Protein stabilisation

Figure 20.14 Preparation for DNA replication. At Least three proteins are involved DNA helicases disrupt hydrogen bonds between bases to allow the two strands to unwind single-strand DNA-binding proteins stabilise the unbound strands in preparation for base pairings DNA topoisomerase relaxes strain in the strands to facilitate polymerisation.

Behnke, O., Ammitzboll, T., lessen, H., Klokker, M., Nilhausen, K., Tranum-Jensen, H., et al. (1986) Non-specific binding of protein-stabilised gold sols as a source of error in immunocytochemistry. Eur. J. Cell Biol. 41, 326-338. 

Monahan, F.R., McClements, D.J., and Kinsella, J.E. 1993. Polymerisation of whey protein-stabilised emulsions. J. Agric. Food Chem. 41, 1826-1829. 

Tobias, J., Tracy, P.H. 1958. Observation on low fat dairy spreads. J. Dairy Sci. 41, 1117-1120. Tornberg, E., Ediriweera, N. 1987. Coalescence stability of protein-stabilised emulsions. In Food Emulsions and Foams (E. Dickinson, ed.), pp. 52-63, Royal Society of Chemistry, London. 

The FRAP method has been applied to the measurements of molecular lateral diffusion of molecules adsorbed at the interface of equilibrium common thin foam films and of black foam films [39-43], Initially Clark et al. reported FRAP measurement of surface diffusion of the fluorescence probe 5-N(octadecanoyl)aminofluorescein incorporated into foam films stabilised with NaDoS [39]. Then followed the measurements of protein-stabilised foam films where the protein was covalently labelled with fluorescein [40,41], Studies of FRAP measurements of surface lateral diffusion in equilibrium phospholipid common thin foam films and black foam films were also reported [42,43]. 

K. Gekko, S.N. Timasheff, Tliermodynamic and kinetic examination of protein stabilisation by glycerol. Biochemistry 20 (1981) 4677-4686. 

Pyne A, Chatterjee K, Suryanarayanan R. Solute crystallisation in mannitol-glycine systems. Implications on protein stabilisation in freeze-dried formulations. / Pharm Sci 2003 92(11) 2272-2283. 

Cosolvent effects such as this can be analysed from a thermodynamic point of view. Addition of cosolvents which cause preferential hydration of the protein stabilises the compact conformations of the protein because the cosolvent results in an increase in the free energy of the system. To reduce the free energy, the surface area of the protein is minimised. 

Anderson MA, Hatti-Kaul R. Protein stabilising effect of polyethyleneimine. J Biotechnology 1999 72(1-2) 21-31. 

Kiokias, S. and Bot, A., Temperature cycling stability of pre-heated acidified whey protein-stabilised o/w emulsion gels in relation to the internal surface area of the emulsion. Food Hydro colloids, 20, 246,... 

Gharsallaoui A, Saurel R, Chambin O et al. (2010) Utilisation of pectin coating to enhance spray-dry stability of pea protein-stabilised oil-in-water emulsions. Food Chemistry 122 447-454. 

Khouryieh H, Puli G, Williams K, Aramouni F. Effects of xanthan-locust bean gum mixtures on the physicochemical properties and oxidative stability of whey protein stabilised oil-in-water emulsions. Food Chem. 167 340-348,2015. 

In the spray-dried particles, microencapsulation efficiency was increased in bilayer emulsions (Fig. 2.23) and when using low-methoxylated pectin, oxidative stability of the encapsulated bioactive ingredient was decreased (Fig. 2.24). The process-induced shift in the oil droplet size was more pronounced in bilayer emulsions based on high methoxylated pectin than in bilayer emulsions based on low-methoxlyated pectin (Fig. 2.25). However, both emulsions were more stable than the protein-stabilised emulsions. Data from dilatational rheology show an... 

Taneja, A., Ye, A., Jones, J. R., Archer, R., Singh, H. (2013). Behaviour of oil droplets during spray drying of miUc-protein-stabilised oil-in-water emulsirms. International Dairy Journal, 28, 15-23. 

Flocculation by a bridging mechanism is well known for particle suspensions, where it is straightforward to adsorb polymers onto surfactant-free interfaces, but it is less commonly observed in emulsions. An exception is a protein-stabilised emulsion where the protein acts as a surfactant, but can cause bridging when there is incomplete surface coverage. 

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