Casein films

Figure 8.3 Fluorescence microscope images of a BSA + p-casein film at the air-water interface having a surface composition of 0.18 mg mf2 of BSA and 1.05 mg m-2 of p-casein. (a) Image taken with mutual filter, (b) Image of same system taken with red filter. Scale bar = 100 pm. Reproduced from Sengupta and Damodaran (2000) with permission.

Casein films formed from aqueous solution without fiulber treatment... 

Whey protein films similar properties to casein films, but water insoluble eating required... 

Sodium caseinates films tested as wrapping on bread preservation of bread texture for 6 hours compared to control (Schou et al. 2005)... 

Schou, M., Longares, A., Montesinos-Herrero, C., Monahan, F.J., O Riordan, D., and O Sullivan, M. (2005). Properties of edible sodium caseinate films and their application as food wrapping. Z,lJT-Foo /5ci. Technol. 38, 605-610. 

Mackie, A.R., Gunning, A.R, Ridout, M.J., Wilde, R.J., and Morris, V.J. Orogenic displacement in mixed 3-lactoglobulin/ (i-casein films at the air/water interface, Langmuir, 17, 6593, 2001a. 

Effect of Nutraceuticals on Physico-Chemical Properties of Sodium Caseinate Films Plasticized with Glycerol... 

Water vapor permeability (WVP) of sodium caseinate films with nutraceutical substances. Film thickness was controlled in a range of 70 to 90 /rm for all films tested. 

Effect puncture strength in sodium caseinate films. The puncture strength was calculated considering the thickness. 

Tg values of sodium caseinate films incorporated with mineral and vitamin C. 

McHugh et al.22 worked with sodium caseinate films and observed that WVP increase from 0.25 to 1.50 g mm/kPa h m2 with film thickness varying from 0.01 to 0.10mm. However, Park et al.18 working with methylcellulose and hydroxy-propyl cellulose films observed that WVP was relatively constant for thickness in the range 0.023 to 0.140 mm. 

Figure 5 Gelatin addition to 24 h old casein films at the n-hexadecane—water interface (pH 1, 0.005 M, 25 °C). The apparent viscosity nj is plotted against time t following the addition , 10 wt % gelatin to 10 wt % casein film o, 10" wt % gelatin to 2.5X 10 wt% casein film. Solid curve represents 10 wt % pure casein film, and dashed curve represents 5X10 wt % casein +...

Benjamins et al (24) studied the effects of aging on the elasticity of (i-casein and K-casein films. The dilatational modulus of K-casein was larger than that of -casein and increased by a factor of three with film age, whereas the dilatational modulus of -casein films changed little with time ( ). K-casein unfolds less at the air/water interface since it has less random structure than Q-casein. This can also be interpreted in terms of K-casein having less direct contact with the film surface at any given protein concentration (25). Significant protein-protein interactions i.e. steric/electrostatic repulsion, are believed to occur between segments of polypeptide chains which extend both above and below the plane of the air/water interface in surface protein films (16,26)... 

Because protein-ba sed foams depend upon the intrinsic molecular properties (extent and nature of protein-protein interactions) of the protein, foaming properties (formation and stabilization) can vary immensely between different proteins. The intrinsic properties of the protein together with extrinsic factors (temperature, pH, salts, and viscosity of the continuous phase) determine the physical stability of the film. Films with enhanced mechanical strength (greater protein-protein interactions), and better rheological and viscoelastic properties (flexible residual tertiary structure) are more stable (12,15), and this is reflected in more stable foams/emulsions (14,33). Such films have better viscoelastic properties (dilatational modulus) ( ) and can adapt to physical perturbations without rupture. This is illustrated by -lactoglobulin which forms strong viscous films while casein films show limited viscosity due to diminished protein-protein (electrostatic) interactions and lack of bulky structure (steric effects) which apparently improves interactions at the interface (7,13 19). 

Nanoliposomes compared to liposomes provide more surface area and have the potential to increase solubility, enhance bioavailability, and improve controlled release. The principal constituents of nanoliposomes are phospholipids for example, soya, rapeseed, and marine lecithin used by Zhang et al. (2012b). Jimenez et al. (2014) incorporated antimicrobial volatile compounds (orange EO and limonene) into soy and rapeseed nanoliposomes. These were then added to starch sodium caseinate film, forming dispersions. The antimicrobial activity of these films was not observed probably due to the encapsulation, which made difficult their release from the matrix (Jimenez et al., 2014). 

Abu, Diak O., Bani-Jaber, A., Amro, B., Jones, D., Andrews, G.P. The manufacture and characterization of casein films as novel tablet coatings. Food Bioprod. Process. 85(3), 284-290 (2007)... 

Khwaldia, K., Banon, S., Perez, C., Desobiy, S. Properties of sodium caseinate film-forming dispersions and films. J. Dairy Sci. 87, 2011-2016 (2004)... 

Mauer, L.J., Smith, D.E., Labuza, T.P. Water vapor permeability, mechanical, and stractural properties of edible -casein films. Int. Dairy J. 10, 353-358 (2000)... 

Dangaran, K.L., Cooke, P., Tomasula, P.M. The effect of protein particle size reduction on the physical properties of C02-precipitated casein films. J. Food Sci. 71, 196—201 (2006)... 

Fabra, M.J., Talens, P., Chiralt, A. Miaostructure and optical properties of sodium caseinate films containing oleic acid-beeswax mixtures. Food Hydrocolloids 23, 676-683 (2009)... 

Only few studies have been reported on the effect of the addition of cross-links on film properties. Chemical cross-linkers such as formaldehyde, glyoxal or glutaraldehyde were efficient in enhancing the maximum puncture force of films made from cotton seed proteins. Brault et al introduced cross-links between aromatic compounds (i.e. dityrosine) in caseinate films by exposing them to y-ionisation. Puncture strength and puncture deformation were both increased but this effect was very dependant of the ratio glycerol/protein. 

Protein, Protein structure. Physicochemical properties. Industrial application, Denaturation, Soy protein, Zein, Wheat protein. Casein, Films, Adhesives, Plastics, Blends, Composites, Green materials. Biodegradability... 

Biodegradable Material Obtained from Renewable Resource Plasticized Sodium Caseinate Films... 

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