Improvement of Cheddar Cheese Quality Through Identification and Characterization of Microbial Enzymes Responsible for the Production or Degradation of Bitter Peptides in Cheese

Principal Investigator:

Dr. Jeffery R. Broadbent, Utah State University

Co-Investigators:

Dr. Charlotte Brennand, Utah State University
Dr. James L. Steele, University of Wisconsin-Madison
Dr. Mark E. Johnson, Center for Dairy Research

Project Summary:

Bitterness is a significant problem in Cheddar cheese, and this defect is particularly common in low-fat cheeses. Bitterness has been a problem in cheese for decades, but modern consumer preference for mild-flavored Cheddar has lent greater significance to the impact of bitterness on dairy economics. Bitterness is caused by the accumulation of hydrophobic peptides produced by some starter bacteria and chymosin. Starter proteinase specificity is the primary determinant in whether or not a starter culture produces bitter peptides. Fortunately, bitter peptides produced by chymosin and starter bacteria can by degraded by intracellular peptidases from starters and adjunct bacteria, but the relative contribution of individual peptidases to these reactions remains unknown. This project will identify and characterize microbial enzymes responsible for the production or degradation of bitter peptides in cheese. Results from the study will facilitate industry efforts to understand and control flavor development in Cheddar cheese by providing new strategies to identify or develop starter systems which eliminate or control bitter flavor defect in full and low-fat Cheddar cheese.

Publications:

Broadbent, J.R., M. Barnes, C. Brennand, M. Strickland, K. Houck, and M.E. Johnson. 2001. Contribution of Lactococcus lactis cell envelope proteinase specificity to peptide accumulation and bitterness in Cheddar cheese. In final preparation.

Steele, J.L. 2001. Cloning and characterization of a post-prolyl endopeptidase from Lactobacillus helveticus CNRZ32. In final preparation.

Christensen, J.E., E.G. Dudley, and J.R. Pederson, J.L. Steele. 1999. Peptidases and amino acid catabolism in lactic acid bacteria. Antonie van Leeuwenhoek 76:217-246.

Steele, J.L., M.E. Johnson, J.R. Broadbent, and B.C. Weimer. 1998. Starter culture attributes which affect cheese flavor development, pp. 157-170. In, Proc. LACTIC '97 conference, Which strains? For which products? Johnson, M.E., J.L. Steele, J. Broadbent, and B.C. Weimer. 1998. Manufacture of Gouda and flavor development in reduced-fat Cheddar cheese. Aust. J. Dairy Technol. 53:67-69.

Broadbent, J.R., M. Strickland, B. Weimer, M.E. Johnson, and J.L. Steele. 1998. Peptide accumulation and bitterness in Cheddar cheese made using single-strain Lactococcus lactis starters with distinct proteinase specificities. J. Dairy Sci. 81:327-337.

Theses:

None

Published Abstract:

None

Presentations:

Broadbent, J.R. Role of lactic acid bacteria in cheese flavor development. Invited oral presentation for special ADSA pre-meeting workshop on the basics of flavor development in cheese. Sponsored by the American Dairy Science Association and Rhodia, Inc. July 24, Baltimore, MD.

Steele, J.L. 1999. Peptidases and amino acid catabolism. Invited oral presentation for the symposium on Dairy Flavors and Biotechnology. IFT Annual Meeting, July.

Steele, J.L. 1999. Peptidases and amino acid catabolism. Invited oral presentation for the Sixth Symposium on Lactic Acid Bacteria. September, The Netherlands.

Broadbent, J.R. 1999. Cheese curing and flavor development. Invited oral presentation for the 15th Cheese Making Short Course. February 9-11, Utah State University, Logan.

Broadbent, J.R. 1998. How starter bacteria direct cheese flavor development. Invited oral presentation for the 13th Biennial Cheese Conference. Aug. 10-12, Utah State University.

Broadbent, J.R. 1998. Influence of Lactococcus lactis starter bacteria on peptide accumulation and bitterness in Cheddar cheese. Invited oral presentation for Texel International. April 30, Dange, France.

Broadbent, J.R. 1998. Cheese curing and flavor development. Invited oral presentation for the 14th Cheese Making Short Course. March 26-28, Utah State University, Logan.

Broadbent, J.R. 1997. Influence of starter bacteria on peptide accumulation and bitterness in Cheddar cheese. Invited oral presentation for the National Cheese Technology Forum sponsored by Dairy Management, Inc., Dec. 9-10. Chicago.