The aim of the study was to investigate the properties of sodium caseinate dispersions and oil-in-water emulsions obtained from cows' milk of either A1/A1, A1/A2, or A2/A2 β-casein phenotype. Protein structural characterisation was examined using Fourier Transform Infrared and Nuclear Magnetic Resonance spectroscopies, with physicochemical and interfacial properties assessed by analysing adsorbed protein content, hydrophobicity, solubility, and emulsion stability of the samples. Results showed variations in the secondary structure of all samples dependent of the presence of A1 or A2 β-caseins. The main differences included greater amounts of α-helix and β-sheet in A1/A1 and A1/A2 sodium caseinate dispersions that influenced their lower solubility, while random coils/polyproline II helixes were found only in A2/A2 sodium caseinate dispersion. In contrast, upon adsorption on the interface of A2/A2 sodium caseinate emulsion, the protein adopted ordered conformational motifs. This conformational shift supposedly arose from structural differences between the two β-casein proteoforms, which most likely enhanced the emulsion properties of A2/A2 sodium caseinate compared to either A1/A1 or A1/A2 sodium caseinates. The A2 β-casein in both, A1/A2 and A2/A2 sodium caseinates, appears to be able to more rapidly reach the oil droplet surface and was more efficient as emulsifying agent. The current results demonstrated that the conformational rearrangement of proteins upon adsorption to emulsion interfaces was dependent not only on hydrophobicity and on solubility, but also on the conformational flexibility of A1/A1, A1/A2, and A2/A2 β-casein phenotypes. These findings can assist in predicting the behaviour of sodium caseinates during relevant industrial processing.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.jcis.2022.07.021 | DOI Listing |
Microorganisms
January 2025
Institute of Food Science and Biotechnology, Department of Bioprocess Engineering, University of Hohenheim, Fruwirthstraße 12, 70599 Stuttgart, Germany.
Background: Cow's milk represents an important protein source. Here, especially casein proteins are important components, which might be a promising source of alternative protein production by microbial expression systems. Nevertheless, caseins are difficult-to-produce proteins, making heterologous production challenging.
View Article and Find Full Text PDFFoods
January 2025
Department of Food Science and Technology, School of Agriculture, Shiraz University, Shiraz, Iran.
Emulsifiers with antioxidant properties, such as protein/polyphenol complexes, adsorb at the oil-water interface and improve the physical and oxidative stability of emulsions. Here, 2% (/) sodium caseinate and varying concentrations of phloretin (0-10 mM) were used to stabilize oil-in-water emulsions. Control emulsions with protein alone showed poor stability with increased droplet sizes from 0.
View Article and Find Full Text PDFFood Res Int
February 2025
College of Food Science, Southwest University, Chongqing 400715, PR China. Electronic address:
This study applied high hydrostatic pressure (HHP) treatment to buffalo milk casein to assess the influence of different pressure levels on its structural characteristics, physicochemical properties, and functional properties. The results showed that although HHP had no marked impact on the zeta potential and secondary structure, it altered the protein's spatial structure (primarily its tertiary structure), and improved dispersion properties (such as particle size, solubility, and turbidity), as well as foaming properties. Additionally, HHP improved the antioxidant activity and antibacterial activity against Escherichia coli.
View Article and Find Full Text PDFFood Res Int
February 2025
Department of Agriculture, University of Naples "Federico II", 80055 Portici, Italy.
β-Casomorphins (BCMs), food-associated peptides resulting from the proteolytic cleavage of β-casein (β-CN), have been widely investigated for their opioid-like activity. This research aimed to identify the presence of BCM7, BCM6, and BCM5 in different bovine milk-deriving blue cheese types and to describe the intricate mechanisms behind their formation, focusing on their origin from cheese with β-CN A1 and A2 variants. Using nanoLC-ESI-Q-Orbitrap-MS/MS and advanced computational tools, we explored the peptidomes of Bleu d'Auvergne, Gorgonzola, Stilton, and Bergader blue cheeses from milk containing both β-CN A1 and A2 variants.
View Article and Find Full Text PDFFood Res Int
February 2025
Université de Lille, UMRT 1158 BioEcoAgro, F-59000 Lille, France. Electronic address:
Besides their nutritional role, proteins are recognized for their ability to regulate both short- and long-term energy homeostasis. However, studies investigating the effects of proteins based on their quality and origin remain limited and often lack comparability. Nonetheless, existing research consistently underscores the influence of proteins on food intake regulation.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!