@article{ReinkensmeierBasslerSchlueteretal.2015, author = {Reinkensmeier, Annika and Bassler, Sara and Schlueter, Oliver and Rohn, Sascha and Rawel, Harshadrai Manilal}, title = {Characterization of individual proteins in pea protein isolates and air classified samples}, series = {Food research international}, volume = {76}, journal = {Food research international}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0963-9969}, doi = {10.1016/j.foodres.2015.05.009}, pages = {160 -- 167}, year = {2015}, abstract = {Generally, pea proteins are extracted at comparatively acidic or basic pH values to provide a basis for protein isolate production. Such processing steps result in partial denaturation of the proteins rendering them in most cases insoluble at food processing pH conditions and limiting their application in food products. Here, the comparison of the solubility properties of pea proteins in protein enriched fractions deriving from air classification is reported. Protein content, solubility, and physicochemical parameters of different fractions of the pea (Pisum sativum) variety 'Salamanca' were investigated as a function of pH using SDS-PAGE and surface hydrophobicity. Whole pea flour (20\% protein), air classified, protein-enriched pea flour (48\% protein), pea flour made from hulls (2.8\% protein), and pea protein isolate (81\% protein) served as test materials. Fractionation and pH value affected the composition and surface hydrophobicity of the proteins as well as the content of trypsin inhibitors. All samples showed a high buffering capacity in the range of pH 4 to 10. The direct comparison documents the comparatively better protein quality of the air classified, protein enriched pea fraction. The solubility of the pea protein isolate can be improved by using selected additives, giving new possibilities for plant protein application. Relevant technofunctional properties were determined and compared with two commercially available pea-based products (whole pea flour and an isolate). Water binding capacity was highest for the commercially available pea flour followed by the pea hull flour. Fat binding capacity remained more or less unchanged. (C) 2015 Elsevier Ltd. All rights reserved.}, language = {en} } @article{KhozroughiKrohSchlueteretal.2018, author = {Khozroughi, Amin Ghadiri and Kroh, Lothar W. and Schlueter, Oliver and Rawel, Harshadrai Manilal}, title = {Assessment of the bacterial impact on the post-mortem formation of zinc protoporphyrin IX in pork meat}, series = {Food chemistry}, volume = {256}, journal = {Food chemistry}, publisher = {Elsevier}, address = {Oxford}, issn = {0308-8146}, doi = {10.1016/j.foodchem.2018.01.045}, pages = {25 -- 30}, year = {2018}, abstract = {The post-mortem accumulation of the heme biosynthesis metabolite zinc protoporphyrin IX (ZnPP) in porcine muscle is associated with both a meat-inherent and a bacterial enzymatic reaction during meat storage. To estimate the bacterial impact on ZnPP formation, meat and meat-like media were investigated by HPLC-FLD (and MALDI-TOF-MS) after inoculation with a representative microorganism (P. fluorescens). Results indicate the principal ability of meat-inherent bacteria to form ZnPP in meat extracts and meat-like media, but not on the meat muscle. Thus it was concluded that the ZnPP formation in meat is due to a meat-inherent enzymatic reaction induced by porcine ferrochelatase (FECH), while the bacterial (FECH) induced reaction seems to be not significant.}, language = {en} } @article{KhozroughiJanderSchirrmannetal.2017, author = {Khozroughi, Amin Ghadiri and Jander, Elisabeth and Schirrmann, Michael and Rawel, Harshadrai Manilal and Kroh, Lothar W. and Schlueter, Oliver}, title = {The role of myoglobin degradation in the formation of zinc protoporphyrin IX in the longissimus lumborum of pork}, series = {LWT - food science and technology : an official journal of the Swiss Society of Food Science and Technology (SGLWT/SOSSTA) and the International Union of Food Science and Technology (IUFoST)}, volume = {85}, journal = {LWT - food science and technology : an official journal of the Swiss Society of Food Science and Technology (SGLWT/SOSSTA) and the International Union of Food Science and Technology (IUFoST)}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0023-6438}, doi = {10.1016/j.lwt.2017.06.047}, pages = {22 -- 27}, year = {2017}, abstract = {Investigations on the post mortal formation of fluorescent zinc protoporphyrin (ZnPP) IX in pork meat are currently in focus of meat science research. The role of myoglobin degradation in this context appears to be one of the most diversely discussed issues. To address this question meat-extracts of longissimus lumborum (LL) muscle (0.8 mg/mL) were incubated at 30 degrees C for up to 72 h and investigated by HPSEC-UV-fluorescence, SDS-PAGE and MALDI-TOF-MS. Between 0 and 72 h of incubation the fluorescence intensity (lambda(ex)./(em). = 420/590 nm) of the meat-extracts rose significantly (p < 0.001) from 10.9 +/- 0.8 to 34.8 +/- 0.3 (rel. units) while the staining intensity of the SDS-PAGE of myoglobin non-significantly (p > 0.4) changed from 6.2 +/- 0.5 x 105 to 5.0 +/- 0.3 x 105 (rel. units). The results indicate that ZnPP is formed by a Fe(II)-Zn(II)-substitution in myoglobin heme where an accompanying myoglobin degradation is not necessarily obligatory. (C) 2017 Elsevier Ltd. All rights reserved.}, language = {en} }