Progress 10/01/08 to 09/30/12
Outputs
OUTPUTS: The research findings have been communicated to the U.S. and international dairy processing and ingredient industry. This has been accomplished through refereed publications, symposium presentations, presentations at industry short-courses, participation in expert panels, and presentations to individual food companies. This work has been presented at symposia at the American Dairy Science Association, Food Research Institute, and American Society for Microbiology annual meetings, as well as at the 18th Biennial Cheese Industry Conference in Logan Utah, the International Dairy Federations Cheese Ripening & Technology Symposium in Madison, WI and the International Conference on Functional Dairy Foods in Karnal India. The results have been incorporated into my presentations at two dairy industry short courses at the University of Wisconsin-Madison, specifically the Wisconsin Cheese Technology and Artisan Master Cheese-makers courses. The results have been communicated to the Dairy Management Inc. cheese expert panel via formal presentations and informal discussions. Finally, the results have been communicated directly to Kraft Inc., Danisco Inc, and Johnsonville Sausage. PARTICIPANTS: The research group participating in this work includes Willyn Tan, Mateo Budinich, Jee-Hwan Oh, Hui Cai, Dr. Scott Rankin, Dr. Mark Johnson, Dr. Jeff Broadbent and Dr. James Steele. This is a multi-disciplinary team that brings together the expertise required to address problems related to cheese flavor development. TARGET AUDIENCES: The target audience was researchers working on and with lactic acid bacteria in academic and industrial laboratories, as well as dairy industry personnel. Efforts to communicate with this group include refereed publications, as well as participation in national and international scientific meetings. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Growth of Lactobacillus casei ATCC 334, in a cheese ripening model system based upon a medium prepared from ripening Cheddar cheese (CCE) was evaluated at 37oC. Biochemical analysis and mass balance equations were utilized to determine substrate consumption patterns and products formed in CCE. The sequence of substrate utilization was determined to be: a portion of the phosphopeptide pool, lactose, galactose and citrate concurrently, galactose, and finally another portion of the phosphopeptide pool. The products formed included formate, acetate and D-lactate. This study provided valuable information on the biochemistry and physiology of Lb. casei ATCC 334 in a cheese model system. When similar growth studies in CCE were conducted at 8oC, the final cell densities were 10-100 fold lower than that observed at 37oC. Preliminary results suggested that the CCE was lacking an essential nutrient for growth at 8oC. Addition of milk fat into CCE enhanced the growth Lb. casei strains at 8oC. Therefore, CCE with 1% milk fat was used to examine strain-to-strain variations in growth and volatile compound formation in subsequent studies. Twenty-two Lb. casei strains were screened in CCE for their potential to serve as adjunct flavor cultures. The experiment was conducted under Cheddar cheese ripening condition (pH5.1, 3.1% NaCl, and 8oC). The attributes screened for were the ability to dominate the NSLAB microbiota, produce volatile flavor compounds, and hydrolyze bitter peptides. None of the Lb. casei strains examined degraded the model bitter peptide. Six strains exhibited growth parameters which suggested they are capable of dominating the NSLAB microbiota. Significant strain-specific variations were observed in 2,3-butanedione, phenylethanal, and phenylethanol accumulation. The use of culture adjuncts that reduce the level of phenylethanal would likely result in Cheddar cheeses with a reduced rosy note. The results of this study provided a starting point for the rational selection of culture adjuncts to control cheese flavor development in Cheddar cheese. This study focused on how varying the composition of a cheese ripening model system affects the growth and metabolism of five Lb. casei strains. The conditions varied included salt (1.2% and 4.8%), lactate (2.7% and 4.3%), and lactose (0.2% and 1.0%). CCE was utilized as the growth media, and a ten week incubation was conducted at 8oC pH 5.2 in the absence of oxygen. At select time points, organic acids and volatiles were quantified. These results suggested that two of the strains may positively affect flavor development in low sodium cheeses. This study demonstrates that controlling the non-starter lactic acid bacteria microbiota at the strain level is essential for controlling flavor development in low sodium Cheddar cheeses.
Publications
- Tan, W.S. M.F. Budinich et al. 2012. Growth of Lactobacillus casei at 8oC in Cheddar cheese extract requires exogenous fatty acids. J. Dairy Sci. 95:1680.
- Cai, H., W. Tan, M. Budinich, M. Drake, S. Rankin, and J.L. Steele. 2013. Growth and production of volatile compounds by Lactobacillus casei in Cheddar cheese extract under Cheddar cheese ripening conditions. Manuscript in preparation.
- Oh, J-H, M.F. Budinich, J.R. Broadbent, and J.L. Steele. 2013. The influence of salt, lactate, and lactose concentrations on the growth and metabolism of strains of Lactobacillus casei. Manuscript in preparation.
|
Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: The research findings have been communicated to the U.S. and international dairy processing and ingredient industry. This has been accomplished through presentations at the American Dairy Science Association annual meeting, "Growth and metabolism of Lactobacillus casei in a ripening Cheddar cheese model varying salt, lactate, and lactose concentrations"; and the 10th symposium on lactic acid bacteria, "Evaluation of Lactobacillus casei strains in a model cheese ripening system". Additionally, these results have been presented to two companies, Kraft Inc. and Danisco USA at industry requested presentations, as well as at short courses for dairy industry personnel sponsored by the Department of Food Science. PARTICIPANTS: The research group participating in this study includes Willyn Tan, Mateo Budinich, Jee-Hwan Oh, Hui Cai, Dr. Scott Rankin, Dr. Mark Johnson, Dr. Jeff Broadbent and Dr. James Steele. This is a multi-disciplinary team that brings together the expertise required to address problems related cheese flavor development. TARGET AUDIENCES: Our target audience is researchers working on and with lactic acid bacteria in academic and industrial laboratories, as well as dairy industry personnel. Efforts to communicate with this group include refereed publications, as well as, participation in national and international scientific meetings. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Growth of Lactobacillus paracasei ATCC 334, in a cheese ripening model system based upon a medium prepared from ripening Cheddar cheese (CCE) was evaluated. Lb. paracasei ATCC 334 grows in CCE made from cheese ripened for 2 (2mCCE), 6 (6mCCE) and 8 (8mCCE) months, to final cell densities of 5.9x108, 1.2 x108, and 2.1x107 CFU/mL, respectively. Biochemical analysis and mass balance equations were utilized to determine substrate consumption patterns and products formed in 2mCCE. The products formed included formate, acetate and D-lactate. These data allowed us to identify the pathways likely utilized and initiate metabolic flux analysis. The production of volatiles during growth of Lb. paracasei ATCC 334 in 8mCCE was monitored to evaluate the metabolic pathways utilized by Lb. paracasei during the later stages of ripening Cheddar cheese. The two volatiles detected at high levels were ethanol and acetate. The remaining detected volatiles are present in significantly lower amounts and likely result from amino acid, pyruvate and acetyl-CoA metabolism. Carbon balance of galactose, lactose, citrate and phosphoserine/phosphoserine containing peptides in terms of D-lactate, acetate and formate are in agreement with the amounts of substrates observed in 2mCCE, however this was not the case for 6mCCE and 8mCCE, suggesting that additional energy sources are utilized during growth of Lb. paracasei ATCC 334 in these CCEs. This study provides valuable information on the biochemistry and physiology of Lb. paracasei ATCC 334 in a extract cheese model system.
Publications
- Budinich, M.F., I. Diaz-Muniz, H. Cai, S.A. Rankin, J.R. Broadbent and J.L. Steele. 2011. Growth of Lactobacillus paracasei ATCC 334 in a cheese model system: A biochemical approach. J. Dairy Sci. 94:5263-5277.
|
Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: The research findings have been communicated to the U.S. dairy processing and ingredient industry. This has been accomplished through symposium presentations entitled "The influence of salt-in-the-moisture on starter and non-starter lactic acid bacteria", "The microbiology of cheese", and "Technical challenges and strategies to achieve sodium reductions goals: dairy" at the American Dairy Science Association, American Society for Microbiology, and Food Research Institute 2010 annual meetings, as well as, via my service on the Dairy Management Inc. Low-fat cheese expert panel and participation in short courses for dairy industry personnel. PARTICIPANTS: The research group participating in this study includes Willyn Tan, Mateo Budinich, Jee-Hwan Oh, Hui Cai, Dr. Scott Rankin, Dr. Mark Johnson, Dr. Jeff Broadbent and Dr. James Steele. This is a multi-disciplinary team that brings together the expertise required to address problems related cheese flavor development. TARGET AUDIENCES: My target audience is researchers working on and with lactic acid bacteria in academic and industrial laboratories, as well as dairy industry personnel. Efforts to communicate with this group include refereed publications, as well as, participation in national and international scientific meetings. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
This years research focused on how varying the composition of a cheese ripening model system affects the growth and metabolism of Lactobacillus casei M36, UW1, UW4, 32G, and 12A. The conditions varied included salt (1.2% and 4.8%), lactate (2.7% and 4.3%), and lactose (0.2% and 1.0%. The Cheddar cheese ripening model system employed a water extract of Cheddar cheese, Cheddar cheese extract (CCE), as the growth media, and ten week incubation was conducted at 8oC and pH 5.2 in the absence of oxygen. During this ten week long period there were 12 time points in which the culture was enumerated and the pH was determined. At select time points, organic acids were quantified by High Performance Liquid Chromatography (HPLC). Volatiles formed were quantified by Gas Chromatography (GC). This study suggest that UW4 and M36 strains may affect flavor enhancement in low sodium and reduced fat cheese. UW4 strain was able to reduce rosy flavor and M36 strain increased buttery and sulfur flavor during cheese ripening in low sodium condition. Both UW4 and M36 did not produce significant amount of acetic acid but growth rate were faster than other strains. Phenylalanine catabolites production of these two strains are also inhibited by addition of salt. This study demonstrates that controlling the non-starter lactic acid bacteria microbiota (NSLAB) is essential for controlling flavor development in low sodium Cheddar cheeses.
Publications
- Oh, J-H, M.F. Budinich, J.R. Broadbent, and J.L. Steele. 2010. The influence of salt, lactate, and lactose concentrations on the growth and metabolism of strains of Lactobacillus casei. In preparation
|
Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: The research findings have been communicated to the U.S. dairy processing and ingredient industry. This has been accomplished through refereed publications, a symposium presentation entitled "The challenge of controlling the microbiota of cheese" at the 18th Biennial Cheese Industry Conference, presentations to Kraft Inc. and MillerCoors, an oral presentations at the annual meeting of the American Dairy Science Association, as well as, via my service on the Dairy Management Inc. Low-fat cheese expert panel. PARTICIPANTS: The research group participating in this study includes Willyn Tan, Mateo Budinich, Jee-Hwan Oh, Hui Cai, Dr. Scott Rankin, Dr. Mark Johnson, Dr. Jeff Broadbent and Dr. James Steele. This is a multi-disciplinary team that brings together the expertise required to address problems related cheese flavor development. TARGET AUDIENCES: My target audience is researchers working on and with lactic acid bacteria in academic and industrial laboratories. Efforts to communicate with this group include refereed publications, as well as, participation in national and international scientific meetings. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The first outcome was a study on the growth of Lb. casei ATCC 334, in a cheese ripening model system based upon a media prepared from ripening Cheddar cheese (CCE) was evaluated. ATCC 334 was determined to grow in CCE at 37oC made from cheese ripened for 2 (2mCCE), 6 (6mCCE) and 8 (8mCCE) months. The sequence of substrate utilization was determined to be: a portion of the phosphopeptide pool, lactose, galactose and citrate concurrently, galactose, and finally another portion of the phosphopeptide pool. The products formed included formate, acetate and D-lactate. The availability of this data allowed us to identify the pathways likely utilized and initiate metabolic flux analysis. This study provided valuable information on the biochemistry and physiology of ATCC 334 in a cheese extract model system. Unfortunately, when similar growth studies in 4mCCE were conducted at 8oC, the final cell densities were 10-100 fold lower than that observed at 37oC. In comparison, when growth experiments were done at 8 and 37oC in MRS broth, no significant differences were observed in the final cell densities obtained. These results suggested that 4mCCE was lacking an essential nutrient for growth of Lb. casei strains in 4mCCE at 8oC to the levels observed at 37oC. Addition of milk fat into 4mCCE enhanced the growth Lb. casei strains at 8oC, and changes in cytoplasmic membrane fatty acid composition were observed. Therefore, CCE with 1% milk fat was used to examine strain-to-strain variations in growth and volatile compound formation. Twenty-two Lb. casei strains were screened in a model system for attributes likely to influence their potential to serve as adjunct cultures for the manufacture of Cheddar cheese. The model system used was 4-month old Cheddar cheese extract supplemented with citrate (4mCCE-cit) and 1% milk fat. The experiment was conducted under Cheddar cheese ripening condition (pH5.1, 3.1% NaCl, and 8oC). The attributes screened for were the ability to dominate the NSLAB microbiota, produce volatile flavor compounds, and hydrolyze bitter peptides. None of the Lb. casei strains examined could degrade the model bitter peptide beta-CN(f193-209) under the condition examined. Six strains (A2-309, CRF28, L9, M36, UW1 and UW4) exhibited growth parameters in the model system, relatively short lag phase, rapid growth rates, and high final cell densities, likely to be associated with the ability to dominate the NSLAB microbiota of Cheddar cheese. Significant increases in 2,3-butanedione accumulation was observed with seven of the Lb. casei strains examined; 2,3-butanedione is strongly associated with the beneficial buttery note in young Cheddar cheese. Significant decreases in phenylethanal concentrations were observed for nine strains and significant increases in phenylethanol concentrations were also observed for nine strains. The use of culture adjuncts that reduce the level of phenylethanal would likely result in Cheddar cheese with a reduced rosy note. The results of this study provided a starting point for the rational selection of culture adjuncts to control cheese flavor development in Cheddar cheese.
Publications
- Budinich, M., I. Diaz-Muniz, H. Cai, J.R. Broadbent, S.A. Rankin, and J.L. Steele. 2010. Growth of Lactobacillus casei ATCC 334 in a cheese model system: A biochemical approach. Submitted
- Tan, W.S. M.F. Budinich, R. Ward, J.R. Broadbent, and J.L. Steele. 2010. Growth of Lactobacillus casei at 8oC in Cheddar cheese extract requires supplementation. Manuscript in preparation.
- Cai, H., W. Tan, M. Budinich, M. Drake, S. Rankin, and J.L. Steele. 2010. Growth and production of volatile compounds by Lactobacillus casei in Cheddar cheese extract under Cheddar cheese ripening conditions. Manuscript in preparation.
|
Progress 10/01/08 to 12/31/08
Outputs
OUTPUTS: Spontaneous streptomycin- and rifampicin-resistant mutants of Lactobacillus casei ATCC 334 have been isolated. These isolated have been confirmed as Lactobacillus casei via sequencing of the 16S gene. PARTICIPANTS: Willyn Tan is a graduate student in the Department of Food Science working towards a Masters degree. She is learning basic microbiology skills that will prepare her to work in the food industry. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
These mutants will be used to follow the growth of Lactobacillus casei ATCC 334 in ripening cheese. The antibiotic-resistance markers are essential as a background level of wild Lactobacillus casei are expected to be present in all ripening Cheddar cheese.
Publications
- No publications reported this period
|
|