Changes in Protein-Water Dynamics Impact the Quality of Chicken Meat Post Freezing DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By John Charles Frelka, M.S. Graduate Program in Food Science and Technology The Ohio State University 2017 Dissertation Committee: Dr. Dennis R. Heldman, Advisor Dr. Farnaz Maleky Dr. Sudhir K. Sastry Dr. Yael Vodovotz Dr. Macdonald P. Wick Copyrighted by John Charles Frelka 2017 Abstract Freezing is one of the most common food preservation methods in the modern world. This method relies on the phase change of liquid water to solid ice, thus reducing the mobility of the system and, in combination with lowered temperature, reducing chemical and biological reactions detrimental to food quality. However, the formation of ice crystals can disrupt the structure of the food matrix, causing loss of quality. Protein-based foods, such as meat, are unique physical systems that have different challenges than fruit and vegetable products. The overall objective of this research was to better understand and measure the physical changes in protein-water interactions in chicken during the freezing process and during frozen storage. The specific objectives aimed to understand the effects of freeze time, storage temperature, and freeze/thaw abuse. The effect of characteristic freeze time (CFT) on the physical quality of chicken meat proteins was explored using typical quality measurements and thermal analyses. CFT ranged from 2.4 to 104 min compared to an unfrozen control. Total moisture, protein extraction, brine uptake, myofibrillar fragmentation index, enthalpy, and gelation were measured after samples were thawed. The total enthalpy as well as relative contributions of each peak were significantly higher after freezing, regardless of CFT. The gelation of salt soluble proteins varied with CFT and the gels had significantly different G’ between ii the fast and medium freezing CFT. There was a 40% decrease in the final G’ between the unfrozen and slow frozen samples. The effect of frozen storage temperature was explored in an aqueous extract model system and in whole meat systems. The model system was used to study myoglobin oxidation. This study found that under frozen conditions there was a rate acceleration with a maximum around −20°C. This effect was magnified by the addition of NaCl to the system. Whole meat products were tested to determine if this effect was evident in these systems. Quality was measured in whole chicken breasts and ground chicken patties over 3 months of storage. Temperature did not significantly impact any attribute measured. Two freezing rates were tested in patties but did not result in different rates of quality loss. The reverse stability evident in the model system was not observed in the chicken products. The impact of freeze/thaw abuse on the quality of chicken was assessed using magnetic resonance imaging. Drip loss was the only measured attribute that showed significant change with increased freeze/thaw cycles. Physical distribution of water within the chicken breasts was observed in unbrined samples as freeze/thaw cycles increased. There were significant shifts in the proton density distributions from MRI images. Differences were not as pronounced in brined samples, suggesting a level of cryoprotection conferred by the brine. In both brined and unbrined samples, only small differences in T2 distributions were observed. Using NMR micro-imaging significant shifts in T2 distributions were observed in unbrined samples. Water plays a critical role in iii the structure and quality of chicken meat. This research adds to the understanding of how freezing impacts these critical protein-water interactions. iv Acknowledgments I greatly appreciate the guidance of Dr. Dennis R. Heldman through the process of the completion of this degree. His experience has been an invaluable resource and I am grateful for the opportunity to learn from him. Thank you to my committee members, Drs. Maleky, Sastry, Vodovotz, and Wick. Special thanks to Dr. Wick for teaching me how to think like a meat scientist and providing guidance through this field I knew nothing about. Special thanks also to Dr. Vodovotz for teaching me the ways of physical properties and how to find the proper instrument to solve any problem. Thanks to the Ohio Agricultural Research and Development Center SEEDS program for funding part of this research. Thanks also to the Dale A. Sieberling research endowment for providing the laboratory funds that made much of this research possible. This project would not have been possible without the efforts of my labmates, particularly Mr. David Phinney, who provided as much guidance as friendship, and Ms. Sravanti Paluri, my lab bro from beginning to end and helping write my codes. Thanks to all though who assisted in the data acquisition, in particular Jace Metzcar. Thanks also to those at The Ohio State University’s Meat Laboratory, particularly Mr. Tom Katen and Mr. Ron Cramer for their help and accommodation. Thanks to Dr. Huyen Nguyen for her help running the MRI scans and Dr. Xiangyu Yang for his help in the analysis of the MRI v data. Thanks to the staff at the Campus Chemical Instrumentation Center NMR facilities, particularly Drs. Chunhua Yuan and Tanya Whitmer. Those companies who provided materials are greatly appreciated including Gerber’s Poultry and West Liberty Foods. vi Vita 2007................................................................San Joaquin Memorial High School 2011................................................................B.S. Food Science and Technology, University of California, Davis 2013................................................................M.S. Food Science and Technology, University of California, Davis 2013 to present ..............................................Graduate Research Associate, Department of Food Science and Technology, The Ohio State University Publications Phinney, D.M., J.C. Frelka, D.R. Heldman. 2016. Chemical-free neutralization of caustic peeled tomato slurry to reclaim wastes. Food Bioprod. Process. 100:545-550 Phinney, D.M., J.C. Frelka, J.L. Cooperstone, S.J. Schwartz, D.R. Heldman. 2017. Effect of solvent addition sequence on lycopene extraction efficiency from membrane neutralized caustic peeled tomato waste. Food Chem. 215:354-361 Phinney, D.M., J.C. Frelka, D.R. Heldman. 2017. Composition based prediction of temperature dependent thermophysical food properties: Reevaluating component groups and prediction models. J. Food Sci. 82:6-15. Fields of Study Major Field: Food Science and Technology vii Table of Contents Abstract ............................................................................................................................... ii Acknowledgments............................................................................................................... v Vita .................................................................................................................................... vii Publications ....................................................................................................................... vii Fields of Study .................................................................................................................. vii Table of Contents ............................................................................................................. viii List of Tables ................................................................................................................... xiv List of Figures ................................................................................................................... xv CHAPTER 1: Introduction ................................................................................................. 1 1.1 Objectives ........................................................................................................... 3 CHAPTER 2: Literature Review ........................................................................................ 4 2.1 Meat – Definition and Structure ......................................................................... 4 2.2 Meat Quality ....................................................................................................... 7 2.2.1 Fresh Meat Products ..................................................................................... 7 2.2.2 Processed Meat Products ............................................................................ 13 viii 2.3 Measurement of Meat Quality .......................................................................... 15 2.3.1 Typical Methods ......................................................................................... 16 2.3.2 Advanced Methods ..................................................................................... 21 2.4 Influence of Freezing on Meat Quality ............................................................. 31 2.4.1 Mechanisms of Water Holding in Meat ...................................................... 31 2.4.2 Freezing Rate .............................................................................................. 33 2.4.3 Frozen Storage Temperature ....................................................................... 36 2.5 Conclusion ........................................................................................................ 40 2.6 REFERENCES ................................................................................................