. Since RAGE ligation triggers the p21(ras) signal transduction pathway the activation state of p44/42 (ERK1/2) MAP kinases was determined. Here we demonstrate for the first time that Caco-2 cells express RAGE and that administration of the food-derived casein-linked AGE N(epsilon)-(carboxymethyl)lysine (Cas-CML) results in Caco-2 p44/42 (ERK1/2) MAP kinase activation.

In several studies, the absorption and urinary excretion of free and protein bound Amadori products were measured in rats and humans. Both, in vitro tests with everted intestinal sac preparations and in vivo experiments, showed that there is no active intestinal transport of these compounds but an absorption by diffusion. Trials with tissue slices have shown that there was an uptake into the cells of the liver, kidneys and muscles. Metabolism of Amadori products, if it exists in animals, tends to be very low. Micoorganisms in the large intestines decompose the Amadori products almost completely. The profile of urinary excretion of Amadori products after the ingestion of test meals showed a rapid elimination of the absorbed part, while the fecal output, although low because of the hind gut fermentation, persisted up to 3 days. Only 1-3% of the ingested amounts of protein bound Amadori products were recovered in the urine, which suggests a low absorption rate.

Metabolic transit data on food-borne advanced MRPs (Maillard reaction products) termed melanoidins are yet not completely elucidated and it is still an open question whether isolated melanoidin structures undergo metabolic biotransformation and subsequently cause physiological effects in vivo. Advanced MRPs, acting as premelanoidins, and melanoidins are formed under severe heat treatment of foods and are ingested with the habitual diet at considerable amounts. Metabolic transit data are known for Amadori compounds classified as early MRPs, like, e.g., fructose-lysine. For rats and humans, the percentages of ingested free versus protein-bound fructose-lysine excreted in the urine were found within ranges of 60–80% and 3–10%, respectively. Balance studies on free advanced MRPs are still lacking, but protein-bound low-molecular-weight premelanoidins and high-molecular-weight melanoidins have already been investigated in animal experiments using 14C-tracer isotopes. The amount of ingested radioactivity absorbed and excreted in the urine was found at levels ranging from 16 to 30% and from 1 to 5% for premelanoidins and melanoidins, respectively. These different metabolic transit data of premelanoidins and melanoidins can be explained by the following mechanisms involved: (i) intestinal degradation by digestive and microbial enzymes; (ii) absorption of these compounds or their degradates, and (iii) tissue retention. Structure specific in vivo effects have been identified for protein-bound premelanoidins on intestinal microbial activity, xenobiotic biotransformation enzymes and further glycation reactions. The latter are hypothesized to be involved in the aging process and in the course of different diseases. Further investigations are needed to clarify synergistic in vivo effects of dietary ingested melanoidins and endogenously formed glycation products.

Zusammenfassung Hitzegeschadigte Proteine mit einem hohen Gehalt an Fruktoselysin, dem wichtigsten Reaktionsprodukt von Lysin mit Glukose oder Laktose, wurden zusammen mit Darminhalt von Ratten inkubiert. Als Kontrollen dienten Ansatze, die zur Abtotung der Mikroorganismen mit Sublimat versetzt waren. Wie die Versuche ergaben, sind Mikroorganismen aus dem Verdauungstrakt befahigt, das fur hohere Tiere nicht spaltbare und nicht resorbierbare Fruk-toselysin abzubauen. Wir danken der Deutschen Forschungsgemeinschaft fur Unterstutzung der Versuche. Summary Degradation of fructoselysine by the intestinal flora Heat damaged proteins with high contents of fructoselysine were incubated with gut contents of rats. Controls has been mixed before incubation with sublimate in order to stop the action of microorganisms. Fructoselysine is neither utilized by the animal nor absorbed as an intact molecule. Our results show however, that fructoselysine was deaminated by the microorganisms of the rats intestinal tract. Resume Degradation de la fructoselysine par la flore intestinale On incube avec le contenu intestinal de rats, des proteines denaturees a la chaleur, a forte teneur en fructoselysine, qui est le produit de reaction le plus important de la lysine avec le glucose ou le lactose. Comme controles, on emploie les preparations qu'on a combinees avec du sublime pour detruire les microorganismes. Comme les resultats l'ont montre, les microorganismes du tractus digestif sont capables de degrader la fructoselysine ne pouvant etre scindee, ni resorbee par les animaux superieurs. Resumen Desintegracion de la fructosalisina mediante la flora intestinal Junto con contenido enterico de ratas se incubaron proteinas, danadas por el calor, con uncontenido elevado en fructosalisina, el producta de reaccion mas importante de la lisina con la glucosa o lactosa. Como testigos se utilizaron siembras que se habian tratado con sublimado para matar los micro-organismos. Como prueban estos ensayos, los microbios del tracto digestivo son capaces de desintegrar la fructosalisina, que los animales superiores no escinden ni resorben.

A modified RP-HPLC method for the determination of lysinoalanine (LAL) with dansyl chloride derivatisation without solid-phase extraction is presented. The method was applied to market samples of liquid milk ( n =54) and cheese ( n =32) as well as to human milk from healthy volunteers ( n =12). Additional liquid milk samples were obtained from model experiments on falling stream heating (FSH) high-pasteurisation ( n =40). In raw milk, pasteurised and FSH high-pasteurised milk products LAL was quantified for the first time. The LAL contents analysed in raw and pasteurised milk ranged from 4 to 24 and 17 to 69 mg kg −1 crude protein, respectively. Compared to that, UHT-treated milk and sterilised milk showed higher LAL levels up to 186 and 653 mg kg −1 crude protein, respectively. Among all of the dairy samples, LAL was proven to be a suitable and sensitive indicator to assess the heat treatment intensity given to milk which was heated without and with the addition of dairy-based substitutes, like caseinates.

This study examined the effects of various cereal fibers and various amounts of β-glucan on cholesterol and bile acid metabolism. Hamsters were fed semisynthetic diets containing 0.12% cholesterol, 20% fat, and either 16% total dietary fiber (TDF) from wheat bran (control) or 10% TDF from oat bran, 13% TDF from oat bran concentrate or barley grains, 16% TDF from oat fiber concentrate, barley flakes, or rye bran. After five weeks, plasma total cholesterol and liver cholesterol concentrations were significantly lower (20 and 50%, respectively) only in hamsters fed rye bran. Diets containing any of the oat ingredients or barley had no effect on total cholesterol. Changes in the pattern of biliary bile acids occurred in hamsters fed 16% TDF from barley flakes or 10% TDF from oat bran. Hamsters fed rye bran had a significantly higher fecal bile acid excretion when compared with controls fed wheat bran. Because rye bran caused the most pronounced lowering effect of total cholesterol despite the lowest ...

A modified reversed-phase-HPLC method with o-phthalaldehyde pre-column-derivatisation for determination of N ϵ -carboxymethyllysine in food samples is presented. It is shown, that the method has to be modified if applied to milk products, including specific modifications in sample preparation and chromatographic separation conditions. The increased selectivity of a double endcapped RP 18 phase is necessary for reliable separation of N ϵ -carboxymethyllysine in hydrolysates of complex products like cheese. With a detection limit of 0.5 pMol the method shows high sensitivity and a very good reproducibility ( s =2.81%). In total, several different milk products ( n =50) as well as fresh, processed and ripened cheese samples ( n =50) were analysed. The highest amounts of N ϵ -carboxymethyllysine were found in a whey cheese (1016 mg/kg protein), evaporated milk (1691 mg CML/kg protein), coffee cream (613 mg CML/kg protein) and cocoa milk (413 mg CML/kg protein). N ϵ -carboxymethyllysine could not be detected in UHT milk, fresh, processed and ripened cheese. The results show that N ϵ -carboxymethyllysine can give valuable information on lysine damage in severely heat-treated milk products and in products, with added sugar, pre-damaged constituents or stabilising agents. ©

The lipid-lowering effect of psyllium (PSY) is well established. Enhanced fecal bile acid excretion and a stimulation of hepatic bile acid synthesis are discussed as primary mechanisms of this action. To further examine the effect of bile acid excretion and specifically of compositional alterations in the bile acid pool on the cholesterol-lowering and gallstone-preventing action of PSY, male golden Syrian hamsters were fed lithogenic diets containing 5 g/100 g fat, 0.4 g/100 g cholesterol and 0 (control), 4 or 6% PSY or 1% cholestyramine (CHY). PSY significantly lowered plasma total cholesterol and triacylglycerol at a magnitude comparable to that induced by CHY. Although hepatic cholesteryl ester accumulation was completely inhibited by CHY, PSY did not prevent the hepatic storage of esterified cholesterol. PSY and CHY caused distinct alterations in the bile acid profile. PSY caused a selective reduction of taurine-conjugated bile acids, especially of taurochenodeoxycholate. As a result, the glycine:taurine conjugation and the cholate:chenodeoxycholate ratios were significantly higher in PSY-fed hamsters. PSY and CHY normalized the lithogenic index and prevented cholesterol gallstone formation compared with controls. Daily fecal bile acid excretion was approximately 400% greater in hamsters fed 6% PSY, whereas CHY caused an 11-fold increase. Daily neutral sterol excretion did not differ in PSY-fed hamsters but was >100% greater in those fed CHY than in controls. These data emphasize the potent lipid-lowering effect of PSY. Increased fecal bile acid excretion and alterations of the circulating bile acid pool by removal of dihydroxy bile acids (e.g., taurochenodeoxycholate) appear to be main modulators of the hypocholesterolemic action of PSY by leading to an up-regulation of hepatic bile acid synthesis.

To examine the impact on bile acid metabolism and fecal steroid excretion as a mechanism involved in the lipid-lowering action of beta-cyclodextrin and resistant starch in comparison to cholestyramine, male golden Syrian hamsters were fed 0% (control), 8% or 12% of beta-cyclodextrin or resistant starch or 1% cholestyramine. Resistant starch, beta-cyclodextrin and cholestyramine significantly lowered plasma total cholesterol and triacylglycerol concentrations compared to control. Distinct changes in the bile acid profile of gallbladder bile were caused by resistant starch, beta-cyclodextrin and cholestyramine. While cholestyramine significantly reduced chenodeoxycholate independently of its taurine-glycine conjugation, beta-cyclodextrin and resistant starch decreased especially the percentage of taurochenodeoxycholate by -75% and -44%, respectively. As a result, the cholate:chenodeoxycholate ratio was significantly increased by 100% with beta-cyclodextrin and by 550% with cholestyramine while resistant starch revealed no effect on this ratio. beta-Cyclodextrin and resistant starch, not cholestyramine, significantly increased the glycine:taurine conjugation ratio demonstrating the predominance of glycine conjugated bile acids. Daily fecal excretion of bile acids was 4-times higher with 8% beta-cyclodextrin and 19-times with 1% cholestyramine compared to control. beta-Cyclodextrin and cholestyramine also induced a 2-fold increase in fecal neutral sterol excretion, demonstrating the sterol binding capacity of these two compounds. Resistant starch had only a modest effect on fecal bile acid excretion (80% increase) and no effect on excretion of neutral sterols, suggesting a weak interaction with intestinal steroid absorption. These data demonstrate the lipid-lowering potential of beta-cyclodextrin and resistant starch. An impaired reabsorption of circulating bile acids and intestinal cholesterol absorption leading to an increase in fecal bile acid and neutral sterol excretion is most likely the primary mechanism responsible for the lipid-lowering action of beta-cyclodextrin. In contrast, other mechanisms involving the alterations in the biliary bile acid profile or repressed hepatic lipogenesis, e.g., VLDL production, appear to be involved in the hypolipidemic effect of resistant starch.

Recent studies have suggested that monounsaturated fatty acid (MUFA)-rich dietary fats do not have the same plasma cholesterol-lowering effects whereby rapeseed oil was more effective than olive oil. This phenomenon could be explicable by the content of other fatty acids or plant sterols. To further evaluate the effects of different MUFA-rich oils (18:1-rich sunflower oil, rapeseed oil, olive oil) in comparison to polyunsaturated (PUFA)-rich oils (18:2-rich sunflower oil) and saturated fat (palm stearin) on cholesterol and bile acid metabolism, male Syrian golden hamsters were fed semipurified diets containing 5% fat and 0.2% cholesterol for 5 weeks. To test whether oil refining would have an impact on the cholesterol-lowering potential, unrefined and refined varieties of rapeseed and olive oil were included. After 5 weeks, plasma total cholesterol (TC) was highest with palm stearin (10.0 ± 2.6 mmol/l) while the MUFA- or PUFA-rich fats significantly lowered TC. The lowest TC concentrations were found with refined rapeseed, cold pressed rapeseed and 18:2-rich sunflower oil (6.7 ± 1.2; 7.1 ± 0.7 and 7.1 ± 0.7 mmol/l, respectively), whereas TC was 10–15% higher (not significant) with 18:1-rich sunflower, virgin and refined olive oil. Liver cholesterol concentrations were lowest in hamsters fed palm stearin or 18:2-rich sunflower oil while MUFA-rich fats increased hepatic cholesteryl ester accumulation, especially of cholesteryl oleate. There were no significant differences in the fecal neutral sterol and bile acid excretion. These data demonstrate that MUFA-rich dietary fats, e.g. rapeseed, olive and 18:1-rich sunflower oil, are comparable in their hypocholesterolemic potential and cause similar effects on plasma cholesterol as 18:2-rich sunflower oil in hamsters when the dietary cholesterol intake is moderate.

The effect of high- (hePE) and low- (lePE) esterification pectin and high- (hvGG) and low-(lvGG) viscosity guar gum on plasma, hepatic and biliary lipids and on prevention of cholesterol gallstones was investigated in male golden Syrian hamsters (Mesocricetus auratus). Hamsters were fed on cholesterol-rich (4g/kg), gallstone-inducing diets for 6 weeks. The diets were supplemented with 80g hePE, lePE, hvGG or lvGG/kg or 80g additional cellulose/kg. No significant differences in plasma total cholesterol and triacylglycerol concentrations between hvGG and lvGG and the gallstone-inducing or cellulose-enriched diets were observed. The hePE diet produced a 16% (non-significant) reduction in total plasma cholesterol but significantly decreased the plasma triacylglycerol level by 45%. The lePE diet caused only minor changes in plasma lipids. Hepatic cholesterol concentrations were significantly higher in hamsters fed on hvGG, lvGG, hePE or lePE primarily due to the accumulation of esterified cholesterol. Supersaturated bile samples, with lithogenic indices ranging from 1.6 to 2.0, were determined with all diets. The hePE and lePE diets slightly altered the bile acid profile by increasing glycocholic acid and decreasing taurochenodeoxycholic acid concentrations resulting in a higher cholic: chenodeoxycholic acid ratio. Cholesterol gallstone formation was not substantially inhibited by the two varieties of pectin and guar gum. The hvGG, lvGG, hePE and lePE diets did not alter faecal weight and caused only minor increases in faecal bile acid excretion. In general, the present findings demonstrate that dietary pectins and guar gums had only minor effects on cholesterol metabolism and did not prevent cholesterol gallstone formation in this hamster model. Possible explanations for this lack of a distinct response to pectin and guar gum are discussed.

The lipid-lowering potential of chitin and chitosan (CHI) and their protective effect against cholesterol gallstone formation was investigated by feeding male Golden Syrian hamsters gallstone-inducing diets. Since the physicochemical properties like degree of deacetylation or viscosity are thought to be involved in the hypocholesterolemic action of CHI, two varieties of CHI, a 92% and a 79% deacetylated CHI (CHI92 and CHI79) were tested. Hamsters were fed semipurified, gallstone-inducing diets containing 5% fat, 0.4% cholesterol and 10% cellulose with or without supplements of chitin (8%) or the two CHIs (8% and 4%). After 5 weeks, 8% CHI79 significantly reduced plasma lipids (total cholesterol (TC): 4.5±0.7 vs 10.1±3.9 mmol/L and triglycerides (TG): 2.9±1.5 vs 7.3±3.6 mmol/L compared to the control diet), whereas 8% CHI92 produced only a minor hypocholesterolemic effect (−10%). Feeding 8% CHI92 or CHI79 caused a significant reduction in food intake, body weight gain and liver weight. The adverse effect on food intake and growth was lessened by feeding 4% CHI92 or CHI79, but the differences were still significant for CHI92. The supplementation with 4% of both CHIs resulted in a significant lowering of plasma cholesterol with a reduction in TC of 38% with CHI92 and 32% with CHI79 compared to the control diet. Hepatic cholesterol was significantly decreased with 8% CHI79, whereas 8% CHI92 caused only a negligible reduction. The 4% supplement of CHI92 did not alter cholesterol accumulation in the liver, but hepatic total cholesterol was significantly increased with 4% CHI79. While the 8% supplements of both CHIs completely inhibited cholesterol gallstone formation, 4% CHI92 or CHI79 added to the diet had no preventive effect and a 90% incidence of cholesterol gallstones was observed. 8% chitin produced no apparent effects on plasma, hepatic and biliary lipids. Whereas 8% CHI79 significantly increased the cholate : chenodeoxycholate ratio of gallbladder bile by decreasing particularly taurochenodeoxycholate, 8% CHI92 had no distinct impact on bile acid composition. The 4% supplements of CHI92 or CHI79 did not alter biliary lipids and bile acid distribution. The dried fecal weight was doubled by feeding 8% and 4% of CHI92 or CHI79 compared to the control diet. Whereas the daily excretion of neutral sterols was significantly expanded with the 8% supplements of CHI92 and CHI 79, only CHI79 caused also a 1.9-fold increase in the daily bile acid excretion. The supplementation with 4% of CHI92 or CHI79 did not significantly change fecal excretion of bile acids or neutral sterols although daily excretion of neutral sterols was increased by 20%. These data demonstrate that in hamsters feeding CHI is associated with a reduced food intake and that the cholesterol-lowering effect seems mainly related to an increase in the fecal excretion of neutral sterols.

The impact of microwave cooking on the formation of early Maillard products was investigated and compared with the effect of conventional cooking, using milk as a test system. Experiments were carried out at controlled temperatures of 80°C and 90°C, respectively, at holding times up to 420 min. Furosine, hydroxymethylfurfural (HMF) and lactulose, which are all established indicators to estimate heat damage, were determined. The concentrations of all the heating indicators increased with increasing heating time. For example in the 90°C test series the furosine values rose from 34 mg litre -l (0.5 h) to 94 mg litre -1 (2 h h holding time) in the milk heated by microwaves and from 35 mg litre -1 (0.5 h) to 96 mg litre -1 (2 h) in the conventionally heated milk. None of the reaction products showed significant differences as between the microwave heating and conventional cooking methods.

We aimed to investigate the effects of increased intake of α-linolenic acid (ALA), EPA, or DHA incorporated into a food matrix on the fatty acid composition of erythrocytes and on biomarkers of oxidant/antioxidant status. To this end, a controlled dietary study was conducted in 74 healthy men and women. The participants were randomly assigned to 1 of 3 interventions in which margarines fortified with either 10 weight percent ALA, EPA, or DHA ethyl esters replaced their normal spread for 6 wk. The total intakes of ALA, EPA, and DHA were 4.4, 2.2, and 2.3 g/d, respectively. Consuming EPA increased the erythrocyte proportion of EPA (394%) and the omega-3 index (sum of EPA and DHA, 38%). Consumption of DHA increased erythrocyte DHA (91%), the omega-3 index (98%), and EPA (137%). The omega-3 index increased to a significantly greater extent in the DHA group than in the EPA group. ALA did not increase erythrocyte EPA or the omega-3 index. We found no change in plasma uric acid or antioxidant capacity in any of the groups. Plasma malondialdehyde (MDA) increased with the EPA and DHA interventions. All 3 interventions decreased erythrocyte linoleic acid hydroperoxides but did not affect their MDA concentrations. In conclusion, the intake of both isolated EPA and DHA incorporated into margarine resulted in an enhanced incorporation of EPA and DHA into erythrocytes. Our findings indicate that DHA is quantitatively superior to EPA in view of the EPA+DHA tissue incorporation and also that 4 g/d ALA is not sufficient to increase the omega-3 index over a 6-wk period.

To evaluate further the reported degradation of furosine during gas chromatographic (GC) determination, a set of experiments with different derivatization conditions were carried out, utilizing a pure furosine standard. The results showed that the decomposition of furosine is not a consequence of the GC separation process, but a result of the derivatization procedure applied. Depending on the derivatization conditions, distinct differences in the percentage degradation were observed. Particularly, an incorrect strong drying during the second and third evaporation steps resulted in substantial degradation (up to ca. 21%), suggesting that the isobutyl ester and the heptafluorobutyryl isobutyl ester of furosine are sensitive to dryness. This demonstrates that the GC determination of furosine as a heptafluorobutyryl isobutyl ester derivative cannot be recommended for routine analytical application. Even under optimum derivatization conditions, degradation in the range 3–5% cannot be completely avoided.

To determine Ne -carboxymethyllysine (CML) in foods a RP-HPLC method after derivatisation with o -phthaldialdehyde was developed. To prevent an overestimation of the CML values by the formation of CML from Amadori products during hydrolysis a borohydride reduction precedes the hydrolysis. A comparison of the determination with and without reduction shows that during hydrolysis 2–12 times more CML than originally present can be formed. With the analytical conditions described in this paper it is possible to obtain measurable amounts of this trace substance in spite of the much higher values for other amino acids. The CML contents in selected processed food items varied between 11 mg in a preparation from mixed cereals for infants to 408 mg/kg protein in a processed malt product. CML is suitable as indicator of heat damage in processed or stored foods, being more stable than the Amadori compounds determined, e.g. in form of furosine.

Zur Untersuchung der Bildung vonNe-Carboxymethyllysin (CML) in Lebensmitteln wurden Modellversuche mit aquimolaren Mischungen aus Lysin und Glucose (88 Vol.-% Wassergehalt, 100 °C Erhitzungstemperatur) durchgefuhrt. In den Modellmischungen wurde der Einflus verschiedener Reaktionsbedingungen (Hydrolyse, pH-Wert) sowie von Zusatzstoffen (Eisen, Phosphat und Nitrit) auf die CML-Bildung untersucht. Die CML-Analysen erfolgten mittels einer RPHPLC-Methode nach Vorsaulenderivatisierung mito-Phthaldialdehyd. Ein Problem der CML-Bestimmung liegt darin, das bei der zur Aminosaurenbestimmung in Lebensmitteln ublichen Saurehydrolyse CML ause-Fructoselysin gebildet werden kann. In den Modellmischungen wurden ohne Hydrolyse nur 8–21% der Gehalte in den hydrolysierten Modellen ermittelt. Da bei Lebensmitteln auf eine Hydrolyse nicht verzichtet werden kann, mus durch eine vorherige Reduktion des Fructoselysins mittels Natriumborhydrid verhindert werden, das wahrend der Hydrolyse eine Weiterreaktion zu CML stattfindet und es zu Fehlinterpretationen uber den wahren CML-Gehalt kommt. Die Reduktion des Fructoselysins kann durch eine Furosinbestimmung kontrolliert werden. Der pH-Wert der Modellmischung ubte einen betrachtlichen Einflus auf die CML-Bildung aus. Bei pH 4 wurden 70 mg, bei pH 7 370 mg und bei pH 9 3170 mg CML/kg Lysin ermittelt. Mit steigenden Konzentrationen bewirkten Eisen(III) sehr deutliche, Phosphat und Nitrit etwas geringere Steigerungen der CMLBildung. Eine Erklarung fur diese Ergebnisse konnte in einer oxidationsfordernden Wirkung auf das Reaktionssystem Fructoselysin/CML liegen.

Scope:trans-Resveratrol has been shown to improve insulin sensitivity and to enhance cellular glucose uptake. Evidence from recent studies indicates that these effects depend on SIRT1-pathways. Methods and results: Since ingestion of resveratrol leads to the presence of resveratrol and resveratrol metabolites in the body, we aimed at investigating (i) whether a daily dose of 300 mg resveratrol/kg body weight in healthy male Wistar rats for a period of 8 wk affects the selected parameters of glucose and lipid metabolism and (ii) whether the resulting plasma concentrations of resveratrol metabolites were effective in modulating SIRT1 expression. The dietary dose was based on the results from preceding toxicity studies. The results from the feeding experiment revealed plasma concentrations of resveratrol and its metabolites below 1 μmol/L and showed that fasting glucose and insulin levels were decreased by 35 and 41%, respectively, in the resveratrol group compared with controls. Insulin sensitivity was enhanced by 70%, whereas liver SIRT1 protein expression was not affected. Treatment of HepG2 cells with 10 μM resveratrol (1.49-fold) or its diglucuronides (1.21-fold) increased SIRT1 expression. Conclusion: These results suggest that the improved insulin sensitivity after dietary administration of 300 mg resveratrol/kg body weight does not involve increased protein expression of SIRT1.

Since a furosine standard became available only recently, arginine was used as the external standard in ion-exchange chromatography (IEC) and 2-acetylfuran in a recently proposed HPLC method. Using the pure furosine standard it was subsequently shown that both procedures produced inexact furosine values. With IEC a substantial decrease in the recovery of furosine of up to 30% was found depending on the elution conditions of pH and temperature that were applied. On the other hand, the use of 2-acetylfuran with HPLC led to an overestimation of furosine content of about 20%. However, correct furosine values were obtained using an IEC clution buffer of pH 4.00 at a temperature of 60°C as was shown by comparison with the HPLC method also based on the furosine standard. These results allow correction of the data obtained in earlier studies and more accurate determination of furosine values in future.