TY - JOUR A1 - Ali, Mostafa A1 - Homann, Thomas A1 - Khalil, Mahmoud A1 - Kruse, Hans-Peter A1 - Rawel, Harshadrai Manilal T1 - Milk whey protein modification by coffee-specific phenolics effect on structural and functional properties JF - Journal of agricultural and food chemistry : a publication of the American Chemical Society N2 - A suitable vehicle for integration of bioactive plant constituents is proposed. It involves modification of proteins using phenolics and applying these for protection of labile constituents. It dissects the noncovalent and covalent interactions of beta-lactoglobulin with coffee-specific phenolics. Alkaline and polyphenol oxidase modulated covalent reactions were compared. Tryptic digestion combined with MALDI-TOF-MS provided tentative allocation of the modification type and site in the protein, and an in silico modeling of modified beta-lactoglobulin is proposed. The modification delivers proteins with enhanced antioxidative properties. Changed structural properties and differences in solubility, surface hydrophobicity, and emulsification were observed. The polyphenol oxidase modulated reaction provides a modified beta-lactoglobulin with a high antioxidative power, is thermally more stable, requires less energy to unfold, and, when emulsified with lutein esters, exhibits their higher stability against UV light. Thus, adaptation of this modification provides an innovative approach for functionalizing proteins and their uses in the food industry. KW - coffee phenolic compounds KW - whey proteins KW - antioxidants KW - protein-phenol interactions KW - modeling KW - functionalizing proteins Y1 - 2013 U6 - https://doi.org/10.1021/jf402221m SN - 0021-8561 VL - 61 IS - 28 SP - 6911 EP - 6920 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Ali, Mostafa A1 - Homann, Thomas A1 - Kreisel, Janka A1 - Khalil, Mahmoud A1 - Puhlmann, Ralf A1 - Kruse, Hans-Peter A1 - Rawel, Harshadrai Manilal T1 - Characterization and modeling of the interactions between coffee storage proteins and phenolic compounds JF - Journal of agricultural and food chemistry : a publication of the American Chemical Society N2 - This study addresses the interactions of coffee storage proteins with coffee-specific phenolic compounds. Protein profiles, of Coffea arabica and Coffea canephora (var robusta) were compared. Major Phenolic compounds were extracted and analyzed with appropriate methods. The polyphenol-protein interactions during protein extraction have been addressed by different analytical setups [reversed-phase high-performance liquid chromatography (RP-HPLC), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS), and Trolox equivalent antioxidant capacity (TEAC) assays], with focus directed toward identification of covalent adduct formation. The results indicate that C. arabica proteins are more susceptible to these interactions and the polyphenol oxidase activity seems to be a crucial factor for the formation of these addition products. A tentative allocation of the modification type and site in the protein has been attempted. Thus, the first available in silico modeling of modified coffee proteins is reported. The extent of these modifications may contribute to the structure and function of "coffee melanoidins" and are discussed in the context of coffee flavor formation. KW - Coffee beans KW - storage proteins KW - phenolic compounds KW - antioxidants KW - protein-phenol interactions KW - modeling Y1 - 2012 U6 - https://doi.org/10.1021/jf303372a SN - 0021-8561 VL - 60 IS - 46 SP - 11601 EP - 11608 PB - American Chemical Society CY - Washington ER - TY - GEN A1 - Baldermann, Susanne A1 - Homann, Thomas A1 - Neugart, Susanne A1 - Chmielewski, Frank M. A1 - Götz, Klaus-Peter A1 - Gödeke, Kristin A1 - Huschek, Gerd A1 - Morlock, Gertrud E. A1 - Rawel, Harshadrai Manilal T1 - Selected Plant Metabolites Involved in Oxidation-Reduction Processes during Bud Dormancy and Ontogenetic Development in Sweet Cherry Buds (Prunus avium L.) T2 - Molecules N2 - Many biochemical processes are involved in regulating the consecutive transition of different phases of dormancy in sweet cherry buds. An evaluation based on a metabolic approach has, as yet, only been partly addressed. The aim of this work, therefore, was to determine which plant metabolites could serve as biomarkers for the different transitions in sweet cherry buds. The focus here was on those metabolites involved in oxidation-reduction processes during bud dormancy, as determined by targeted and untargeted mass spectrometry-based methods. The metabolites addressed included phenolic compounds, ascorbate/dehydroascorbate, reducing sugars, carotenoids and chlorophylls. The results demonstrate that the content of phenolic compounds decrease until the end of endodormancy. After a long period of constancy until the end of ecodormancy, a final phase of further decrease followed up to the phenophase open cluster. The main phenolic compounds were caffeoylquinic acids, coumaroylquinic acids and catechins, as well as quercetin and kaempferol derivatives. The data also support the protective role of ascorbate and glutathione in the para- and endodormancy phases. Consistent trends in the content of reducing sugars can be elucidated for the different phenophases of dormancy, too. The untargeted approach with principle component analysis (PCA) clearly differentiates the different timings of dormancy giving further valuable information. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 467 KW - dormancy KW - redox-metabolites KW - phenolics KW - ascorbate KW - anti-oxidative capacity KW - Prunus avium L. KW - flower buds Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-417442 ER - TY - JOUR A1 - Baldermann, Susanne A1 - Homann, Thomas A1 - Neugart, Susanne A1 - Chmielewski, Frank M. A1 - Götz, Klaus-Peter A1 - Gödeke, Kristin A1 - Huschek, Gerd A1 - Morlock, Gertrud E. A1 - Rawel, Harshadrai Manilal T1 - Selected Plant Metabolites Involved in Oxidation-Reduction Processes during Bud Dormancy and Ontogenetic Development in Sweet Cherry Buds (Prunus avium L.) JF - Molecules N2 - Many biochemical processes are involved in regulating the consecutive transition of different phases of dormancy in sweet cherry buds. An evaluation based on a metabolic approach has, as yet, only been partly addressed. The aim of this work, therefore, was to determine which plant metabolites could serve as biomarkers for the different transitions in sweet cherry buds. The focus here was on those metabolites involved in oxidation-reduction processes during bud dormancy, as determined by targeted and untargeted mass spectrometry-based methods. The metabolites addressed included phenolic compounds, ascorbate/dehydroascorbate, reducing sugars, carotenoids and chlorophylls. The results demonstrate that the content of phenolic compounds decrease until the end of endodormancy. After a long period of constancy until the end of ecodormancy, a final phase of further decrease followed up to the phenophase open cluster. The main phenolic compounds were caffeoylquinic acids, coumaroylquinic acids and catechins, as well as quercetin and kaempferol derivatives. The data also support the protective role of ascorbate and glutathione in the para- and endodormancy phases. Consistent trends in the content of reducing sugars can be elucidated for the different phenophases of dormancy, too. The untargeted approach with principle component analysis (PCA) clearly differentiates the different timings of dormancy giving further valuable information. KW - dormancy KW - redox-metabolites KW - phenolics KW - ascorbate KW - anti-oxidative capacity KW - Prunus avium L. KW - flower buds Y1 - 2018 U6 - https://doi.org/10.3390/molecules23051197 SN - 1420-3049 VL - 23 IS - 5 SP - 1 EP - 19 PB - Molecular Diversity Preservation International CY - Basel ER - TY - JOUR A1 - Chmielewski, Frank M. A1 - Baldermann, Susanne A1 - Götz, Klaus Peter A1 - Homann, Thomas A1 - Gödeke, Kristin A1 - Schumacher, Fabian A1 - Huschek, Gerd A1 - Rawel, Harshadrai Manilal T1 - Abscisic acid related metabolites in sweet cherry buds (Prunus avium L.) JF - Journal of Horticulture N2 - As our climate changes, plant mechanisms involved for dormancy release become increasingly important for commercial orchards. It is generally believed that abscisic acid (ABA) is a key hormone that responds to various environmental stresses which affects bud dormancy. For this reason, a multi-year study was initiated to obtain data on plant metabolites during winter rest and ontogenetic development in sweet cherry buds (Prunus avium L.). In this paper, we report on metabolites involved in ABA synthesis and catabolism and its effect on bud dormancy in the years 2014/15-2016/17. In previous work, the timings of the different phases of para-, endo-, ecodormancy and ontogenetic development for cherry flower buds of the cultivar ‘Summit’ were determined, based on classical climate chamber experiments and changes in the bud’s water content. Based on these time phases, we focused now on the different aspects of the ABA-metabolism. The results show that there is a continual synthesis of ABA about 5 weeks before leaf fall, and a degradation of ABA during ecodormancy and bud development until the phenological stage ‘open cluster’. This is confirmed by relating the ABA content to that of the total precursor carotenoids, neoxanthin and violaxanthin. The tentative monitoring of individual intermediate metabolites revealed that dihydroxyphaseic acid is the most abundant catabolite of ABA and ABA glucosyl ester is in terms of mass intensity, the most abundant ABA metabolite observed in this study. The results suggest that the direct route for ABA biosynthesis from farnesyl pyrophosphate may also be relevant in cherry flower buds. KW - Dormancy KW - Abscisic acid KW - Synthesis KW - Catabolism KW - Prunus avium L. KW - Flower buds Y1 - 2018 U6 - https://doi.org/10.4172/2376-0354.1000221 SN - 2376-0354 VL - 5 IS - 1 ER - TY - JOUR A1 - Chmielewski, Frank M. A1 - Götz, Klaus-Peter A1 - Homann, Thomas A1 - Rawel, Harshadrai Manilal T1 - Identification of Endodormancy Release for Cherries (Prunus Avium L.) by Abscisic Acid and Sugars JF - Journal of Horticulture N2 - In order to develop reliable and physiologically sound models for the plant development in spring, the date of endodormancy release is always a crucial and mostly unknown model parameter. Until present, classical approaches - such as climate chamber experiments - are used to derive this unknown parameter. In these experiments, progressive plant development or significant changes in bud’s fresh weight or water content are measurable markers for dormancy release. This study presents an alternative approach, which is based on four well-known metabolites. For 5 seasons (2011/12-2015/16), the content of abscisic acid (ABA) and sugars such as fructose, sucrose and glucose in sweet cherry flower buds (cultivar ‘Summit’) were weekly analysed between beginning of October and April. These data allow comparing the annual course of these metabolites with the date of endodormancy release, derived from a classical climate chamber experiment, published in a previous study. Results showed that ABA and sucrose are two important metabolites which can help to identify the date of endodormancy release of sweet cherries. On average, ABA content reached a plateau of 5.65 μg g-1 DW-1 during endodormancy, which was maintained for 3-6 weeks. The significant reduction of the ABA content after this period to 4.41 μg g-1 DW-1 on average during ecodormancy was nearly in agreement with the date of endodormancy release of ‘Summit’ on 28 November (332 DOY). The annual cycle of sucrose, which has a cryoprotective effect during winter, is well comprehensible and showed a close relationship to the annual course of minimum air temperature after leaf fall(r=-0.90). The nearly constant level of sucrose during ecodormancy (21.0 mg g-1 DW-1, 5 yr. mean) did not only allow deriving the date of endodormancy release but can also be helpful to define the beginning of ontogenetic development. KW - Endodormancy KW - Abscisic acid KW - Sucrose KW - Prunus avium L. KW - Flower buds KW - Phenological modelling Y1 - 2017 U6 - https://doi.org/10.4172/2376-0354.1000210 SN - 2376-0354 VL - 4 IS - 3 ER - TY - GEN A1 - Figueroa Campos, Gustavo A. A1 - G. K. T. Kruizenga, Johannes A1 - Sagu Tchewonpi, Sorel A1 - Schwarz, Steffen A1 - Homann, Thomas A1 - Taubert, Andreas A1 - Rawel, Harshadrai T1 - Effect of the Post-Harvest Processing on Protein Modification in Green Coffee Beans by Phenolic Compounds T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The protein fraction, important for coffee cup quality, is modified during post-harvest treatment prior to roasting. Proteins may interact with phenolic compounds, which constitute the major metabolites of coffee, where the processing affects these interactions. This allows the hypothesis that the proteins are denatured and modified via enzymatic and/or redox activation steps. The present study was initiated to encompass changes in the protein fraction. The investigations were limited to major storage protein of green coffee beans. Fourteen Coffea arabica samples from various processing methods and countries were used. Different extraction protocols were compared to maintain the status quo of the protein modification. The extracts contained about 4–8 µg of chlorogenic acid derivatives per mg of extracted protein. High-resolution chromatography with multiple reaction monitoring was used to detect lysine modifications in the coffee protein. Marker peptides were allocated for the storage protein of the coffee beans. Among these, the modified peptides K.FFLANGPQQGGK.E and R.LGGK.T of the α-chain and R.ITTVNSQK.I and K.VFDDEVK.Q of β-chain were detected. Results showed a significant increase (p < 0.05) of modified peptides from wet processed green beans as compared to the dry ones. The present study contributes to a better understanding of the influence of the different processing methods on protein quality and its role in the scope of coffee cup quality and aroma. View Full-Text T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1256 KW - Arabica coffee KW - coffee processing KW - protein modification KW - bound phenolic compounds KW - peptide biomarkers KW - LC-MS/MS Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-557643 SN - 1866-8372 VL - 11 SP - 1 EP - 19 PB - Universitätsverlag Potsdam CY - Potsdam ET - 2 ER - TY - JOUR A1 - Figueroa Campos, Gustavo Adolfo A1 - G. K. T. Kruizenga, Johannes A1 - Sagu Tchewonpi, Sorel A1 - Schwarz, Steffen A1 - Homann, Thomas A1 - Taubert, Andreas A1 - Rawel, Harshadrai Manilal T1 - Effect of the post-harvest processing on protein modification in green coffee beans by phenolic compounds JF - Foods : open access journal N2 - The protein fraction, important for coffee cup quality, is modified during post-harvest treatment prior to roasting. Proteins may interact with phenolic compounds, which constitute the major metabolites of coffee, where the processing affects these interactions. This allows the hypothesis that the proteins are denatured and modified via enzymatic and/or redox activation steps. The present study was initiated to encompass changes in the protein fraction. The investigations were limited to major storage protein of green coffee beans. Fourteen Coffea arabica samples from various processing methods and countries were used. Different extraction protocols were compared to maintain the status quo of the protein modification. The extracts contained about 4–8 µg of chlorogenic acid derivatives per mg of extracted protein. High-resolution chromatography with multiple reaction monitoring was used to detect lysine modifications in the coffee protein. Marker peptides were allocated for the storage protein of the coffee beans. Among these, the modified peptides K.FFLANGPQQGGK.E and R.LGGK.T of the α-chain and R.ITTVNSQK.I and K.VFDDEVK.Q of β-chain were detected. Results showed a significant increase (p < 0.05) of modified peptides from wet processed green beans as compared to the dry ones. The present study contributes to a better understanding of the influence of the different processing methods on protein quality and its role in the scope of coffee cup quality and aroma. View Full-Text KW - Arabica coffee KW - coffee processing KW - protein modification KW - bound phenolic compounds KW - peptide biomarkers KW - LC-MS/MS Y1 - 2022 U6 - https://doi.org/10.3390/foods11020159 SN - 2304-8158 VL - 11 PB - MDPI CY - Basel, Schweiz ET - 2 ER - TY - JOUR A1 - Gerecke, Christian A1 - Schumacher, Fabian A1 - Berndzen, Alide A1 - Homann, Thomas A1 - Kleuser, Burkhard T1 - Vitamin C in combination with inhibition of mutant IDH1 synergistically activates TET enzymes and epigenetically modulates gene silencing in colon cancer cells JF - Epigenetics : the official journal of the DNA Methylation Society N2 - Mutations in the enzyme isocitrate dehydrogenase 1 (IDH1) lead to metabolic alterations and a sustained formation of 2-hydroxyglutarate (2-HG). 2-HG is an oncometabolite as it inhibits the activity of alpha-ketoglutarate-dependent dioxygenases such as ten-eleven translocation (TET) enzymes. Inhibitors of mutant IDH enzymes, like ML309, are currently tested in order to lower the levels of 2-HG. Vitamin C (VC) is an inducer of TET enzymes. To test a new therapeutic avenue of synergistic effects, the anti-neoplastic activity of inhibition of mutant IDH1 via ML309 in the presence of VC was investigated in the colon cancer cell line HCT116 IDH1(R132H/+) (harbouring a mutated IDH1 allele) and the parental cells HCT116 IDH1(+/+) (wild type IDH1). Measurement of the oncometabolite indicated a 56-fold higher content of 2-HG in mutated cells compared to wild type cells. A significant reduction of 2-HG was observed in mutated cells after treatment with ML 309, whereas VC produced only minimally changes of the oncometabolite. However, combinatorial treatment with both, ML309 and VC, in mutated cells induced pronounced reduction of 2-HG leading to levels comparable to those in wild type cells. The decreased level of 2-HG in mutated cells after combinatorial treatment was accompanied by an enhanced global DNA hydroxymethylation and an increased gene expression of certain tumour suppressors. Moreover, mutated cells showed an increased percentage of apoptotic cells after treatment with non-cytotoxic concentrations of ML309 and VC. These results suggest that combinatorial therapy is of interest for further investigation to rescue TET activity and treatment of IDH1/2 mutated cancers. KW - Vitamin C KW - epigenetics KW - IDH1 KW - TET KW - cancer cells Y1 - 2019 U6 - https://doi.org/10.1080/15592294.2019.1666652 SN - 1559-2294 SN - 1559-2308 VL - 15 IS - 3 SP - 307 EP - 322 PB - Taylor & Francis Group CY - Philadelphia ER - TY - JOUR A1 - Goetz, Klaus-Peter A1 - Chmielewski, Frank M. A1 - Goedeke, Kristin A1 - Wolf, Kristine A1 - Jander, Elisabeth A1 - Sievers, Steven A1 - Homann, Thomas A1 - Huschek, Gerd A1 - Rawel, Harshadrai Manilal T1 - Assessment of amino acids during winter rest and ontogenetic development in sweet cherry buds (Prunus avium. L.) JF - Scientia horticulturae : an international journal sponsored by the International Society for Horticultural Science N2 - This study examined changes in sweet cherry buds of ‘Summit’ cultivar in four seasons (2011/12–2014/15) with respect to the nitrogen (N) content and the profile of eight free amino acids (asparagine (Asn), aspartic acid (Asp), isoleucine (Ile), glutamine (Gln), glutamic acid (Glu), arginine (Arg), alanine (Ala), histidine (His)). The presented results are to our knowledge the first under natural conditions in fruit tree orchards with a high temporal resolution from the dormant stage until cluster development. The N content in the buds from October, during endo- and ecodormancy until the beginning of ontogenetic development was a relatively stable parameter in each of the four seasons. The N accumulation into the buds began after ‘swollen bud’ and significant differences were visible at ‘green tip’ with an N content of 3.24, 3.12, 3.08, 2.40 which increased markedly to the mean of ‘tight’ and ‘open cluster’ by 3.77%, 3.78%, 3.44% and 3.10% in 2012–2015, respectively. In the buds, levels of asparagine were higher (up to 44 mg g−1 DW−1) than aspartic acid (up to 2 mg g−1 DW−1) and aspartic acid higher than isoleucine (up to 0.83 mg g−1 DW−1). Levels of glutamine were higher (up to 25 mg g−1 DW−1) than glutamic acid (up to 20 mg g−1 DW−1). The course of the arginine content was higher in 2011/12 compared to 2012/13, 2013/14 and 2014/15 which showed only slight differences. The alanine content in the buds was denoted in the four seasons only by relatively minor changes. The histidine content was higher in 2011/12 and 2012/13 compared to 2013/14 and 2014/15 which showed a comparable pattern. For 6 amino acids (Asn, Asp, Ile, Glu, Arg, Ala), the highest content was observed in 2012/13, the warmest period between swollen bud and open cluster. However in 2014/15, the season with the lowest mean temperature of 8.8 °C, only the content of Gln was the lowest. It was not possible to explain any seasonal differences in the amino acid content by environmental factors (air temperature) on the basis of few seasons. From none of the measured free amino acids could a clear determination of the date of endodormancy release (t1) or the beginning of the ontogenetic development (t1*) be derived. Therefore, these amino acids are no suitable markers to improve phenological models for the beginning of cherry blossom. KW - Amino acids KW - Flower buds KW - Prunus avium L. KW - Dormancy KW - Ontogenetic development Y1 - 2017 U6 - https://doi.org/10.1016/j.scienta.2017.05.001 SN - 0304-4238 SN - 1879-1018 VL - 222 SP - 102 EP - 110 PB - Elsevier CY - Amsterdam ER -