|Li, Si-Quan - OHIO STATE UNIVERSITY|
|Balasubramaniam, V. - OHIO STATE UNIVERSITY|
|Lee, Young-Zoon - STOLLE MILK & BIOLOGICS|
|Bomser, Joshu - OHIO STATE UNIVERSITY|
|Schwartz, Steven - OHIO STATE UNIVERSITY|
|Dunne, C. Patrick - US ARMY NATICK CENTER|
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 8, 2005
Publication Date: March 15, 2006
Citation: Li, S., Zhang, H.Q., Balasubramaniam, V.M., Lee, Y., Bomser, J.A., Schwartz, S.J., Dunne, C. 2006. Comparison of effects of high pressure processing and heat treatment on immunoactivity of bovine milk immunoglobulin g in enriched soymilk under equivalent microbial inactivation levels. Journal of Agricultural and Food Chemistry. 54(3):739-746. Interpretive Summary: Immunoglobulin-rich foods may provide health benefits to consumers. To extend the refrigerated shelf-life of functional foods enriched with bovine immunoglobulin G, nonthermal alternatives such as high pressure processing (HPP) may offer advantages to thermal processing for microbial reduction. To evaluate the effects of HPP on immunoactivity of bovine IgG, a soymilk product enriched with milk protein concentrates, derived from dairy cows that were hyperimmunized with 26 human pathogens, were subjected to HPP or heat treatment. To achieve a 5-log reduction in inoculated E. coli 8739, HPP or heat treatment required were 345 MPa for 4 min at 30C or 70C for 20 s, respectively. To achieve a 5-log reduction in natural flora in the enriched soymilk, HPP or heat treatment needed were 552 MPa for 4 min at 30C or 78.2C for 120 s, respectively. At equivalent levels for a 5-log reduction in E. coli, HPP and heat treatment caused 25% and no detectable loss in bovine IgG activity, respectively. However, at equivalent levels for a 5-log reduction in natural flora, HPP and heat resulted in 65% and 85% loss of bovine IgG activity, respectively. Results of combined pressure-thermal kinetic studies of bovine milk IgG activity were provided to determine optimal process conditions to preserve product function.
Technical Abstract: Immunoglobulin G (IgG) is a protein that benefits consumers by providing stronger tolerance to microbial infections. IgG usually is added to foods such as cow’s milk or soymilk to serve as functional foods. IgG is sensitive to heat. Traditional canning will destroy IgG. New process needs to be developed to extend the shelf-life of IgG enriched products. This study evaluates the effects of high pressure processing (HPP) on the activity of bovine IgG in soymilk. To achieve a 5-log reduction in inoculated E. coli, HPP or heat treatment required were 345 MPa for 4 min at 30C or 70C for 20s. To achieve a 5-log reduction in natural flora in the enriched soymilk, HPP or heat treatment needed were 552 MPa for 4 min at 30C or 78.2C for 120 s. At equivalent levels for a 5-log reduction in E. coli, HPP caused 25% loss in IgG activity while heat caused no change. However, at equivalent levels for a 5-log reduction in natural flora, HPP resulted in 65% and while heat 85% loss of IgG activity. Both high pressure and heat are applicable to extend refrigerated shelf life.