Bernhard Wager has her expertise in the field of analytical chemistry in the field of pharmaceuticals, food additives and food analysis. He has developed several analytical methods in the analytical field of LC-MS/MS to support food analysis and clinical studies studies in biological matrices studying the impact of administer food and food additives. His experience in research, teaching has focused at the FH JOANNEUM – University of Applied Sciences, Graz, Austria.
Today’s consumers demand foods and beverages that are safe, quality, and nutritious. Food analysis is of great importance when it comes to ensuring the quality of modern food demands. Multiple-heart cutting (MHC) 2D-LC_MS/MS is an alternative technique overcoming disadvantages of 1D-LC analysis, by not resolving isomers and similar substances of phytochemicals, vitamins, amino acids. Even though the potential of MHC-2D-LC enhances significantly separation performances and analyte identification strategies, several details are to consider, achieving reliable results. MS analysis after non-volatile buffers or reagents in the first LC-dimension is not a straightforward procedure, mostly due to the incompatibility of common buffers used in LC-UV analysis, with the electrospray ionization process. Analytical column setup in the first and second LC-dimension, buffer removal strategies and method development are of crucial importance when it comes to LC-MS/MS detection in the third analytical dimension. Mass spectrometry detection is a powerful tool to gain structural information, resolving co-eluting analytes, but isomers cannot resolve even by using HRMS instruments. Therefore, a 2nd chromatographic dimension gives the possibility to separate and the detect those phytochemical or amino acid isomers in one analytical run. This approach allows a fast and reliable gain of information about the ingredients in foods and beverages.
Dr Cynthia Sun obtained her Ph.D in 1999 jointly from the Chemistry Department and School of Biological Sciences at the University of Auckland, New Zealand. Her PhD research was about the bioactivity of hydrolysed milkfat catalysed by lipases. Cynthia’s interests in the discovery of functionalities in natural products after modification by enzymes continued after joining Callaghan Innovation. As a senior research scientist, her recent research topics cover enzyme/protein purification, biotransformation of glycoconjugates, post-harvest modification of natural products, and bioactive compound identification and extraction, all sharing a common goal - to develop novel and value-add ingredients from natural resources.
Groper roe and salmon roe were hydrolysed by three commercial proteases: Alcalase, Protex 6L and Neutrase, respectively, under their optimum pHs and working temperatures for 90 min. The hydrolysates were produced with varied degrees of hydrolysis (10-40%), then investigated for their physical and functional properties, including emulsion stability, solubility, antioxidant activity and anti-hypertensive effect. The hydrolysates from groper roe and salmon roe were firstly compared based on their water solubility and emulsifying capacity: the groper roe hydrolysates were much more hydrophilic than that from salmon roe; the water solubility of the latter is 75% lower than the former. Protex and Neutrase hydrolysates from groper roe demonstrated full emulsion stability (100%) while the Alcalase hydrolysate from groper roe and all three hydrolysates from salmon roehad 55-65%. The physical properties of the hydrolysates were also characterised via scanning electron microscope (SEM), circular dichroism (CD), and dynamic light scattering (Zetasizer) for structure imaging, protein secondary structure, particle sizes and electrostatic forces between molecules, and the changes of these properties under increasing temperature. The Neutrase hydrolysate from groper roe displayed a distinctive fibrillar structure (long, linear and networked, rod-like shapes at 200-700 nm width). This fibrillar structure could explain the hydrolysate’s gelling ability when heated up to 85°C. In contrast, all the other hydrolysates were small, round, individual particles in 35-250 µm diameter, without network connections, and none of these hydrolysates demonstrated the gelling property with increasing temperature up to 90°C. All hydrolysates from groper roe demonstrated antioxidant activities measured by DPPH assay at 5 mg/ml and above. The Alcalase hydrolysates displayed increasing DPPH scavenging activity with increasing degree of hydrolysis, while the other two hydrolysates did not show this trend. The Salmon roe hydrolysates didn’t show convincing scavenging activity in any of the concentrations tested (0.1 -10 mg/ml). Anti-hypertensive properties were measured via the angiotensin I converting enzyme (ACE) inhibition assay. All hydrolysates from both groper and salmon roe demonstrated ACE inhibition at the concentration of 1mg/ml. Thisinhibition appeared in the hydrolysate samples undergone 15 min hydrolysis reaction (5-15% DH) and had only slight increase in samples undergone a 90min hydrolysis (10-40% DH). At 1mg/ml, Neutrase hydrolysate from groper roe has 100% inhibition, followed by Alcalase hydrolysate (89%) and Protex hydrolysate (55%). In salmon roe, both Protex and Neutrase hydrolysates demonstrated near 50% inhibition at 1mg/ml, while the Alcalase hydrolysate only had 18%. In summary, the groper roe hydrolysates demonstrated better bioactivities and interesting physical properties in comparison to the salmon roe counterparts. As a low-value and abundant raw material from the fish industry, groper roe has the potential to be utilised (after enzymatic hydrolysis) as a food-grade functional ingredient in formulation applications.