DOCTORAL CANDIDATE 5

DC5 will build a mid-IR-laser based analyser prototype (together with DC7) for fast and direct quantification of the three main proteins present in human milk (HM) samples, i.e., casein, α-lactalbumin, and lactoferrin. An EC-QCL source (IAF) covering the spectral range from 1700-1500 cm-1 will be used as well as ICL arrays (DC1). The analyser will allow operation in the flow through mode. Initially, the currently available PTS set-up (MTU) will be improved, and its performance evaluated against difference absorbance spectroscopy employing a balanced detector (TU-WIEN). Both analysers will be equipped with a flow cell for rapid sample exchange and intermittent cleaning to avoid sample carry over effects. The DC will prepare standard protein mixtures at IISLAFE and using reference analysis methods (ELISA test kits or in-house developed chromatographic methods) and a multivariate calibration (PLS) model will be established and validated. The developed prototype will be benchmarked in a clinical environment through the analysis of HM samples across different postnatal ages covering from birth until >12 months of infant age as well as across different gestational ages covering from <28 to >40 weeks of gestation for the establishment of reference ranges. DC5 shall also receive training in sample preparation as required for HPLC-MS, or GC-MS analysis enabling the DC to carry out complementary analysis which provides access to e.g. the fatty acid profile in human milk. The correlation between individual proteins concentrations and possibly also other parameters on infant growth, weight gain, and z-score will be studied. Furthermore, HM samples collected before and after Holder pasteurization (i.e., 30 min at 62.5 °C) will be studied to investigate the effect of heat treatment on individual proteins as thermal denaturation might occur.