Effect of alkaline pH values on physical and functional properties of edible films made from calcium caseinates

Authors: Plumier, Benjamin; AKKURT, SERIFE - Oak Ridge Institute For Science And Education (ORISE); Bonnaillie, Laetitia; Yee, Winnie; Ashby, Richard - Rick; McAnulty, Michael; Garcia, Rafael; Renye, John; Tomasula, Peggy

Submitted to: International Dairy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/26/2023
Publication Date: 12/3/2023
Citation: Plumier, B.M., Akkurt, S., Bonnaillie, L., Yee, W.C., Ashby, R.D., McAnulty, M.J., Garcia, R.A., Renye Jr, J.A., Tomasula, M.M. 2023. Effect of alkaline pH values on physical and functional properties of edible films made from calcium caseinates. International Dairy Journal. 151:105851. https://doi.org/10.1016/j.idairyj.2023.105851.
DOI: https://doi.org/10.1016/j.idairyj.2023.105851

Interpretive Summary: Flexible films are important in food storage, providing physical barriers to oxygen and water; e.g., but many are made with nonrenewable materials, and it would be beneficial to replace them with renewable, cheaper, and edible options. Milk based proteins can be used to create films but their strength and water resistance, doesn't match that of the nonrenewable materials. Initial research in our laboratory showed that increases in the pH of the formulations used to prepare the films affects the arrangement of the molecules in the films and can improve their performance. This paper explores the physical properties of two milk-based film formulations and their change with increased pH, as well as storage time and demonstrates improvements that can be made to film production.

Technical Abstract: Flexible films are important in food packaging, delivery, and preservation of food products. Plastic-based films are used for this task, but they are typically oil based, non-renewable, non-biodegradable, and non-edible. Milk based films have the potential to be renewable, edible, and may provide a lower cost option to replace plastic films. Research into milk-based films, particularly caseinates, has been conducted, but there is still a need to find formulations that have superior physical properties and can be made with cheaper materials. Our earlier research had suggested that pH modification of the film solution into alkaline conditions could improve film properties and mitigate the hydrophilic nature of milk-based proteins. Additionally, use of nonfat dry milk as a substitute for casein in formulations could produce films more cheaply. The objective of this study was to investigate the effect of increased pH on various physical properties of fresh and aged calcium caseinate and films with and without the addition of nonfat dry milk. Results include a wide range of data on the suitability of caseinate based films with and without dry milk. The data indicate that calcium caseinate films with modified pH have many beneficial properties and are promising candidates for food applications.