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Transglutaminase-induced crosslinking of sodium caseinate stabilized oil droplets in oil-in-water emulsions
- Zeeb, Benjamin, Beicht, Johanna, Eisele, Thomas, Gibis, Monika, Fischer, Lutz, Weiss, Jochen
- Food research international 2013 v.54 no.2 pp. 1712-1721
- crosslinking, droplets, emulsions, gelation, gels, oils, probability, protein content, protein-glutamine gamma-glutamyltransferase, sodium caseinate, texture
- The present study established a better understanding of the gelling mechanism of a crosslinking enzyme (microbial transglutaminase) added to sodium caseinate (Na-Cas)-stabilized oil-in-water emulsions varying in droplet concentration and protein content. First, fine dispersed emulsions (5–60% (w/w) Miglyol; 2, 5, and 8% (w/w) aqueous Na-Cas) were prepared using a high pressure homogenizer. Second, microbial transglutaminase was added to Na-Cas-stabilized emulsions (37°C, 15h, pH6.8) to initiate Na-Cas crosslinking. Texture profile analysis and rheological measurements indicated that at low protein concentrations droplet–droplet inter-crosslinking occurred above a critical oil volume concentration (coil>0.6) yielding particle gels. There, strength of the droplet networks formed depended on oil droplet. At high Na-Cas contents, crosslinking of excess Na-Cas in the aqueous phase occurred and particle-filled continuous gels were formed instead. Theoretical calculations of mean distances between droplets and diffusion coefficients of droplets indicate that a certain probability of contact was required for microbial transglutaminase to be able to crosslink droplets.