ARS | Publication request: Utilization of supercritical carbon dioxide to produce milk protein fractions

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 27, 2009
Publication Date: July 13, 2009
Citation: Tomasula, P.M., Bonnaillie, L., Qi, P.X. 2009. Utilization of supercritical carbon dioxide to produce milk protein fractions [abstract]. ADSA Meeting Abstract.

Technical Abstract: The nutritional, functional and bioactive properties of the individual whey proteins are appreciated by health-conscious consumers, yet few methods have been developed to produce these proteins to satisfy demand. The methods that are available are relatively new technologies that have not been proven by development research and thus are unfamiliar to food processors. In our laboratory, we have shown that supercritical carbon dioxide (SCO2) at pressures, P, greater than 7.4 MPa, when injected into solutions containing whey protein isolate or whey protein concentrate is effective for production of enriched fractions of the whey proteins, alpha-lactalbumin (alpha-LA) and beta-lactoglobulin (beta-LG). Fractions containing 70 wt% of alpha-LA, in solid form, and 95 wt% beta-LG in a soluble liquid form uncontaminated with chemical or mineral additives have been obtained. We have also produced CO2-casein, a high calcium-containing casein and other food protein isolates using the process under high pressure conditions in the range from 4.1 MPa to 7.4 MPa. The process is not an extraction process but relies on the production of carbonic acid that results from hydrolysis of solubilized CO2. Separation of whole protein or the enriched whey fractions is achieved through manipulation of P, temperature, agitation rate, protein concentration, and holding time, all factors which have been shown to affect solvent pH, protein conformation, and yield. A continuous pilot plant process was developed to produce CO2 casein in kg quantities, and a large-scale process for production of the whey fractions is being designed. Both processes may be integrated to simultaneously produce CO2-casein and the enriched whey fractions from milk. Processes based on CO2 separation may be considered sustainable, because much of the CO2 may be recovered after separation has been achieved. Other advantages are that a relatively concentrated feed stream containing the whey proteins may be processed instead of a dilute feed stream and post-treatment washing is minimal compared to other methods. This presentation will focus on the casein and whey fractionation processes, as well as some of the properties of the proteins obtained from these processes.