Nutrition Commons^™

Characterization Of The Proteolytic System In Lactococcus Lactis Starter Cultures, Christina Beer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The proteolytic system of Lactococcus lactis starter cultures influences both flavor and the characteristic body and texture of cheese. The ability to further understand and control how different components of this proteolytic system work together to hydrolyze milk proteins would be of immense importance to the dairy industry.

The goal of this research was to characterize Lactococcus lactis subsp. lactis starter bacteria with varying prt operon compositions by proteinase specificity, aminopeptidase and lipase activities, growth, and influence on cheese flavor. By using a cheese slurry system, a statistical model to predict milk protein hydrolysis patterns was developed.

Lactococcus lactis subsp. …

Peptideaccumulation And Bitterness In Cheddar Cheese Made Using Single-Strain Lactococcus Lactis Starterswith Distinct Proteinase Specificities, Jeff Broadbent, M. Strickland, B. Weimer, M. E. Johnson, J. L. Steele

Nutrition, Dietetics, and Food Sciences Faculty Publications

This study investigated peptide accumulation and bitterness in reduced- and full-fat Cheddar cheeses that were manufactured with single-strain Lactococcus lactis starters that had distinct cell envelope proteinase specificities. Micellar electrokinetic capillary electrophoresis of aqueous cheese extracts detected three large peaks, designated O, P, and Q, that eluted with peptide standards and increased in area during cheese maturation in a pattern that was distinct for each starter. Regression analysis of bitter flavor scores from trained sensory panels and individual OQ peak areas suggested that peaks P and Q had a negative and positive correlation, respectively, to this defect. Then, HPLC, capillary …