Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/30/2005
Publication Date: 8/2/2005
Citation: Qi, P.X., Cooke, P.H., Tomasula, P.M., Wickham, E.D. 2005. Characterization of casein-based films by transmission electron microscopy. (Abstract). 230th ACS National Meeting. Paper No. AGFD 104. Interpretive Summary: n/a
Technical Abstract: Edible films, made from milk proteins such as casein, offer a potential alternative to nonbiodegradable coatings and films currently used to enhance the quality or extend the shelf life of foods. Bovine casein obtained by a novel process using high pressure CO2 is of particular interest not only because the process itself is environmentally benign, it also presents a new opportunity for more efficient utilization of milk. We have demonstrated previously that films based on CO2 precipitated casein possess higher hydrophobicity resulting in lower water solubility compared to films made from commercial calcium caseinate. In this work, we studied CO2 casein films using Transmission Electron Microscopy (TEM) and compared them with films derived from acid casein, sodium caseinate and calcium caseinate to gain insight on differences in film properties, particularly water solubility, caused by different processing methods. The results showed alteration in the structure of casein micelles in CO2 casein which appears similar to that of acid casein, which is insoluble in water, in many respects. We postulate that the large aggregates shown in the TEM images of CO2 casein film relative to the smaller aggregates seen for calcium caseinate film may be due to changes in protein-protein interactions on the micellar level and may thus be attributable to the observed characteristics, such as water solubility.