TY - JOUR A1 - Rawel, Harshadrai Manilal A1 - Frey, Simone K. A1 - Meidtner, Karina A1 - Kroll, Jürgen A1 - Schweigert, Florian J. T1 - Determining the binding affinities of phenolic compounds to proteins by quenching of the intrinsic tryptophan fluorescence JF - Molecular nutrition & food research : bioactivity, chemistry, immunology, microbiology, safety, technology N2 - The noncovalent binding of selected phenolic compounds (chlorogenic-, ferutic-, gallic acid, quercetin, rutin, and isoquercetin) to proteins (HSA, BSA, soy glycinin, and lysozyme) was studied by an indirect method applying the quenching of intrinsic tryptophan fluorescence. From the data obtained, the binding constants were calculated by nonlinear regression (one site binding; y = Bx/k + x). It has been reported that tannins inhibit human salivary amylase and that these complexes may reduce the development of cariogenic plaques. Further, amylase contains two tryptophan residues in its active site. Therefore, in a second part of the study involving 31 human subjects, evidence was sought for noncovalent interactions between the phenols of green tea and saliva proteins as measured by the fluorescence intensity. Amylase activity was determined before and after the addition of green tea to saliva of 31 subjects. Forty percent of the subjects showed an increase in amylase activity contrary to studies reporting only a decrease in activity. The interactions of tannin with amylase result in a decrease of its activity. It still remains to be elucidated why amylase does not react uniformly under conditions of applying green tea to saliva. Further, in terms of using phenols as caries inhibitors this finding should be of importance. KW - amylase activity KW - green tea phenols KW - protein-phenol binding KW - saliva proteins KW - tryptophan quenching Y1 - 2006 U6 - https://doi.org/10.1002/mnfr.200600013 SN - 1613-4125 VL - 50 IS - 8 SP - 705 EP - 713 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Rohn, Sascha A1 - Petzke, Klaus-Jürgen A1 - Rawel, Harshadrai Manilal A1 - Kroll, Jürgen T1 - Reactions of chlorogenic acid and quercetin with a soy protein isolate - Influence on the in vivo food protein quality in rats JF - Molecular nutrition & food research : bioactivity, chemistry, immunology, microbiology, safety, technology N2 - Plant phenolic compounds are known to interact with proteins producing changes in the food (e.g., biological value (BV), color, taste). Therefore, the in vivo relevance, especially, of covalent phenolprotein reactions on protein quality was studied in a rat bioassay. The rats were fed protein derivatives at a 10% protein level. Soy proteins were derivatized with chlorogenic acid and quercetin (derivatization levels: 0.056 and 0.28 mmol phenolic compound/gram protein). Analysis of nitrogen in diets, urine, and fecal samples as well as the distribution of amino acids were determined. Depending on the degree of derivatization, the rats fed with soy protein derivatives showed an increased excretion of fecal and urinary nitrogen. As a result, true nitrogen digestibility, BV, and net protein utilization were adversely affected. Protein digestibility corrected amino acid score was decreased for lysine, tryptophan, and sulfur containing amino acids. KW - amino acid score KW - plant phenolic compounds KW - protein derivatization KW - protein digestibility KW - soy protein Y1 - 2006 U6 - https://doi.org/10.1002/mnfr.200600043 SN - 1613-4125 VL - 50 SP - 696 EP - 704 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Eggert, Kai A1 - Rawel, Harshadrai Manilal A1 - Nikfardjam, Martin S. Pour A1 - Kroll, Jürgen T1 - Interactions between lysozyme and wine components JF - Deutsche Lebensmittel-Rundschau : DLR N2 - The addition of lysozyme amounting to 1000 mg/l wine does neither effect its total phenol content (Folin-Ciocalteu-Method), nor wine colour (measured by extinction at 512 nm) nor its antioxidative capacity (TEAC-Assay). No covalent binding of wine phenols to the enzyme was observed during lysozyme addition, although non-covalent interactions are possible. Lysozyme activity is not influenced by the presence of malvidin-3-glucoside and resveratrol in model experiments, whereas pH and ethanol content produce a corresponding alteration in lysozyme activity. With regard to red wine, a significant effect was noted in the presence of wine components. KW - lysozyme KW - red wine KW - total phenol content KW - colour KW - antioxidative capacity KW - lysozyme activity Y1 - 2006 SN - 0012-0413 VL - 102 IS - 10 SP - 472 EP - 478 PB - Behr CY - Stuttgart ER - TY - JOUR A1 - Grott, Saskia A1 - Peter, Martin G. A1 - Linker, Torsten A1 - Sefkow, Michael A1 - Kroll, Jürgen A1 - Koetz, Joachim A1 - Laschewsky, André A1 - Lokatis, Siegfried A1 - Rheinberg, Falko A1 - Manig, Yvette T1 - Portal = Chemie: Werkstoffe, Wirkstoffe, Lebensvorgänge BT - Die Potsdamer Universitätszeitung N2 - Aus dem Inhalt: - Chemie: Werkstoffe, Wirkstoffe, Lebensvorgänge - Institut für Kirchenrecht gegründet - Computerlinguisten erstellen digitales Wörterbuch - Vom Spaß am Graffiti-Sprayen T3 - Portal: Das Potsdamer Universitätsmagazin - 01-02/2003 Y1 - 2003 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-439713 SN - 1618-6893 IS - 01-02/2003 ER - TY - JOUR A1 - Kroll, Jürgen A1 - Rawel, Harshadrai Manilal T1 - Die Sojabohne : Inhalsstoffe und deren Lebensmittelchemische und ernährungsphysiologische Bedeutung N2 - The soy bean contains besides comparatively large amounts of nutritionally and physiologically valuable proteins and lipids, also a series of other minor components termed as secondary plant metabolites. In this respect most of the research focus has been directed to the group of isoflavones. Epidemiological studies as well as model and animal experiments document that the consumption of soy products/-components is accompanied by many postive physiological effects, which are discussed shortly in this paper Y1 - 2006 SN - 0012-0431 ER - TY - BOOK A1 - Johnsen, Dieter A1 - Kroll, Jürgen A1 - Lange, Reinhard ED - Berndt, Klaus-Peter ED - Schäfer, Erich T1 - Ernährung - Umwelt - Gesundheit : Teil 1 T3 - Studienmaterialien des Weiterbildenden Studiums Umweltschutz für Bildung und Hauswirtschaft Y1 - 1993 SN - 3-929757-17-6 PB - Univ. Potsdam CY - Potsdam ER - TY - JOUR A1 - Kroll, Jürgen A1 - Noack, Jutta A1 - Rawel, Harshadrai Manilal A1 - Kröck, Regina A1 - Proll, Jürgen T1 - Chemical reactions of benzyl isothio cyanate with egg-white protein fractions Y1 - 1994 ER - TY - JOUR A1 - Kroll, Jürgen A1 - Jancke, Harald J. T1 - Reaktionen von Benzyl-ITC mit Glutathion : NMR-spektroskopische Untersuchungen Y1 - 1994 ER - TY - JOUR A1 - Kroll, Jürgen A1 - Rawel, Harshadrai Manilal A1 - Kröck, Regina A1 - Proll, Jürgen A1 - Schnaak, W. T1 - Interactions of Isothiocyanates with egg white proteins Y1 - 1994 ER - TY - JOUR A1 - Kroll, Jürgen A1 - Helle, N. T1 - Mechanochemischer Abbau von Proteinen : ESR - spektroskopische Untersuchungen Y1 - 1994 ER -