Proquest Dissertations
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Each original is also photographed in one exposure and is included in reduced form at the back of the book. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6” x 9” black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. UMI A Bell & Howell Infonnation Company 300 North Zed) Road, Ann Arbor MI 48106-1346 USA 313/761-4700 800/521-0600 CAROTENE THERMAL DEGRADATION PRODUCTS AND THEIR EFFECTS ON THE OXIDATIVE STABILITY OF SOYBEAN OIL DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Donald Frank Steenson, M.S. ***** The Ohio State University 1999 Dissertation Committee: Approved by Professor David B. Min, Advisor Professor Steven J. Schwartz Advisor Professor Grady W. Chism III Food Science and Nutrition Professor Sheryl A. Barringer Graduate Program ÜMI Number: 9931679 UMI Microform 9931679 Copyright 1999, by UMI Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, MI 48103 ABSTRACT Soybean oil used in processed foods is susceptible to lipid oxidation. Carotenes are utilized as colorants in processed foods containing soybean oil. Though carotenes are easily degraded during thermal processing, little is known regarding the effects of thermally degraded carotenes on the oxidative stability of soybean oil. Thermally degraded (3-carotene or lycopene solutions were added to soybean oil samples at concentrations of 0, 25,45, and 50 ppm, respectively. Each sample, as well as controls containing 5, 25, and 50 ppm o f unheated (3-carotene or lycopene, contained 3 ppm of chlorophyll to allow photosensitized singlet oxygen oxidation to occur. The vial containing each sample was sealed airtight and stored either at 25°C in a light box (1650 lumens) or in a dark oven at 60°C. The oxidative stability of each soybean oil sample was determined by measuring (every 4 hours for 24 hours) peroxide value and headspace oxygen depletion by thermal conductivity gas chromatography. Oxidative stability was further identified by first utilizing solid phase microextraction (SPME) fibers to adsorb volatile oxidation products in the headspace of the samples, then quantifying and comparing the volatiles’ total peak area from their respective gas chromatogram. Soybean oil samples containing 50 ppm degraded (3-carotene displayed 11.5% higher peroxide values (under light) as well as higher headspace oxygen depletion values (in the dark) when compared with controls (p<0.01). Lycopene degradation products (50 ppm) in soybean oil decreased peroxide values up to 10.5% under light, and significantly decreased headspace oxygen depletion of samples in the dark (p<0.05). Over all concentration ranges, headspace oxygen depletion values for samples stored under light containing either P-carotene or lycopene degradation products did not differ significantly from controls. After 30 days of storage in the dark at 60°C, samples containing 50 ppm degraded p-carotene displayed a significantly higher (p<0.05) SPME-GC total volatile peak area when compared with controls containing 50 ppm düLl-trans P-carotene. Under similar conditions, samples containing 50 ppm degraded lycopene displayed a significantly lower (p<0.05) SPME-GC total volatile peak area when compared with controls containing only oil. These results indicate that thermally degraded P-carotene can act as a prooxidant in soybean oil exposed to elevated temperatures, which may cause a decrease in the oxidative stability of thermally processed foods containing soybean oil. Thermally degraded lycopene, however, may act as an antioxidant in soybean oil exposed to elevated temperatures and therefore may actually increase the oxidative stability o f food systems containing soybean oil. Ill Dedicated to my wife and family. IV ACKNOWLEDGMENTS I would like to thank my advisor. Dr. David B. Min, for his unequaled enthusiasm and dedication in helping me to achieve at the highest level possible in all my scholastic and research endeavors. To my dissertation committee. Dr. Grady W. Chism, Dr. Steven J. Schwartz, and Dr. Sheryl A. Barringer: I would like to extend my sincere appreciation for the constructive criticism, comments, and suggestions afforded to me throughout my degree program. A special thanks goes out to Cathy Zirkle, A1 McRoberts, Carol Rogers, Ed Zirkle, and Linda Burianek, members of the department support staff who provided a wide range of invaluable assistance and truly helped get ‘the necessary things’ done. I deeply appreciate the assistance with the GC-MS analyses that I received from Susan Hatcher. I am of course grateful to all my friends and fellow colleagues in the department for their never-ending support and encouragement throughout the day-to-day nuances o f graduate school life, especially Sherri, Monica, Cindy, Kwok-Man, Steve, Sarit, Joe, Julie, Minhthy, Mario, Keith, and Sinan. VITA August 15,1970 Bom — Louisville, Kentucky 1992 B.S. Biology Bucknell University Lewisburg, PA 1994 M.S. Foods and Nutrition The Florida State University Tallahassee, FL 1994 - 1995 ............................................................ Quality Control Chemist Mulberry Ethanol, L.P. Mulberry, FL 1995 - 1996 Laboratory Scientist P. E. LaMoreaux & Associates Lakeland, FL 1996 - 1997 .............................................................Graduate Research Assistant Dept, of Food Science and Technology The Ohio State University Columbus, OH 1997-1999 USD A Fellow Dept, of Food Science and Technology The Ohio State University Columbus, OH VI PUBLICATIONS 1. Steenson, D. F., and Sathe, S. K. 1995. Characterization and digestibility of Basmati rice {Oryza sativa L. var. Dehraduni) storage proteins. Cereal Chemistry. 72 (3): 275- 280 2. Min, D. B., and Steenson, D. F. Crude fat analysis. In Food Analysis, 2"^* edition, Nielsen, S. S., ed. Gaithersburg: Aspen Publishers, Inc., 1998, pp. 201-215. FIELDS OF STUDY Major Field: Food Science and Technology V ll TABLE OF CONTENTS Page Abstract....................................................................................................................................... ii Dedication..................................................................................................................................iv Acknowledgments ...................................................................................................................... v Vita..............................................................................................................................................vi List o f Tables.......................................................................................................................... xiii List o f Figures .......................................................................................................................... xv Chapter 1 Introduction..............................................................................................................1 Chapter 2 Literature Review.................................................................................................. 5 2.1 Vegetable oils ............................................................................................................. 5 2.1.1 Production and utilization............................................................................ 5 2.1.2 Soybean oil instability ................................................................................. 7 2.1.3 Free radical autoxidation............................................................................. 8 2.1.3.1 Prooxidants in oils ........................................................................... 9 2.1.3.2 Free radical scavengers................................................................ 10 2.1.4 Photosensitized oxidation .......................................................................... 11 2.1.4.1 Type 1 and H processes ................................................................ 12 2.1.4.2 Sensitizers in o ils .......................................................................... 14 2.2 Volatile soybean oil oxidation products ................................................................ 15 2.2.1 Formation of volatile compounds ............................................................. 17 2.2.2 Isolation