TY  - JOUR
A1  - Sagu Tchewonpi, Sorel
A1  - Huschek, Gerd
A1  - Waldbach Braga, Tess
A1  - Rackiewicz, Michal
A1  - Homann, Thomas
A1  - Rawel, Harshadrai Manilal
T1  - Design of Experiment (DoE) for Optimization of HPLC Conditions for the Simultaneous Fractionation of Seven α-Amylase/Trypsin Inhibitors from Wheat (Triticum aestivum L.)
JF  - Processes : open access journal
N2  - 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.
KW  - wheat
KW  - α-amylase/trypsin inhibitors
KW  - fractionation
KW  - purification
KW  - reversed-phase chromatography
KW  - ion-exchange chromatography
KW  - design of experiment
KW  - LC–MS/MS
KW  - MALDI-TOF-MS
Y1  - 2022
U6  - https://doi.org/10.3390/pr10020259
SN  - 2227-9717
VL  - 10
SP  - 1
EP  - 18
PB  - MDPI
CY  - Basel, Schweiz
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  -