TY - JOUR A1 - Kruse, Hans-Peter A1 - Heydenreich, Matthias A1 - Engst, W. A1 - Schilde, Uwe A1 - Kroll, Jürgen T1 - The identification of 1,3-oxazolidine-2-thiones and 1,3-thiazolidine-2-thiones from the reaction of glucose with benzyl isothiocyanate N2 - The structure of interaction products resulting from the reaction of unmodified glucose with benzyl isothiocyanate is reported. Prior to their identification, the main products of this reaction were isolated using solid- phase extraction (SPE) as well as preparative HPLC. They were then identified by NMR and MS as 3-benzyl-4-hydroxy-5-(D- arabino-1,2,3,4-tetrahydroxybutyl)- 1,3-oxazolidine-2-thione, 3-benzyl-4-hydroxy-4-hydroxymethyl-5-(D-erythro-1,2,3- trihydroxypropyl)- 1,3-oxazolidine-2-thione, N-benzyl-(D-gluco-4,5-dihydroxy-6-hydroxymethyl-tetrahydropyrano)[2,3-b] oxazolidine-2-thione and 3-benzyl-4-(N-benzyl amino)-5-(D-arabino-1,2,3,4-tetrahydroxybutyl)-1,3-thiazolidine-2-thione . The identity of the last compound was secured by X-ray crystal structure data. (C) 2004 Elsevier Ltd. All rights reserved Y1 - 2005 SN - 0008-6215 ER - TY - JOUR A1 - Rawel, Harshadrai Manilal A1 - Rohn, Sascha A1 - Kroll, Jürgen A1 - Schweigert, Florian J. T1 - Surface enhanced laser desorptions ionization-time of flight-mass spectrometry analysis in complex food and biological systems Y1 - 2005 ER - TY - JOUR A1 - Rawel, Harshadrai Manilal A1 - Rohn, Sascha A1 - Kruse, Hans-Peter A1 - Kroll, Jürgen T1 - Structural changes induced in bovine serum albumin by covalent attachment of chlorogenic acid N2 - Bovine serum albumin (BSA) was modifed by covalent attachment of chlorogenic acid using different concentrations at pH 9. The derivatization was accompanied by a reduction of lysine, cysteine and tryptophan residues. The isoelectric points were shifted to lower pH values and formation of high molecular weight fractions was noted. The structural changes were studied using circular dichroism, differential scanning calorimetry (DSC), intrinsic fluorescence, and binding of anilinonaphthalenesulfonic acid. The results showed that the content of alpha-helix decreased with a parallel increase in unordered structures with higher degrees of derivatization. DSC revealed a decrease in both denaturation temperature and enthalpy. Surface hydrophobicity declined, indicating that hydrophilic regions were exposed on the molecular surface. Proteolytic digestion showed that, at a lower degree of derivatization,the tryptic degradation was most adversely effected, whereas the peptic digestion declined with increasing modification. A trypsin inhibitory effect of the breakdown products released from derivatized BSA was also observed. Y1 - 2002 ER - TY - JOUR A1 - Rawel, Harshadrai Manilal A1 - Kroll, Jürgen T1 - Some aspects of reactions of benzyl isothiocyanate with bovine sarcoplasmic proteins Y1 - 1995 ER - TY - JOUR A1 - Rohn, Sascha A1 - Rawel, Harshadrai Manilal A1 - Rober, M. A1 - Kroll, Jürgen T1 - Reactions with phenolic substances can induce changes in some physico-chemical properties and activities of bromelain - the consequences for supplementary food products N2 - Bromelain was allowed to react with phenolic compounds. The activity and selected physico-chemical properties of the resulting derivatives were characterized. In vitro experiments showed that the proteolytic activity of bromelain was inhibited. Bromelain also serves as a food protein, because food stuffs based on pineapple contain relatively high concentrations of bromelain. In vitro digestion of bromelain derivatives with the main proteolytic enzymes of the gastrointestinal tract was also adversely affected. A covalent attachment of the phenolic compounds was identified at the tryptophan, free amino (lysines and N-terminal) and thiol groups of bromelain. A decrease in solubility of the derivatives was observed. The isoelectric point was shifted to lower pH values and high molecular weight fractions were identified. All effects observed depended on the reactivity of the phenolic substances. Two supplementary food products containing both bromelain and quercetin were also tested in terms of their proteolytic activity and digestibility Y1 - 2005 SN - 0950-5423 ER - TY - JOUR A1 - Rawel, Harshadrai Manilal A1 - Rohn, Sascha A1 - Kroll, Jürgen T1 - Reactions of selected secondary plant metabolites (glucosinolates and phenols) with food proteins and enzymes - Influence on physicochemical properties, enzyme activity and proteolytic dagradation Y1 - 2000 ER - TY - JOUR A1 - Kroll, Jürgen A1 - Rawel, Harshadrai Manilal T1 - Reactions of plant phenols with myoglobin : influence of chemical structure of the phenolic compounds Y1 - 2001 ER - TY - JOUR A1 - Kroll, Jürgen A1 - Rawel, Harshadrai Manilal T1 - Reactions of plant phenols with myoglobin : influence of chemical structure of the phenolic compounds Y1 - 2000 ER - TY - JOUR A1 - Kroll, Jürgen A1 - Rawel, Harshadrai Manilal A1 - Rohn, Sascha T1 - Reactions of plant phenolics with food proteins and enzymes under special consideration of covalent bonds : a Review Y1 - 2003 ER - TY - JOUR A1 - Rawel, Harshadrai Manilal A1 - Kroll, Jürgen A1 - Rohn, Sascha T1 - Reactions of phenol substances with lysozyme - physicochemical characterisation and proteolytic digestion of the derivatives Y1 - 2000 ER - TY - JOUR A1 - Rawel, Harshadrai Manilal A1 - Kroll, Jürgen A1 - Schröder, Insa Sigrid T1 - Reactions of isothiocyanates with food proteins : influence on enzyme activity and degradation Y1 - 1998 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 - Rawel, Harshadrai Manilal A1 - Kroll, Jürgen A1 - Haebel, Sophie A1 - Peter, Martin G. T1 - Reactions of a glucosinolate breakdown product (benzyl-isothiocyanate) with myoglobin Y1 - 1998 ER - TY - JOUR A1 - Rawel, Harshadrai Manilal A1 - Kroll, Jürgen A1 - Riese, B. T1 - Reaction of chlorogenic acid with lysozyme : physicochemical characterization and proteolytic digestion of the derivatives Y1 - 2000 ER - TY - JOUR A1 - Kroll, Jürgen A1 - Rawel, Harshadrai Manilal A1 - Seidelmann, N. T1 - Physicochemical properties and susceptibility to proteolytic digestionof myoglobin-phenol derivatives Y1 - 2000 ER - TY - JOUR A1 - Rawel, Harshadrai Manilal A1 - Kroll, Jürgen A1 - Riese-Schneider, Brigitte A1 - Haebel, Sophie T1 - Physicochemical and enzymatic properties of Benzyl-Isothiocyanate derivatized proteinases Y1 - 1998 ER - TY - JOUR A1 - Rawel, Harshadrai Manilal A1 - Kroll, Jürgen A1 - Hohl, U. C. T1 - Model studies on reactions of plant phenols with whey proteins Y1 - 2001 ER - TY - JOUR A1 - Kroll, Jürgen A1 - Rawel, Harshadrai Manilal A1 - Kröck, Regina T1 - Microwave digestion of proteins Y1 - 1998 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 - Rawel, Harshadrai Manilal A1 - Rohn, Sascha A1 - Czajka, Dörte T1 - Interactions of glycinin with plant phenols : influence on chemical properties and proteolytic degradation of the proteins N2 - Soya glycinin was derivatized with different phenolic substances (caffeic-, chlorogenic-, gallic acid and quercetin). The protein derivatives formed have been characterized in terms of their properties where they showed changes in the content of free epsilon-amino groups, tryptophan and thiol groups. The derivatives have also been characterized in terms of their solubility at different pH-values to document the influence on the functional properties. Another objective of this paper was to demonstrate the influence on the digestibility of the proteins with one of the main enzymes of the gastro-intestinal tract (pancreatin) on the basis of in vitro experiments after derivatization with phenolic substances. The enzymatic digestion of the derivatized proteins was promoted. Y1 - 2001 UR - http://www3.interscience.wiley.com/cgi-bin/abstract/85513730 ER -