TY  - JOUR
A1  - Khozroughi, Amin Ghadiri
A1  - Braga, Tess Waldbach
A1  - Wagner, Janine
A1  - Rawel, Harshadrai Manilal
T1  - Investigation of the post mortem zinc protoporphyrin IX fluorescence with respect to its protein-bound and unbound occurrence in aqueous meat extracts
JF  - Food chemistry
N2  - Zinc protoporphyrin IX (ZnPP) is known to accumulate in most meat products during storage. However, the pathway of its formation is not yet completely clarified. To gain more insights into the specificity of ZnPP occurrence, a SEC-HPLC-UV-fluorescence setup was established to screen the proteins in aqueous meat extracts for their ZnPP fluorescence during incubation. In accordance with previous studies it was identified by SDS-PAGE and MALDI-TOF-MS that ZnPP formation takes place in myoglobin. In this study, valuable new insights into the ZnPP forming pathway were gained, as our results indicated that a significant part of ZnPP - after being formed within the protein - is transitioned into free ZnPP during incubation. Additionally, the obtained results implied that ZnPP may also occur in proteins of higher molecular weight (> 100 kDa).
KW  - Meat
KW  - Fluorescence screening
KW  - Post mortem chemistry
KW  - SDS-PAGE
KW  - SEC-HPLC
KW  - MALDI-TOF-MS
Y1  - 2019
U6  - https://doi.org/10.1016/j.foodchem.2019.01.080
SN  - 0308-8146
SN  - 1873-7072
VL  - 283
SP  - 462
EP  - 467
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Khozroughi, Amin Ghadiri
A1  - Jander, Elisabeth
A1  - Schirrmann, Michael
A1  - Rawel, Harshadrai Manilal
A1  - Kroh, Lothar W.
A1  - Schlueter, Oliver
T1  - The role of myoglobin degradation in the formation of zinc protoporphyrin IX in the longissimus lumborum of pork
JF  - 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)
N2  - 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.
KW  - Meat
KW  - Fluorescence
KW  - Proteolysis
KW  - Post mortem chemistry
Y1  - 2017
U6  - https://doi.org/10.1016/j.lwt.2017.06.047
SN  - 0023-6438
SN  - 1096-1127
VL  - 85
SP  - 22
EP  - 27
PB  - Elsevier
CY  - Amsterdam
ER  -