Effect of Fat Removal on Cheese Microenvironment and Starter Culture Metabolism in Cheddar Cheese

Principal Investigators:  Jeffrey R. Broadbent, Utah State University

Co-Investigators:            Robert Ward, Utah State University

Project Summary:

Flavor development in bacterial-ripened cheese (e.g., Cheddar) is primary due to the action of lactic acid bacteria (LAB) and enzymes in the ripening curd. Knowledge of the mechanisms by which LAB affect cheese flavor has facilitated industry efforts to accelerate or intensify flavor development in many traditional cheese varieties. Unfortunately, empirical efforts to extend this information into low- fat cheese systems have not proved successful, and low-fat products continue to suffer from low intensity of desirable flavors and/or from pronounced off-flavor defects.

From a purely technological perspective, many of the flavor limitations in low-fat cheese might be overcome through the addition of dairy flavors or enzymes. However, these technologies add significant costs to the product, and low-fat cheeses already cost more to make than their full fat equivalents. Because consumers may not be willing to buy low-fat products if they cost a lot more than full fat cheese, solving flavor problems in low-fat cheese through dairy flavors or enzyme technologies is currently an unattractive option for the cheese industry. A more practical solution to flavor can likely be found through combining flavors or enzymes with more effective culture systems. Compared to dairy flavors or enzyme addition, culture technology is an inexpensive means to secure flavor development, and one that should therefore be further explored and optimized for industry to offset the price concerns associated with low-fat cheese products.

Flavor problems in low-fat products are most likely explained by a scenario wherein starter physiology itself (and thus overall metabolism) is altered by differences in the physico-chemical environment in ways that affect the production of flavor- and aroma-active metabolites. If this hypothesis is correct, efforts to develop effective culture systems for low-fat cheese will require more specific knowledge of how the cheese physico-chemical environment affects starter cell physiology. The goal of this study is to determine how Lactococcus lactis metabolism is affected by fat reduction and its concomitant changes in cheese make procedure impart on the cheese microenvironment (e.g., S/M ratio, lactate content, pH, etc.). Specific knowledge of the nature of these perturbations will provide basic information needed by industry to develop strains, through mutagenesis or other methods, that enhance flavor development in low-fat and nonfat Cheddar cheese.

Publications:

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Theses:

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Published Abstract:

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Presentations:

Broadbent, J.R. 2009. Effect of Fat Removal on Cheese Microenvironment and Starter Culture Metabolism in Cheddar Cheese. Western Dairy Center Annual Meeting. May 6, Utah State University, Logan.