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Insights on the interaction between kefiran and whey proteins through computational analyses
* 1 , 2 , 1 , 3 , * 1
1  Universidad Autónoma Metropolitana
2  Universidad Nacional Autónoma de México
3  University of Windsor
Academic Editor: Julio A. Seijas


Kefiran is an exopolysaccharide (EPS) produced by kefir granules, a microbial consortium formed by yeasts, acetic, and lactic bacteria, which is used in the industry as an emulsifier, stabilizer, thickening, and gelling agent. It also presents antioxidant, antimicrobial, and even hypotensive properties. Additionally, its biofilms have been developed to protect food; these are formed by the interaction of kefiran with whey proteins. The chemical structure of one subunit of kefiran has been reported to be formed by 6 molecules of D-glucose and D-galactose in equimolar quantities. Molecular weight of this polymer could be up to 107 Da, that is 10,000 subunits. However, it is not known how the overall structure of EPS folds or how whey proteins participate in its folding. Therefore, the aim of the present work was to elucidate the way in which kefiran folds and its interaction with the two main whey proteins: α-lactalbumin and β-lactoglobulin, through computational analyses. Results demonstrated that kefiran folds in a spiral shape, forming a linear cylinder. Likewise, it was observed that whey proteins bind on the surface of the cylinder mainly through van der Waals-type interactions. Therefore, the presence of proteins on the surface will contribute to the intermolecular interaction between kefiran cylinders, that help form a larger and complex scaffold.

Keywords: exopolysaccaride; kefir granules; kefiran; proteins