TY  - JOUR
A1  - Islam, Khan M. S.
A1  - Khalil, Mahmoud Abd Elhamid
A1  - Maenner, Klaus
A1  - Raila, Jens
A1  - Rawel, Harshadrai Manilal
A1  - Zentek, Jürgen
A1  - Schweigert, Florian J.
T1  - Lutein Specific Relationships among Some Spectrophotometric and Colorimetric Parameters of Chicken Egg Yolk
JF  - The journal of poultry science
N2  - Lutein is an essential dietary carotenoid with health benefits and is inter alia responsible for the colouration of egg yolk. The relationship between lutein accumulation and egg yolk colouration was therefore studied in more detail. After feeding a low-luteine diet for 21 days, 14 birds (Lohmann brown hens aged 20 weeks) were fed a diet containing marigold (80 mg lutein/kg feed) and 14 other birds were fed a diet containing oleoresin (45 mg lutein/kg feed) for 21 days; for both groups of birds, this feeding period was followed by withdrawal for 21 days. The Roche Yolk Colour Fan (RYCF) score (0 to 15, where higher values denote greater colour intensity; R-2=0.87; P<0.01) and redness (R-2=0.89; P<0.01) increased with increasing lutein content of egg yolk. Total carotenoid content had a poor relationship with lightness (R-2=0.13; P>0.05) and yellowness (R-2=0.12; P>0.05) of the yolk. It may be concluded that increased lutein is potentially responsible for an increased RYCF score and redness (a*), but decreased yellowness (b*) and lightness (L*), of egg yolk.
KW  - carotenoid
KW  - HPLC
KW  - iCheck
KW  - lutein
KW  - spectrophotometry
KW  - yolk
Y1  - 2017
U6  - https://doi.org/10.2141/jpsa.0160065
SN  - 1346-7395
VL  - 54
SP  - 271
EP  - 277
PB  - Japan Poultry Science Association
CY  - Tsukuba
ER  - 
TY  - JOUR
A1  - Zühlke, Martin
A1  - Sass, Stephan
A1  - Riebe, Daniel
A1  - Beitz, Toralf
A1  - Löhmannsröben, Hans-Gerd
T1  - Real-Time Reaction Monitoring of an Organic Multistep Reaction by Electrospray Ionization-Ion Mobility Spectrometry
JF  - ChemPlusChem
N2  - The capability of electrospray ionization (ESI)-ion mobility (IM) spectrometry for reaction monitoring is assessed both as a stand-alone real-time technique and in combination with HPLC. A three-step chemical reaction, consisting of a Williamson ether synthesis followed by a hydrogenation and an N-alkylation step, is chosen for demonstration. Intermediates and products are determined with a drift time to mass-per-charge correlation. Addition of an HPLC column to the setup increases the separation power and allows the determination of further species. Monitoring of the intensities of the various species over the reaction time allows the detection of the end of reaction, determination of the rate-limiting step, observation of the system response in discontinuous processes, and optimization of the mass ratios of the starting materials. However, charge competition in ESI influences the quantitative detection of substances in the reaction mixture. Therefore, two different methods are investigated, which allow the quantification and investigation of reaction kinetics. The first method is based on the pre-separation of the compounds on an HPLC column and their subsequent individual detection in the ESI-IM spectrometer. The second method involves an extended calibration procedure, which considers charge competition effects and facilitates nearly real-time quantification.
KW  - electrospray ionization
KW  - HPLC
KW  - ion mobility spectrometry
KW  - reaction mechanisms
KW  - reaction monitoring
Y1  - 2017
U6  - https://doi.org/10.1002/cplu.201700296
SN  - 2192-6506
VL  - 82
SP  - 1266
EP  - 1273
PB  - Wiley-VCH
CY  - Weinheim
ER  -