Characterization of Proteolytic Enzymes from Thermophilic Lactic Acid Bacteria and Their Influence on Mozzarella Cheese Functional Properties

Principal Investigator:

Donald J. McMahon, Utah State University

Co-Investigators:

Jeffery Broadbent, Utah State University
Craig Oberg, Weber State University

Project Summary:

The purpose of this project is to control the functionality of Mozzarella cheese by understanding the role of starter culture proteolysis in the development of melting properties. This project will investigate (1) the diversity that exists in the proteolytic systems of important Thermophilic starter cultures, and (2) how these differences may influence Mozzarella cheese functionality. Strains of lactobacilli and Streptococcus thermophilus will be screened for proteinase activity, specificity toward as 1-casein (f 1-230) and their ability to degrade individual intact caseins. Strains found to represent distinct proteinase enzymes within lactobacilli species will then be added to cheese slurries and Mozzarella cheese to investigate the effect of these enzymes on proteolysis and cheese functionality. Knowing characteristics of starter culture proteolytic systems would provide a sound basis for starter culture selection; so that functionality can be customized to meet customer requirements. This information would then make it possible to develop starter culture systems for optimum manufacture of both full and lower fat Mozzarella cheese.

Publications:

Oberg, C. J., J. R. Broadbent, M. Strickland, and D. J. McMahon. 2000. Diversity in specificity of the extracellular proteinases in Lactobacillus helveticus and Lactobacillus delbruecki subsp. bulgaricus. Letters in Applied Microbiology (in review).

Oommen, B. S., D. J. McMahon, C. J. Oberg, J. R. Broadbent, and M. Strickland. 2001. Proteolytic specificity of Lactobacillus delbruecki subsp. bulgaricus influences functional properties of Mozzarella cheese. Journal of Dairy Science (in review).

Theses:

None

Published Abstract:

Oberg, C. J., J. R. Broadbent, M. Strickland, and D. J. McMahon. 2000. Diversity in specificity of the extracellular proteinases in Lactobacillus helveticus and Lactobacillus delbruecki subsp. bulgaricus. ASM Annual Meeting Program.

Presentations:

Oberg, C. J., J. R. Broadbent, M. Strickland, and D. J. McMahon. 2000. Diversity in specificity of the extracellular proteinases in Lactobacillus helveticus and Lactobacillus delbruecki subsp. bulgaricus. ASM Annual meeting. Los Angeles, CA. May 22-25, 2000.