1 Optimization of a Pretreatment to Reduce Oil Absorption in Fully
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1 Optimization of a Pretreatment to Reduce Oil Absorption in Fully Fried, Battered and Breaded Chicken Using Whey Protein Isolate as a Postbreading Dip A thesis presented to the faculty of the College of Health and Human Services of Ohio University In partial fulfillment of the requirements for the degree Master of Science Eunice Mah June 2008 2 This thesis titled Optimization of a Pretreatment to Reduce Oil Absorption in Fully Fried, Battered, and Breaded Chickens Using Whey Protein Isolate as a Postbreading Dip by EUNICE MAH has been approved for the School of Human and Consumer Sciences and the College of Health and Human Services by Robert G. Brannan Assistant Professor of Human and Consumer Sciences Gary S. Neiman Dean, College of Health and Human Services 3 ABSTRACT MAH, EUNICE, M.S., June 2008, Food and Nutrition Optimization of a Pretreatment to Reduce Oil Absorption in Fully-Fried, Battered, and Breaded Chicken Using Whey Protein Isolate as a Postbreading Dip (193 pp.) Director of Thesis: Robert G. Brannan As consumers become more aware of the deleterious effects of a high-fat diet, there are increased efforts to lower fat content in foods. The effectiveness of whey protein isolate (WPI) solution as a postbreading dip to reduce oil absorption in deep-fried, battered, and breaded chicken patties and its effect on sensory properties was investigated. Chicken patties were battered, breaded with either crackermeal or Japanese breadcrumbs, and dipped in WPI solutions prepared at four different protein concentrations (0%, 2.5%, 5%, and 10% w/w WPI) that were adjusted to pH 2, 3, and 8 before being deep-fried. Undipped chicken patties served as the control. Overall, the most effective treatment was observed for WPI solutions made at high concentrations (5% and 10% WPI) at low pH levels (pH 2 and 3). The highest lipid reduction was 31.2% for patties breaded with crackermeal (CMP) at pH 2 with 5% WPI and 37.5% for patties breaded with Japanese breadcrumbs (JBP) at pH 2 with 10% WPI. The only perceivable sensory changes in treated patties were related to color, hardness, and crunchiness. Increasing WPI concentration caused darkening of JBP but made CMP lighter while patties treated at pH 8 were significantly darker across all WPI concentrations. The presence of WPI increased perceived hardness and crunchiness for CMP but only increased perceived hardness for JBP. Variations in pH levels did not affect texture for both breading systems. JBP that showed the highest lipid reduction (10% WPI at pH 2) 4 were observed to be darker, less yellow, but did not produce any perceivable changes in hardness or crunchiness, while CMP with the lowest lipid content (5% WPI at pH 2) were darker, more yellow, harder, and crunchier. These results suggest that WPI exhibits oil- barrier properties that do not significantly affect the flavor of the product, irregardless of breading type, thus making it a promising alternative in lowering fat content of fried foods. Approved: _____________________________________________________________ Robert G. Brannan Assistant Professor of Human and Consumer Sciences 5 ACKNOWLEDGMENTS I would like to acknowledge the following amazing individuals who have supported me directly and indirectly throughout my M. S. studies and in the production of this thesis. Thank you so much for making me the person that I am. Dr. Robert G. Brannan Joshua Bear Dr. Darlene Berryman Joshua O’Donnel Dr. Elizabeth Crockett Julian Price Dr. Ann Paulins Katie Horn Amanda Palmer Keely Trisel (Ashley) Beamish Ken McLean Ashley Zurmehly Lisa Dael Beth Wiseman Dr. Margaret Manoogian Bobbi Conliffe Rachel Bisset Chris Sandford Sarah Diamond Crystal Hazen Simona Allen Daria Janssen Svetha Swaminathan David Holben Dr. Sky Cone Dr. Deb Murray Vishakha Magon Ms. Diana Manchester Doug Grammer All my other friends, classmates, and Dr. Fang Meng professors at Ohio University Gary Saum Gerard Akindes (and gang) The funding agency: Dr. Grace Brannan National Dairy Council Discovery Pilot Program Grant Harris Dr. Greg Janson Jane Boney And last but not least, Jessica Grey My mum, dad, brother, and sister who are Jody Grenert always there for me. 6 TABLE OF CONTENTS Page Abstract ................................................................................................................................3 Acknowledgments................................................................................................................5 List of Tables .....................................................................................................................11 List of Figures ....................................................................................................................13 Chapter 1: Introduction ......................................................................................................14 Statement of the Problem ...................................................................................... 16 Research Questions ............................................................................................... 17 Significance of Study ............................................................................................ 17 Delimitations and Limitations............................................................................... 18 Definition of Terms............................................................................................... 20 List of Abbreviations and Acronyms .................................................................... 21 Chapter 2: Review of the Literature ...................................................................................22 Introduction ........................................................................................................... 22 Consumption of Fried Foods and Fat Intake............................................. 22 Battered and Breaded Foods ..................................................................... 24 Theories of Oil Uptake in Fried Items .................................................................. 26 Stages of Deep-Fat Frying ........................................................................ 26 Mechanisms of Oil Absorption ................................................................. 27 Water Replacement ....................................................................... 27 Cooling-Phase Effect .................................................................... 27 Surfactant Theory of Oil Absorption ............................................ 31 7 Factors Affecting Oil Absorption ......................................................................... 32 External Factors Affecting Oil Absorption ............................................... 33 Composition of the Frying Oil ...................................................... 33 Frying Time and Temperature ...................................................... 33 Postfry Handling ........................................................................... 34 Intrinsic Factors Affecting Oil Absorption ............................................... 34 Methods for Reduction of Oil Absorption ............................................................ 35 Nonprotein-Based Coatings or Films........................................................ 37 Protein-Based Coatings or Films .............................................................. 42 Protein Gelation ............................................................................ 45 Factors affecting protein gelation ..................................... 45 Whey Protein ................................................................................ 48 Gelation of Whey Protein ............................................................. 49 Effect of pH on whey protein gelation and oil uptake. ..... 51 Effect of concentration on whey protein gelation and oil uptake.. .............................................................................. 53 Sensory Evaluation of Foods ................................................................................ 55 Conclusion ............................................................................................................ 57 Chapter 3: Methodology ....................................................................................................60 Overview of Approach .......................................................................................... 60 Data Collection and Analysis................................................................................ 64 Materials ................................................................................................... 64 Preparation of Deep Fried Samples .......................................................... 64 8 Objective Analysis ........................................................................ 65 Oil degradation.................................................................. 65 Lipid analysis. ................................................................... 65 Moisture analysis. ............................................................. 66 Texture and color analysis. ............................................... 66 Sensory Analysis ........................................................................... 68 Panelist selection and training. ......................................... 68 Evaluation of samples. ...................................................... 70 Statistical Analysis .......................................................................