@misc{SaguTchewonpiZimmermannLandgraeberetal.2020,
  author    = {Sagu Tchewonpi, Sorel and Zimmermann, Lynn and Landgr{\"a}ber, Eva and Homann, Thomas and Huschek, Gerd and {\"O}zpinar, Haydar and Schweigert, Florian J. and Rawel, Harshadrai Manilal},
  title     = {Comprehensive Characterization and Relative Quantification of α-Amylase/Trypsin Inhibitors from Wheat Cultivars by Targeted HPLC-MS/MS},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {1028},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-48611},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-486118},
  pages     = {27},
  year      = {2020},
  abstract  = {The α-amylase/trypsin inhibitors (ATIs) are discussed as being responsible for non-celiac wheat sensitivity (NCWS), besides being known as allergenic components for baker's asthma. Different approaches for characterization and quantification including proteomics-based methods for wheat ATIs have been documented. In these studies generally the major ATIs have been addressed. The challenge of current study was then to develop a more comprehensive workflow encompassing all reviewed wheat-ATI entries in UniProt database. To substantially test proof of concept, 46 German and Turkish wheat samples were used. Two extractions systems based on chloroform/methanol mixture (CM) and under buffered denaturing conditions were evaluated. Three aspects were optimized, tryptic digestion, chromatographic separation, and targeted tandem mass spectrometric analysis (HPLC-MS/MS). Preliminary characterization with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) documented the purity of the extracted ATIs with CM mixture and the amylase (60-80\%)/trypsin (10-20\%) inhibition demonstrated the bifunctional activity of ATIs. Thirteen (individual/common) biomarkers were established. Major ATIs (7-34\%) were differently represented in samples. Finally, to our knowledge, the proposed HPLC-MS/MS method allowed for the first time so far the analysis of all 14 reviewed wheat ATI entries reported.},
  language  = {en}
}
@misc{RawelHuschekSaguTchewonpietal.2019,
  author    = {Rawel, Harshadrai Manilal and Huschek, Gerd and Sagu Tchewonpi, Sorel and Homann, Thomas},
  title     = {Cocoa Bean Proteins-Characterization, Changes and Modifications due to Ripening and Post-Harvest Processing},
  series = {Nutrients},
  volume    = {11},
  journal   = {Nutrients},
  number    = {2},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2072-6643},
  doi       = {10.3390/nu11020428},
  pages     = {20},
  year      = {2019},
  abstract  = {The protein fractions of cocoa have been implicated influencing both the bioactive potential and sensory properties of cocoa and cocoa products. The objective of the present review is to show the impact of different stages of cultivation and processing with regard to the changes induced in the protein fractions. Special focus has been laid on the major seed storage proteins throughout the different stages of processing. The study starts with classical introduction of the extraction and the characterization methods used, while addressing classification approaches of cocoa proteins evolved during the timeline. The changes in protein composition during ripening and maturation of cocoa seeds, together with the possible modifications during the post-harvest processing (fermentation, drying, and roasting), have been documented. Finally, the bioactive potential arising directly or indirectly from cocoa proteins has been elucidated. The state of the art suggests that exploration of other potentially bioactive components in cocoa needs to be undertaken, while considering the complexity of reaction products occurring during the roasting phase of the post-harvest processing. Finally, the utilization of partially processed cocoa beans (e.g., fermented, conciliatory thermal treatment) can be recommended, providing a large reservoir of bioactive potentials arising from the protein components that could be instrumented in functionalizing foods.},
  language  = {en}
}
@article{RawelHuschekSaguTchewonpietal.2019,
  author    = {Rawel, Harshadrai Manilal and Huschek, Gerd and Sagu Tchewonpi, Sorel and Homann, Thomas},
  title     = {Cocoa Bean Proteins},
  series = {Nutrients},
  volume    = {11},
  journal   = {Nutrients},
  number    = {2},
  publisher = {Molecular Diversity Preservation International},
  address   = {Basel},
  issn      = {2072-6643},
  doi       = {10.3390/nu11020428},
  pages     = {20},
  year      = {2019},
  abstract  = {The protein fractions of cocoa have been implicated influencing both the bioactive potential and sensory properties of cocoa and cocoa products. The objective of the present review is to show the impact of different stages of cultivation and processing with regard to the changes induced in the protein fractions. Special focus has been laid on the major seed storage proteins throughout the different stages of processing. The study starts with classical introduction of the extraction and the characterization methods used, while addressing classification approaches of cocoa proteins evolved during the timeline. The changes in protein composition during ripening and maturation of cocoa seeds, together with the possible modifications during the post-harvest processing (fermentation, drying, and roasting), have been documented. Finally, the bioactive potential arising directly or indirectly from cocoa proteins has been elucidated. The "state of the art" suggests that exploration of other potentially bioactive components in cocoa needs to be undertaken, while considering the complexity of reaction products occurring during the roasting phase of the post-harvest processing. Finally, the utilization of partially processed cocoa beans (e.g., fermented, conciliatory thermal treatment) can be recommended, providing a large reservoir of bioactive potentials arising from the protein components that could be instrumented in functionalizing foods.},
  language  = {en}
}
@misc{RawelHuschekSaguTchewonpietal.2019,
  author    = {Rawel, Harshadrai Manilal and Huschek, Gerd and Sagu Tchewonpi, Sorel and Homann, Thomas},
  title     = {Cocoa Bean Proteins},
  series = {Postprints der Universit{\"a}t Potsdam: Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam: Mathematisch-Naturwissenschaftliche Reihe},
  number    = {681},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-42595},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-425953},
  pages     = {20},
  year      = {2019},
  abstract  = {The protein fractions of cocoa have been implicated influencing both the bioactive potential and sensory properties of cocoa and cocoa products. The objective of the present review is to show the impact of different stages of cultivation and processing with regard to the changes induced in the protein fractions. Special focus has been laid on the major seed storage proteins throughout the different stages of processing. The study starts with classical introduction of the extraction and the characterization methods used, while addressing classification approaches of cocoa proteins evolved during the timeline. The changes in protein composition during ripening and maturation of cocoa seeds, together with the possible modifications during the post-harvest processing (fermentation, drying, and roasting), have been documented. Finally, the bioactive potential arising directly or indirectly from cocoa proteins has been elucidated. The "state of the art" suggests that exploration of other potentially bioactive components in cocoa needs to be undertaken, while considering the complexity of reaction products occurring during the roasting phase of the post-harvest processing. Finally, the utilization of partially processed cocoa beans (e.g., fermented, conciliatory thermal treatment) can be recommended, providing a large reservoir of bioactive potentials arising from the protein components that could be instrumented in functionalizing foods.},
  language  = {en}
}
@misc{SaguTchewonpiLandgraeberRackiewiczetal.2020,
  author    = {Sagu Tchewonpi, Sorel and Landgr{\"a}ber, Eva and Rackiewicz, Michal and Huschek, Gerd and Rawel, Harshadrai Manilal},
  title     = {Relative Abundance of Alpha-Amylase/Trypsin Inhibitors in Selected Sorghum Cultivars},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {1068},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-48809},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-488096},
  pages     = {21},
  year      = {2020},
  abstract  = {Sorghum is of growing interest and considered as a safe food for wheat related disorders. Besides the gluten, α-amylase/trypsin-inhibitors (ATIs) have been identified as probable candidates for these disorders. Several studies focused on wheat-ATIs although there is still a lack of data referring to the relative abundance of sorghum-ATIs. The objective of this work was therefore to contribute to the characterization of sorghum ATI profiles by targeted proteomics tools. Fifteen sorghum cultivars from different regions were investigated with raw proteins ranging from 7.9 to 17.0 g/100 g. Ammonium bicarbonate buffer in combination with urea was applied for protein extraction, with concentration from 0.588 ± 0.047 to 4.140 ± 0.066 mg/mL. Corresponding electrophoresis data showed different protein profiles. UniProtKB data base research reveals two sorghum ATIs, P81367 and P81368; both reviewed and a targeted LC-MS/MS method was developed to analyze these. Quantifier peptides ELAAVPSR (P81367) and TYMVR (P81368) were identified and retained as biomarkers for relative quantification. Different reducing and alkylating agents were assessed and combination of tris (2 carboxyethyl) phosphine/iodoacetamide gave the best response. Linearity was demonstrated for the quantifier peptides with standard recovery between 92.2 and 107.6\%. Nine sorghum cultivars presented up to 60 times lower ATI contents as compared to wheat samples. This data suggests that sorghum can effectively be considered as a good alternative to wheat.},
  language  = {en}
}
@misc{SaguTchewonpiHuschekWaldbachBragaetal.2022,
  author    = {Sagu Tchewonpi, Sorel and Huschek, Gerd and Waldbach Braga, Tess and Rackiewicz, Michal and Homann, Thomas and Rawel, Harshadrai Manilal},
  title     = {Design of Experiment (DoE) for Optimization of HPLC Conditions for the Simultaneous Fractionation of Seven α-Amylase/Trypsin Inhibitors from Wheat (Triticum aestivum L.)},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-55928},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-559282},
  pages     = {1 -- 18},
  year      = {2022},
  abstract  = {Wheat alpha-amylase/trypsin inhibitors remain a subject of interest considering the latest findings showing their implication in wheat-related non-celiac sensitivity (NCWS). Understanding their functions in such a disorder is still unclear and for further study, the need for pure ATI molecules is one of the limiting problems. In this work, a simplified approach based on the successive fractionation of ATI extracts by reverse phase and ion exchange chromatography was developed. ATIs were first extracted from wheat flour using a combination of Tris buffer and chloroform/methanol methods. The separation of the extracts on a C18 column generated two main fractions of interest F1 and F2. The response surface methodology with the Doehlert design allowed optimizing the operating parameters of the strong anion exchange chromatography. Finally, the seven major wheat ATIs namely P01083, P17314, P16850, P01085, P16851, P16159, and P83207 were recovered with purity levels (according to the targeted LC-MS/MS analysis) of 98.2 ± 0.7; 98.1 ± 0.8; 97.9 ± 0.5; 95.1 ± 0.8; 98.3 ± 0.4; 96.9 ± 0.5, and 96.2 ± 0.4\%, respectively. MALDI-TOF-MS analysis revealed single peaks in each of the pure fractions and the mass analysis yielded deviations of 0.4, 1.9, 0.1, 0.2, 0.2, 0.9, and 0.1\% between the theoretical and the determined masses of P01083, P17314, P16850, P01085, P16851, P16159, and P83207, respectively. Overall, the study allowed establishing an efficient purification process of the most important wheat ATIs. This paves the way for further in-depth investigation of the ATIs to gain more knowledge related to their involvement in NCWS disease and to allow the absolute quantification in wheat samples.},
  language  = {en}
}
@article{SaguTchewonpiHuschekWaldbachBragaetal.2022,
  author    = {Sagu Tchewonpi, Sorel and Huschek, Gerd and Waldbach Braga, Tess and Rackiewicz, Michal and Homann, Thomas and Rawel, Harshadrai Manilal},
  title     = {Design of Experiment (DoE) for Optimization of HPLC Conditions for the Simultaneous Fractionation of Seven α-Amylase/Trypsin Inhibitors from Wheat (Triticum aestivum L.)},
  series = {Processes : open access journal},
  volume    = {10},
  journal   = {Processes : open access journal},
  edition   = {2},
  publisher = {MDPI},
  address   = {Basel, Schweiz},
  issn      = {2227-9717},
  doi       = {10.3390/pr10020259},
  pages     = {1 -- 18},
  year      = {2022},
  abstract  = {Wheat alpha-amylase/trypsin inhibitors remain a subject of interest considering the latest findings showing their implication in wheat-related non-celiac sensitivity (NCWS). Understanding their functions in such a disorder is still unclear and for further study, the need for pure ATI molecules is one of the limiting problems. In this work, a simplified approach based on the successive fractionation of ATI extracts by reverse phase and ion exchange chromatography was developed. ATIs were first extracted from wheat flour using a combination of Tris buffer and chloroform/methanol methods. The separation of the extracts on a C18 column generated two main fractions of interest F1 and F2. The response surface methodology with the Doehlert design allowed optimizing the operating parameters of the strong anion exchange chromatography. Finally, the seven major wheat ATIs namely P01083, P17314, P16850, P01085, P16851, P16159, and P83207 were recovered with purity levels (according to the targeted LC-MS/MS analysis) of 98.2 ± 0.7; 98.1 ± 0.8; 97.9 ± 0.5; 95.1 ± 0.8; 98.3 ± 0.4; 96.9 ± 0.5, and 96.2 ± 0.4\%, respectively. MALDI-TOF-MS analysis revealed single peaks in each of the pure fractions and the mass analysis yielded deviations of 0.4, 1.9, 0.1, 0.2, 0.2, 0.9, and 0.1\% between the theoretical and the determined masses of P01083, P17314, P16850, P01085, P16851, P16159, and P83207, respectively. Overall, the study allowed establishing an efficient purification process of the most important wheat ATIs. This paves the way for further in-depth investigation of the ATIs to gain more knowledge related to their involvement in NCWS disease and to allow the absolute quantification in wheat samples.},
  language  = {en}
}
@article{SaguTchewonpiLandgraeberRackiewiczetal.2020,
  author    = {Sagu Tchewonpi, Sorel and Landgr{\"a}ber, Eva and Rackiewicz, Michal and Huschek, Gerd and Rawel, Harshadrai Manilal},
  title     = {Relative Abundance of Alpha-Amylase/Trypsin Inhibitors in Selected Sorghum Cultivars},
  series = {Molecules},
  volume    = {25},
  journal   = {Molecules},
  number    = {24},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1420-3049},
  doi       = {10.3390/molecules25245982},
  pages     = {19},
  year      = {2020},
  abstract  = {Sorghum is of growing interest and considered as a safe food for wheat related disorders. Besides the gluten, α-amylase/trypsin-inhibitors (ATIs) have been identified as probable candidates for these disorders. Several studies focused on wheat-ATIs although there is still a lack of data referring to the relative abundance of sorghum-ATIs. The objective of this work was therefore to contribute to the characterization of sorghum ATI profiles by targeted proteomics tools. Fifteen sorghum cultivars from different regions were investigated with raw proteins ranging from 7.9 to 17.0 g/100 g. Ammonium bicarbonate buffer in combination with urea was applied for protein extraction, with concentration from 0.588 ± 0.047 to 4.140 ± 0.066 mg/mL. Corresponding electrophoresis data showed different protein profiles. UniProtKB data base research reveals two sorghum ATIs, P81367 and P81368; both reviewed and a targeted LC-MS/MS method was developed to analyze these. Quantifier peptides ELAAVPSR (P81367) and TYMVR (P81368) were identified and retained as biomarkers for relative quantification. Different reducing and alkylating agents were assessed and combination of tris (2 carboxyethyl) phosphine/iodoacetamide gave the best response. Linearity was demonstrated for the quantifier peptides with standard recovery between 92.2 and 107.6\%. Nine sorghum cultivars presented up to 60 times lower ATI contents as compared to wheat samples. This data suggests that sorghum can effectively be considered as a good alternative to wheat.},
  language  = {en}
}
@article{FigueroaCamposGKTKruizengaSaguTchewonpietal.2022,
  author    = {Figueroa Campos, Gustavo Adolfo and G. K. T. Kruizenga, Johannes and Sagu Tchewonpi, Sorel and Schwarz, Steffen and Homann, Thomas and Taubert, Andreas and Rawel, Harshadrai Manilal},
  title     = {Effect of the post-harvest processing on protein modification in green coffee beans by phenolic compounds},
  series = {Foods : open access journal},
  volume    = {11},
  journal   = {Foods : open access journal},
  edition   = {2},
  publisher = {MDPI},
  address   = {Basel, Schweiz},
  issn      = {2304-8158},
  doi       = {10.3390/foods11020159},
  pages     = {19},
  year      = {2022},
  abstract  = {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},
  language  = {en}
}
@misc{FigueroaCamposGKTKruizengaSaguTchewonpietal.2022,
  author    = {Figueroa Campos, Gustavo A. and G. K. T. Kruizenga, Johannes and Sagu Tchewonpi, Sorel and Schwarz, Steffen and Homann, Thomas and Taubert, Andreas and Rawel, Harshadrai},
  title     = {Effect of the Post-Harvest Processing on Protein Modification in Green Coffee Beans by Phenolic Compounds},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  volume    = {11},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  edition   = {2},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-55764},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-557643},
  pages     = {1 -- 19},
  year      = {2022},
  abstract  = {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},
  language  = {en}
}
@misc{FigueroaCamposPerezBlocketal.2021,
  author    = {Figueroa Campos, Gustavo A. and Perez, Jeffrey Paulo H. and Block, Inga and Tchewonpi Sagu, Sorel and Saravia Celis, Pedro and Taubert, Andreas and Rawel, Harshadrai Manilal},
  title     = {Preparation of activated carbons from spent coffee and coffee parchment and assessment of their adsorbent efficiency},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {8},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-52191},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-521914},
  pages     = {20},
  year      = {2021},
  abstract  = {The valorization of coffee wastes through modification to activated carbon has been considered as a low-cost adsorbent with prospective to compete with commercial carbons. So far, very few studies have referred to the valorization of coffee parchment into activated carbon. Moreover, low-cost and efficient activation methods need to be more investigated. The aim of this work was to prepare activated carbon from spent coffee grounds and parchment, and to assess their adsorption performance. The co-calcination processing with calcium carbonate was used to prepare the activated carbons, and their adsorption capacity for organic acids, phenolic compounds and proteins was evaluated. Both spent coffee grounds and parchment showed yields after the calcination and washing treatments of around 9.0\%. The adsorption of lactic acid was found to be optimal at pH 2. The maximum adsorption capacity of lactic acid with standard commercial granular activated carbon was 73.78 mg/g, while the values of 32.33 and 14.73 mg/g were registered for the parchment and spent coffee grounds activated carbons, respectively. The Langmuir isotherm showed that lactic acid was adsorbed as a monolayer and distributed homogeneously on the surface. Around 50\% of total phenols and protein content from coffee wastewater were adsorbed after treatment with the prepared activated carbons, while 44, 43, and up to 84\% of hydrophobic compounds were removed using parchment, spent coffee grounds and commercial activated carbon, respectively; the adsorption efficiencies of hydrophilic compounds ranged between 13 and 48\%. Finally, these results illustrate the potential valorization of coffee by-products parchment and spent coffee grounds into activated carbon and their use as low-cost adsorbent for the removal of organic compounds from aqueous solutions.},
  language  = {en}
}
@article{SilvaOliveiraCostaTchewonpietal.2021,
  author    = {Silva, Bibiana and Oliveira Costa, Ana Carolina and Tchewonpi, Sorel Sagu and B{\"o}nick, Josephine and Huschek, Gerd and Gonzaga, Luciano Valdemiro and Fett, Roseane and Baldermann, Susanne and Rawel, Harshadrai Manilal},
  title     = {Comparative quantification and differentiation of bracatinga (Mimosa scabrella Bentham) honeydew honey proteins using targeted peptide markers identified by high-resolution mass spectrometry},
  series = {Food research international},
  volume    = {141},
  journal   = {Food research international},
  publisher = {Elsevier},
  address   = {New York, NY [u.a.]},
  issn      = {0963-9969},
  doi       = {10.1016/j.foodres.2020.109991},
  pages     = {10},
  year      = {2021},
  abstract  = {Honey traceability is an important topic, especially for honeydew honeys, due to the increased incidence of adulteration. This study aimed to establish specific markers to quantify proteins in honey. A proteomics strategy to identify marker peptides from bracatinga honeydew honey was therefore developed. The proteomics approach was based on initial untargeted identification of honey proteins and peptides by LC-ESI-Triple-TOF-MS/MS, which identified the major royal jelly proteins (MRJP) presence. Afterwards, the peptides were selected by the in silico digestion. The marker peptides were quantified by the developed targeted LC-QqQ-MS/MS method, which provided good linearity and specificity, besides recoveries between 92 and 100\% to quantify peptides from bracatinga honeydew honey. The uniqueness and high response in mass spectrometry were backed by further complementary protein analysis (SDS-PAGE). The selected marker peptides EALPHVPIFDR (MRJP 1), ILGANVK (MRJP 2), TFVTIER (MRJP 3), QNIDVVAR (MRJP 4), FINNDYNFNEVNFR (MRJP 5) and LLQPYPDWSWTK (MRJP 7), quantified by LC-QqQ-MS/MS, highlighted that the content of QNIDVVAR from MRJP 4 could be used to differentiate bracatinga honeydew honey from floral honeys (p < 0.05) as a potential marker for its authentication. Finally, principal components analysis highlighted the QNIDVVAR content as a good descriptor of the analyzed bracatinga honeydew honey samples.},
  language  = {en}
}
@article{FigueroaCamposPerezBlocketal.2021,
  author    = {Figueroa Campos, Gustavo Adolfo and Perez, Jeffrey Paulo H. and Block, Inga and Sagu Tchewonpi, Sorel and Saravia Celis, Pedro and Taubert, Andreas and Rawel, Harshadrai Manilal},
  title     = {Preparation of activated carbons from spent coffee and coffee parchment and assessment of their adsorbent efficiency},
  series = {Processes : open access journal},
  volume    = {9},
  journal   = {Processes : open access journal},
  number    = {8},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2227-9717},
  doi       = {10.3390/pr9081396},
  pages     = {18},
  year      = {2021},
  abstract  = {The valorization of coffee wastes through modification to activated carbon has been considered as a low-cost adsorbent with prospective to compete with commercial carbons. So far, very few studies have referred to the valorization of coffee parchment into activated carbon. Moreover, low-cost and efficient activation methods need to be more investigated. The aim of this work was to prepare activated carbon from spent coffee grounds and parchment, and to assess their adsorption performance. The co-calcination processing with calcium carbonate was used to prepare the activated carbons, and their adsorption capacity for organic acids, phenolic compounds and proteins was evaluated. Both spent coffee grounds and parchment showed yields after the calcination and washing treatments of around 9.0\%. The adsorption of lactic acid was found to be optimal at pH 2. The maximum adsorption capacity of lactic acid with standard commercial granular activated carbon was 73.78 mg/g, while the values of 32.33 and 14.73 mg/g were registered for the parchment and spent coffee grounds activated carbons, respectively. The Langmuir isotherm showed that lactic acid was adsorbed as a monolayer and distributed homogeneously on the surface. Around 50\% of total phenols and protein content from coffee wastewater were adsorbed after treatment with the prepared activated carbons, while 44, 43, and up to 84\% of hydrophobic compounds were removed using parchment, spent coffee grounds and commercial activated carbon, respectively; the adsorption efficiencies of hydrophilic compounds ranged between 13 and 48\%. Finally, these results illustrate the potential valorization of coffee by-products parchment and spent coffee grounds into activated carbon and their use as low-cost adsorbent for the removal of organic compounds from aqueous solutions.},
  language  = {en}
}
@article{SaguTchewonpiRawelRohn2022,
  author    = {Sagu Tchewonpi, Sorel and Rawel, Harshadrai M. and Rohn, Sascha},
  title     = {Targeted bottom-up mass spectrometry approach for the relative quantification of post-translational modification of bovine κ-casein during milk fermentation},
  series = {Molecules},
  volume    = {27},
  journal   = {Molecules},
  number    = {18},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1420-3049},
  doi       = {10.3390/molecules27185834},
  pages     = {17},
  year      = {2022},
  abstract  = {kappa-casein (kappa-CN) is one of the key components in bovine milk, playing a unique role in the structuration of casein micelles. It contains in its chemical structure up to sixteen amino acid residues (mainly serine and threonine) susceptible to modifications, including glycosylation and phosphorylation, which may further be formed during milk processing. In this study, changes in post-translational modification (PTM) of kappa-CN during bovine milk fermentation were investigated. One-to-five-day fermented milk samples were produced. A traditional bottom-up proteomics approach was used to establish a multiple-reaction monitoring (MRM) method for relative quantification of kappa-CN PTM. Endoproteinase Glu-C was found to efficiently digest the kappa-CN molecule. The developed LC-MS method was validated by performing assessments of linearity, precision, repeatability, reproducibility, limit of detection (LOD), and limit of quantification (LOQ). Among the yielded peptides, four of them containing serine and threonine residues were identified and the unmodified as well as the modified variants of each of them were relatively quantified. These peptides were (1) IPTINTIASGEPTSTTE ([140, 158]), (2) STVATLE ([162, 168]), (3) DSPE ([169, 172]), and (4) INTVQVTSTAV ([180, 190]). Distribution analysis between unmodified and modified peptides revealed that over 50\% of kappa-CN was found in one of its modified forms in milk. The fermentation process further significantly altered the composition between unmodified/modified kappa-CN, with glycoslaytion being predominant compared to phosphorylation (p < 0.01). Further method development towards alpha and beta-CN fractions and their PTM behavior would be an asset to better understand the changes undergone by milk proteins and the micellar structure during fermentation.},
  language  = {en}
}
@article{TchewonpiSaguLandgraeberHenkeletal.2021,
  author    = {Tchewonpi Sagu, Sorel and Landgr{\"a}ber, Eva and Henkel, Ina M. and Huschek, Gerd and Homann, Thomas and Bußler, Sara and Schl{\"u}ter, Oliver and Rawel, Harshadrai Manilal},
  title     = {Effect of cereal α-amylase/trypsin inhibitors on developmental characteristics and abundance of digestive enzymes of mealworm larvae (Tenebrio molitor L.)},
  series = {Insects : open access journal},
  volume    = {12},
  journal   = {Insects : open access journal},
  number    = {5},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2075-4450},
  doi       = {10.3390/insects12050454},
  pages     = {16},
  year      = {2021},
  abstract  = {The objective of this work was to investigate the potential effect of cereal α-amylase/trypsin inhibitors (ATIs) on growth parameters and selective digestive enzymes of Tenebrio molitor L. larvae. The approach consisted of feeding the larvae with wheat, sorghum and rice meals containing different levels and composition of α-amylase/trypsin inhibitors. The developmental and biochemical characteristics of the larvae were assessed over feeding periods of 5 h, 5 days and 10 days, and the relative abundance of α-amylase and selected proteases in larvae were determined using liquid chromatography tandem mass spectrometry. Overall, weight gains ranged from 21\% to 42\% after five days of feeding. The larval death rate significantly increased in all groups after 10 days of feeding (p < 0.05), whereas the pupation rate was about 25\% among larvae fed with rice (Oryza sativa L.) and Siyazan/Esperya wheat meals, and only 8\% and 14\% among those fed with Damougari and S35 sorghum meals. As determined using the Lowry method, the protein contents of the sodium phosphate extracts ranged from 7.80 ± 0.09 to 9.42 ± 0.19 mg/mL and those of the ammonium bicarbonate/urea reached 19.78 ± 0.16 to 37.47 ± 1.38 mg/mL. The total protein contents of the larvae according to the Kjeldahl method ranged from 44.0 and 49.9 g/100 g. The relative abundance of α-amylase, CLIP domain-containing serine protease, modular serine protease zymogen and C1 family cathepsin significantly decreased in the larvae, whereas dipeptidylpeptidase I and chymotrypsin increased within the first hours after feeding (p < 0.05). Trypsin content was found to be constant independently of time or feed material. Finally, based on the results we obtained, it was difficult to substantively draw conclusions on the likely effects of meal ATI composition on larval developmental characteristics, but their effects on the digestive enzyme expression remain relevant.},
  language  = {en}
}
@article{HuschekRawelSchweikertetal.2022,
  author    = {Huschek, Gerd and Rawel, Harshadrai M. and Schweikert, Torsten and Henkel-Oberl{\"a}nder, Janin and Sagu Tchewonpi, Sorel},
  title     = {Characterization and optimization of microwave-assisted extraction of B-phycoerythrin from Porphyridium purpureum using response surface methodology and Doehlert design},
  series = {Bioresource Technology Reports},
  volume    = {19},
  journal   = {Bioresource Technology Reports},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {2589-014X},
  doi       = {10.1016/j.biteb.2022.101212},
  pages     = {9},
  year      = {2022},
  abstract  = {Microalgae are one of the most promising food source of the future. Nowadays, extracts of high-value active substances of biomass are business aims for the development of food additives in personalized nutrition, in cosmetics and pharmaceuticals. A new-patented vertical farming cultivation technology was used for production of Porphyridium purpureum. In this work, microwave assisted extraction was used to extract B-phycoerythrin from Porphyridium purpureum biomass. Response surface methodology was implemented for optimization. Numerical optimization established the best point of the experimental domain (biomass/solvent of 16.8 mg/mL, time of 172 s, and temperature of 30 degrees C) with a desirability value of 0.82. Corresponding experimental responses values of 7.2 mg, 8.5 \% and 13,961 PA/mu g biomass were obtained for extracted proteins, extraction yield and extracted B-phycoerythrin, respectively. Final freeze-dried product indicated protein content of 55 \% using Kjeldahl while targeted mass spectrometry analysis revealed that B-phycoerythrin represented 93 \% of the total protein.},
  language  = {en}
}