Improvement of Mozzarella Cheese Functionality by Understanding Exopolysaccharide Production in Thermophilic Starter Cultures

Principal Investigator:

Dr. Jeffery Broadbent, Utah State University

Co-Investigators:

Dr. Donald J. McMahon, Utah State University
Dr. Craig Oberg, Weber State University

Project Summary:

Mozzarella cheese functionality is significantly affected by cheese moisture level, and increasing moisture content has been used to improve the melting properties of low fat Mozzarella cheese. Previous work by our group has shown that exopolysaccharide (EPS)-producing starter cultures can be used to significantly increase the moisture content of lower fat Mozzarella cheese. We have identified a culture, Streptococcus thermophilus MR-1C, that produces a large capsular EPS, and have shown that this capsule is involved in cheese moisture retention. Experiments are now underway to characterize the structure of the MR-1C EPS and isolate the genes that encode its biosynthesis. This project will provide basic information needed to understand the influence of EPS on cheese quality and functionality.

Publications:

Broadbent, J.R., D.L. Welker, J.A. Ahlgren, D.J. McMahon, and C. J. Oberg. 2001.
Comparative study of exopolysaccharide gene clusters in Streptococcus thermophilus. In final preparation.

Broadbent, J.R., D.J. McMahon, C.J. Oberg, and D. L. Welker. Use of exopolysaccharide-producing cultures to improve the functionality of low fat cheese. Int. Dairy J. (accepted)

Petersen, B. L., R.I. Dave, D.J. McMahon, C.J. Oberg, and J.R. Broadbent. 2000. Influence of capsular and ropy exopolysaccharide-producing Streptococcus thermophilus on Mozzarella cheese and cheese whey. J. Dairy Sci. 83: 1952-1956.

Oberg, C.J., J.R. Broadbent, and D.J. McMahon. 1998. Developments in Thermophilic starter cultures for cheese. Aust. J. Dairy Technol. 53:102-104. Low, D., Ahlgren, J.A., D. Horne, D.J. McMahon, C.J. Oberg, and J.R. Broadbent. 1998. Role of Streptococcus thermophilus MR-1C capsular exopolysaccharide in cheese moisture retention. Appl. Environ. Microbiol. 64:2147-2151

Theses:

Low, D. 1998. Influence of Streptococcus thermophilus MR-1C capsular exopolysaccharide on moisture level of low-fat Mozzarella cheese. MS thesis, Utah State University.

Published Abstract:

Peterson, B.L., R.I. Dave, D.J. McMahon, C.J. Oberg, and J.R. Broadbent.
Influence of capsular and ropy exopolysaccharide-producing Streptococcus thermophilus on Mozzarella cheese and cheese whey. J. Dairy Sci. 82(Suppl. 1):2.

Low, D., D.J. McMahon, C.J. Oberg, D. Horne, and J.R. Broadbent. 1997. Influence of Streptococcus thermophilus 10JC exopolysaccharide on the moisture content of low-fat Mozzarella cheese. J. Dairy Sci. 80(Suppl. 1):107.

Presentations:

Broadbent, J.R. 2000. Use of exopolysaccharide-producing cultures to improve the functionality of low fat cheese. Oral presentation at International Dairy Federation Symposium on Ripening and Quality of Cheeses. March 12-17, Banff, Canada.

Peterson, B.L., R.I. Dave, D.J. McMahon, C.J. Oberg, and J.R. Broadbent. 1999. Influence of capsular and ropy exopolysaccharide-producing Streptococcus thermophilus on Mozzarella cheese and cheese whey. Oral presentation at the Ann. Mtg. Amer. Dairy Sci. Assoc. June 20-23, Memphis, TN.

Broadbent, J.R. 1999. New Cultures. Invited oral presentation for the International Dairy Foods Association Cultured Dairy Products Conference. May 11-12, Milwaukee, WI.

Broadbent, J.R., D.J. McMahon, and C.J. Oberg. 1998. Practical Considerations in the Use of Exopolysaccharide-producing Cultures. Invited oral presentation for the Marschall/Rhodia, Inc. Italian and Specialty Cheese Conference, Sept. 16-17, Madison, WI.

Broadbent, J.R. 1998. Role of the Streptococcus thermophilus exopolysaccharide in cheese moisture retention. Invited oral presentation for Texel International. April 30, Dange, France.

Broadbent, J.R., D. Low, D., D.J. McMahon, C.J. Oberg, and J.A. Ahgren. 1998. Properties of a novel Streptococcus thermophilus capsular heteropolysaccharide. Poster presentation at the American Society for Microbiology's Conference on Streptococcal Genetics. April 26-29, Vichy, France.

Broadbent, J.R. 1997. EPS production in Streptococcus thermophilus: physiology, biochemistry, and genetics. Invited oral presentation for the Marschall/Rhône-Poulenc Italian and Specialty Cheese Conference, Sept. 17-19, Madison, WI.