Affecting Casein Micelles by Pulsed Electrical Field (PEF) for Inclusion of Lipophilic Organic Compounds  
[PERSON]  
1 DIL e.V.--German Institute of Food Technologies, 49610 D-Quakenbruck, Germany;  
d.middendorf@diel-evdc (D.M. ); v.heinz@diel-evdc (V.H.) 1 Elea GmbH, 49610 D-Quakenbruck, Germany; [EMAIL_ADDRESS] (C.S. );  
[EMAIL_ADDRESS] (S.T.) 2  
[PERSON]  
1 DIL e.V.--German Institute of Food Technologies, 49610 D-Quakenbruck, Germany;  
d.middendorf@diel-evdc (D.M. ); v.heinz@diel-evdc (V.H.) 1 Elea GmbH, 49610 D-Quakenbruck, Germany; [EMAIL_ADDRESS] (C.S. );  
[EMAIL_ADDRESS] (S.T.) 2  
[PERSON]  
2 Elea GmbH, 49610 D-Quakenbruck, Germany; [EMAIL_ADDRESS] (C.S. );  
[EMAIL_ADDRESS] (S.T.) 2  
[PERSON]  
2 Elea GmbH, 49610 D-Quakenbruck, Germany; [EMAIL_ADDRESS] (C.S. );  
[EMAIL_ADDRESS] (S.T.) 2  
[PERSON]  
1 DIL e.V.--German Institute of Food Technologies, 49610 D-Quakenbruck, Germany;  
d.middendorf@diel-evdc (D.M. ); v.heinz@diel-evdc (V.H.) 2  
as suitable carriers of FSBS [2; 3]. In this study, the possibility of using casein micelles (CM) as suitable carriers was investigated. Native CM can be obtained by the membrane separation process of skimmed milk [4; 5] and are available as an industrially manufactured product. Additionally, production of artificial CM has been known and established for a long time [6; 7]. [PERSON] et al., 2007, were able to show that artificial CM effectively stabilized the lipophilic vitamin D2 in the aqueous phase. Another observed effect was the protection of vitamin D2 from light-induced degradation. In addition, digestion of artificially produced CM in the human intestinal tract was comparable to that of natural micelles. Bioavailability of CM loaded with vitamin D has been described in the literature, and it can be assumed that native CM will behave in the same way [7; 8]. In addition to using artificial CM, there were first approaches to use native CM. [PERSON] et al., 2011, described a method for loading native CM with hydrophobic vitamin D2 by means of high-pressure treatment [9], which has been used for disintegration of micelles [10; 11]. In this \"dissolved\" state, hydrophobic substances such as vitamins were enabled to attach themselves at single casein molecules. If pressure decreased again, micelles were reformed via non-covalent bonds between caseins. These newly organized micelles contained the FSBS, hydrophobic vitamin D2. In another study, binding of vitamin A and retinoic acid to \(\alpha\)- and \(\beta\)-casein is reported [12]. In these investigations, the respective proteins were treated with retinol or retinoic acid in a buffer solution. The authors were able to determine the number of bound retinol molecules at \(\alpha\)- and \(\beta\)-casein and found that \(\alpha\)-casein formed more stable complexes with retinol or retinoic acid than \(\beta\)-casein. Furthermore, binding sites on the respective protein molecules could be calculated [12]. Studies to incorporate \(\beta\)-carotene into CM have already been performed as well. [PERSON] et al., 2017, used native CM obtained from microfiltration of skimmed milk to identify optimal loading conditions temperatures (2, 20, 40 \({}^{\circ}\)C), pH values (6.8 and 5.5) and holding times (5, 15, 30, 60 min). They found that CM were optimally primed at 2 \({}^{\circ}\)C and a pH of 5.5 for 5 min so that loading with \(\beta\)-carotene was performed under those conditions [5]. [PERSON] and [PERSON], 2013, worked with spray-dried casein powders [13]. They investigated the influence of pH and storage time on casein aggregate structural changes, in addition to encapsulation efficiency after spray drying. Total \(\beta\)-carotene loading quantities were higher when a solution with lower pH was used for powder preparation. Furthermore, [PERSON] et al., 2014, encapsulated \(\beta\)-carotene by self-aggregated caseinates [14]. The pH of the sodium caseinate solution, which determined the degree of aggregation, tremendously affected the encapsulation yield and storage stability of \(\beta\)-carotene.