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Reconstitution properties of micellar casein powders with different calcium contents and their production.

Z. Atamer

Events

06-22-2020

Abstract:

97
Reconstitution properties of micellar casein powders with different calcium contents and their production.
J. Sch�fer1, R. Kohlus2, J. Hinrichs1, Z. Atamer*1. 1Department of Soft Matter Science and Dairy Technology, Institute of Food Science and Biotechnology, University of Hohenheim Stuttgart, Germany, 2Department of Process Engineering and Food Powders, Institute of Food Science and Biotechnology, University of Hohenheim Stuttgart, Germany.

Micellar casein (mCN) powders have poor reconstitution properties, in particular at low temperatures. The solubility of milk protein powders can be improved by reducing calcium content. Therefore, the study aimed (1) to manufacture calcium reduced mCN powder on a technical scale, and (2) to investigate the reconstitution properties of mCN powders with different calcium contents. For the production of a high-calcium depleted mCN concentrates, the skim milk was first acidified to pH 6.2 (1), and microfiltered (0.1 μm) (2). The retentate was acidified to pH 5.6 (3), and microfiltered in diafiltration modus using demineralized water in 6 steps (4). Finally, the obtained retentate was spray dried (5). For comparison purposes, a slightly-calcium reduced mCN powder was also manufactured. As a reference, non-calcium-depleted mCN was manufactured via concentrating the skim milk using microfiltration and spray drying the resulting retentate. The influence of the calcium content on the solubility and the effect of drying on particle size, apparent viscosity, sol-gel transition, were investigated. A technical-scale production of mCN powder containing different levels of calcium was shown to be possible. The solubility experiments showed that the non-calcium reduced spray-dried powder (calcium content: 19820 � 330 mg kg−1) had 0.5 � 0.1 mL sediment, whereas the calcium-reduced micellar casein powders (slightly depleted: calcium content: 27170 � 10 mg kg−1 and highly depleted: calcium content: 15250 � 210 mg kg−1) contained 3.8 � 1.1 mL and 3.4 � 0.1 mL, respectively, indicating a significantly decreased solubility due to calcium depletion (P < 0.05). The particle size of the reconstituted high-calcium depleted mCN concentrate was significantly bigger (206.3 � 8.8 nm) (P < 0.05) compared with non- and slightly-calcium depleted mCN concentrates (172.0 � 2.1 and 174.8 � 8.1 nm), which were not significantly different in their sizes.

Keywords: solubility, calcium depletion, casein concentrate.

Biography: Zeynep Atamer is a postdoctoral researcher�in the Department of Soft Matter Science and Dairy Technology at the University of Hohenheim in Stuttgart, Germany. Her fields of expertise are dairy microbiology, fractionation of casein proteins, membrane separation process as well as fresh cheese technology. She obtained her BSc degree in Food Engineering from the Middle East Technical University, Ankara, Turkey, together with a minor degree in Environmental Chemistry. Afterwards she attended the international MSc Program in Environmental Protection and Food Production at the University of Hohenheim in Stuttgart, Germany. She did her master thesis in Tetra Pak Research and Development Stuttgart, where she investigated different heating systems used in dairy applications. She subsequently started her PhD in the Department of Soft Matter Science and Dairy Technology at the University of Hohenheim with a topic on dairy bacteriophages. Following her PhD, she then worked as a visiting researcher at the Department of Food Engineering of Akdeniz University, Antalya, Turkey within the scope of an international cooperation project with the University of Hohenheim. Over the course of her academic career, she has published, in total, 5 book chapters, 37 peer-reviewed journals, 14 non-peer-reviewed journals and more than 50 contributions to conference proceedings (with oral presentations and posters).