CHEESE MOISTURE TESTING IMPROVEMENT

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0217989
• Project Start Date: Jul 1, 2009
• Project End Date: Jun 30, 2011
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIV OF WISCONSIN
21 N PARK ST STE 6401
MADISON,WI 53715-1218

Performing Department
Food Science

Non Technical Summary
Moisture in cheese is important from a regulatory, economic, and functional viewpoint. The manufacture of cheese is dehydration process and is vastly complicated as compared to simple moisture removal process from milk like spray drying. It is the goal of cheese making to retain some moisture to achieve the desired texture and allow for controlled flavor development by the beneficial bacteria. The removal of moisture from milk in cheese making then has many process and compositional manipulations that are successful in providing a cheese near the desired moisture. However, precision of the moisture removal is of great importance as a one percent change in cheese moisture, for example, a 38% versus a 39% moisture cheddar cheese, represents about $0.077 USD per kg loss in revenue. This is based on recent average commodity market pricing from 2003 to the present. The profit loss is considered very significant due to cheese sales margins. It is hypothesized there are errors in determining moisture in cheese. The goal of this study is to find factors and develop procedures to diminish erroneous cheese moisture testing relative to chemical composition, rheological behavior, sample preparation, and analytical methodology. An improved and less compositional-dependent cheese moisture method would be of great advantage to the agriculture producers of the State of Wisconsin. The proportion of total cheese produced in the state by individual farmers and farmer owned cooperatives is about 35%. Therefore, proper accounting of dairy solids would enhance economic opportunities for agricultural producers since an erroneous over estimation of moisture determination would be disadvantageous to the seller. The official test, which uses vacuum and heat to dry the sample, needs the cheese sample to be a wholly intact or blended. During the test procedure, there is the inevitability of being heated at a high temperature during maximum Maillard browning reaction rates. The resultant condensation of reducing sugars with terminus amines will release water and hence the analysis will over report the moisture content. This hypothesis has recently gained more importance due to compositional variation as the result of the vast expansion commercial product offerings. Recent advances in microbial starters or commercial natural cheese manufacture or both may retain more lactose or galactose as compared to traditional cheese counterpart. Lactose and galactose are known to significantly react with protein while heated and give off water. At the time of the development and refinement of the analytical moisture method, residual lactose and galactose in cheese was not pervasive throughout the industry. Another source of significant error relates to sample melt and textural variation. There would be situations of sample presentation at the beginning of the analytical procedure where heat and low pressure will cause the sample to splatter from the uncontrolled vaporization of water and other volatiles. This phenomenon will cause physical removal of sample from the testing pan.

Animal Health Component

75%

Research Effort Categories

Basic

25%

Applied

75%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
501	3430	2000	100%

Knowledge Area
501 - New and Improved Food Processing Technologies;

Subject Of Investigation
3430 - Cheese;

Field Of Science
2000 - Chemistry;

Keywords

cheese

cheese moisture

lactose

galactose

maillard browning

vacuum oven

cheese melt

reducing sugar

moisture

cheddar cheese

process cheese

browning

Goals / Objectives
The goal of this study is to find factors and develop procedures to diminish erroneous cheese moisture testing relative to chemical composition, rheological behavior, sample preparation, and analytical methodology. The analysis uses heat and vacuum to dry the cheese. There may be condensation of reducing sugars with terminus amines will release water. The output of the project will be to provide a statistical model supporting additional methodology for improving the accuracy of the cheese moisture test. This will part of an all ready existing outreach program of the principle investigator with the citizens who would most benefit from the information. There are significant financial impacts relative to moisture. An improved cheese moisture method would be an advantage to the agriculture producers. For example, a one percent change in Cheddar cheese moisture represents about $0.077 USD per kg loss in revenue. The proportion of total cheese produced in the state by individual farmers and farmer owned cooperatives is 35%, +/-5. Moisture variation may have significant effect upon measured performance of the cheese. Some typical characteristics of cheese in which moisture can be important in moderating are: body, mouth feel, flavor release in the mouth, shelf life, melt, and flavor development during fermentation. Another critical aspect of cheese moisture control relates to limiting microbiological spore germination during out of refrigeration handling abuse. The organism of most concern is C. Botulium and its associated lethal toxin. The first phase of the study will involve screening cheeses as a Design of Experiment in order to generate a statistical model. As significant factors are indentified, more controlled experimental designs, for example ANOVA, will be done in order to further refine the magnitude of the factors that make up the model. A requirement of the test is that the cheese needs to be a wholly intact or blended cheese sample. However, there is a potential that the sample could experience partial pyrolytic decomposition and volatize true solids. This would result in an erroneous high result of moisture. This hypothesis has gained more importance in recent history due to vast compositional and textural variation of cheese as the result of the expanded commercial product offerings. Recent advances in microbial starters or commercial natural cheese manufacture or both may retain more lactose or galactose as compared to traditional cheese counterpart. Lactose and galactose are known to significantly react with protein while heated and give off water. At the time of the development and refinement of the analytical moisture method, residual lactose and galactose in cheese was not pervasive throughout the industry. Another source of significant error relates to sample melt and textural variation. The determination of moisture with the use of secondary methods such as near infrared spectroscopy or microwave ovens is wide spread. However, precision in the chemical analysis is vital to having predictive correlations in the secondary method, so additional quantitative steps to the standard method would be justified.

Project Methods
The expression of result from the moisture test is the difference of the weight loss of the dried sample after conducting the moisture test divided the weight of sample before conducting the moisture test. Comparison of new experimental methodologies will be reported as percent moisture as outline in the standard test or as a percentage difference result in percent moisture when two or more methodologies are compared. An improved method of moisture determination would be easy adopted by the industry even with a few additional steps added to the procedure. This is based on the widespread use of secondary methods such as infrared spectroscopy or microwave ovens that decreases significantly the need for the primary method using a vacuum oven. The sugar found in milk is almost entirely lactose and is a reducing sugar. There is widespread use of starters in natural cheese that are unable to metabolize the galactose sugar of lactose. Galactose will be involved in browning reactions very similarly to lactose. There are also novel nature cheese manufacturing methods that result in higher levels of lactose as compared to traditional manufacture. Process American cheese will typically have more reducing sugars and more variation in melt behaviors than natural cheese. There are more cheese varieties being offered in the marketplace with a larger spectrum of melting properties. Melting of cheese could then influence moisture test accuracy. A cheese that either melts too quickly or too slowly would not test well using the current moisture method. Increased firmness of the cheese could also change the melt of the cheese. There may be certain melt characters that will allow the cheese to fuse during the initial heating that may cause browning. The method for moisture determination in whey utilizes the same vacuum oven configuration as used for cheese moisture determination, however, the oven temperature is set at 65 degrees C for 16 hrs. It would be possible that lower temperatures would cause less browning. The use of pre-drying of the sample before introduction to the standard method test should provide samples with a low rate of pyrolytic decomposition. It must be assumed that loss of volatile components from a sample would follow the same thermodynamic process of evaporation with either the standard method or with a pre-drying treatment. Any significant difference result found in the comparisons would then be the result of pyrolytic decomposition. The standard test allows the use of either a disposable aluminum dish with fiberglass or equivalent pads as a cover or reusable aluminum moisture pan with insert covers. Either pan type is sufficient as long as spatter is controlled from rapid vaporization under vacuum.

Progress 07/01/09 to 06/30/11

Outputs
OUTPUTS: Accurate measurement of moisture in cheese is important to maximize yield and ensure economic parity. Official methods determine moisture based on the mass lost due to the thermal volatilization of available water. Because cheese is a chemically complex and variable medium, there is a potential that additional volatile compounds may be created during analytical moisture determination. Maillard browning and other various thermally catalyzed reactions may alter the final mass after drying. The residual sugars lactose and galactose are two components in cheese that may be natively present at varying levels and may participate in reactions capable of artificially elevating moisture determination. Novel cheese manufacturing methods may result in higher levels of lactose and galactose as compared to the traditional manufacturing methods. The objective of this study was to examine the effects of residual lactose and galactose on cheese moisture determination. In this study, Medium Cheddar and LMPS Mozzarella were prepared with up to 5% added lactose or galactose and were subjected to either vacuum oven or microwave-based moisture tests. In general, overestimated moisture content increased with increasing sugar level, establishing the need to consider residual sugar in cheese as a means of more accurately determining moisture in cheese. PARTICIPANTS: Lee, Hanna: graduate student; Rankin, S.A.: collaborator; Milani, F.X.: PI TARGET AUDIENCES: The target audience is cheese makers, of which there was just over 10 billion pounds of cheese produced in the USA in 2010. In the state of Wisconsin, about 32% of cheese made is manufactured by farmer-owned cooperatives. Therefore, economic losses identified with this project would impact farmers directly. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Moisture content of Cheddar and Mozzarella had a significant effect (P<0.05) as a function of added sugar type, sugar level, method type, sugar type vs. sugar level and sugar type vs. method type. In general, overestimated moisture content increased with increasing sugar level, establishing the need to consider residual sugar in cheese as a means of more accurately determining moisture in cheese. It was also noted the samples with reducing sugars displayed substantial dark brown color after the moisture analysis as compared to minimal color change for the control. Further examination of Maillard browning reaction and evolution of composition-dependent volatiles will be performed.

Publications

• Lee, H., F.X. Milani, and S.A. Rankin. 2011. Effects of residual lactose and galactose on cheese moisture determination. Abstract to: American Dairy Science Association annual meeting, New Orleans, LA, July 2011.

Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: The objective of the research is to identify sources of error and recommend procedural adjustments in the analytical determination of moisture in cheese. We have found evidence there are errors in determining moisture in some cheeses that are economically important. During the first year we conducted a marketplace survey of representative cheeses of significance. There appears to be cheeses that exhibit higher moisture results using the standard method alone as compared to conducting the standard moisture test with a prior pre-drying step. It appears to be at least conditional that residual carbohydrate be present in the cheese. However, there may be additional factors that need to be determined. The goal of this study is to find factors and develop procedures to diminish erroneous cheese moisture testing relative to chemical composition, sample preparation, and analytical methodology. PARTICIPANTS: Louisa Hays, UW-Madison, Hanna Lee, UW-Madison TARGET AUDIENCES: The appropriate audience who would benefit from the expected results of this research would be private companies, co-operative for profit organizations, commercial laboratories, and governmental agencies. Public notification would be through a peer reviewed journal and scientific organizations yearly gatherings such as American Dairy Science Association and Association of Official Analytical Chemist. There are also several dairy related trade publications which service entities that would benefit from the expected results. Examples would be Dairy Field, Food Technology, Hordes Dairyman, and The Pipeline. With the discovery of methodologies for improvement, the economic impact could be estimated once the magnitude of error is determined as a result of this study for each cheese classification. This would most likely be supported by the industry and regulatory agencies if the impact were both economically and scientifically significant. Analytical methods that are part of the regulation for a defined food, such as cheese, will need to follow administrative approval process and typically involves multiple laboratories before becoming an official method. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Low moisture part-skim Mozzarella had a significant moisture test difference, as defined by adding a pre-drying step prior to conduction the standard moisture test, which indicates a reported actual standard moisture test adding 0.53% to the reported value. There is evidence of the hypothesis that the error in moisture determination appears to be conditional that residual carbohydrate be present in some cheeses. However, there may be additional factors that need to be determined, as it has been found that not all cheeses with residual carbohydrate present the erroneous moisture result as indicated by the result found with reduced fat cheddar cheese. Other results gather to date indicate there are optimal methods for pre-drying cheese samples as indicated by the statistical reproducibility of various method improvements. Preliminary modeling of added lactose or galactose to simple commutated cheese model cheese systems were inconclusive and had a high degree of variability when determining the moisture. This would support the reasoning that we need to use a bench to cheese model system that is closer to actual cheese making procedures and resultant product as that model would allow added amounts of lactose or galactose to contact the protein similar to native milk.

Publications

• No publications reported this period

Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: A graduate student had been hired. We have small team providing input into the design of the research. Cheese class types have been selected based on criteria as discussed in the proposal, that is, varying amounts of lactose, galactose, age, moisture level and variation, and process vs. natural formulations. Moisture experiments have been started. Techniques of moisture analysis, within allowance of the method, are being investigated such as a variety of pre-drying methods, freeze drying, modification of drying method, sample preparation, and splatter determination. PARTICIPANTS: PI: Franco X. Milani, Ph.D., provided the proposal and general concepts of the project. He is the key initial reviewer of scientific and applied content of the work. He will also be for coordination of the dissemination of the information. Graduate Student: Louisa J. Hays, primary researcher, is conducting the laboratory experiments, data analysis, and thesis. Research Associate (Post-doctoral researcher): Cui_e Guang, is providing technical and advisory assistance. Undergraduate Laboratory Assistant: Jan B. Murray, is conducting experimentation under direction of the PI and is providing support services relative to the project. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Preliminary results show there are errors in the moisture determination that correlate to factors presented in the hypothesis of the proposal, that is, there are factors related to the preparation of the sample, microbiological and chemical induced composition changes, formulation selections, sequence of analysis, and method of analysis. Current work is now focused on replication and the developing statistical and mechanistic model of operation. Outcome and impact of the work to date is too preliminary to draw general conclusions at this time.

Publications

• No publications reported this period