AN ABSTRACT OF THE THESIS OF Siripom Pipatsattayanuwong for the degree of Doctor of Philosophy in Food Science and Technology presented on May 6. 1998. Title: Instrumental and Sensory Texture Profile Analysis of Asian Wheat Noodles. Abstract approved: ___^ , , ^ Mina R. McDaniel Texture, a critical property of Asian wheat noodles, is normally assessed by sensory evaluation. However, sensory evaluation may be impractical for wheat breeders and noodle researchers who need to evaluate a large number of samples and have limited sample. Instrumental Texture Profile Analysis (TPA) has been widely employed to evaluate Asian wheat noodle texture. Nevertheless, a standardized method for performing TPA on these products has not been established. A series of studies were conducted to develop a testing method to best relate TPA results to sensory texture characteristics of Asian wheat noodles. First, the optimum TPA testing conditions (crosshead speed and degree of deformation) were determined for each noodle category (alkaline, instant fried, salted flat, and salted round), and were defined as the conditions which best related their results to the sensory data. Partial Least Squares (PLS2) was used to examine relationships between sensory first-chew characteristics (hardness, cohesiveness, springiness, denseness, starch between teeth, and toothpull) and TPA output (peak areas and heights). Response Surface Methodology determined the optimum TPA conditions (crosshead speed and % deformation) as follow: 1 mm/s and 85 % for alkaline, 1 mm/s and 70% for instant fried and salted round, and 5 mm/s and 65 % for salted flat noodles. Second, the effects of two sample cooking factors: noodle weights (20, 50, 100 g) and noodle to water ratios (1:10, 1:20) and three holding factors: media (with, without water), temperatures (25, 55 0C), and times (2, 15, 30 min), on the TPA results were investigated. Cooking factors did not significantly affect the TPA results but higher holding temperatures, the use of water as a holding media, and longer holding time significantly decreased most TPA parameters' values. Third, relationships between TPA and sensory first-chew parameters were examined for each noodle category. Predictive models of each sensory first-chew attribute were developed using linear and nonlinear (Fechner and Stevens) models, with single and multiple parameters. Hardness could be satisfactorily predicted by a single TPA parameter (area 1 or area 2), but other attributes required multiple parameters in the models to be satisfactorily predicted. Different model types were selected for each sensory attribute and noodle category. TPA peak area 1 and 2 were the best predictors for first-chew characteristics of cooked Asian wheat noodles. ©Copyright by Siripom Pipatsattayanuwong May 6, 1998 All Rights Reserved Instrumental and Sensory Texture Profile Analysis of Asian Wheat Noodles by Siripom Pipatsattayanuwong A THESIS Submitted to Oregon State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Presented May 6, 1998 Commencement June 1998 Doctor of Philosophy thesis of Siripom Pipatsattayanuwong presented on May 6, 1998 APPROVED: -1 j - -.i-^s (. « 1 Major Professor, representing Food Science and Technology Chaiprif Department c(f Food Science and/Technology Dean of Graduatee^hool I understand that my thesis will become part of the permanent collection of Oregon State University libraries. My signature below authorizes release of my thesis to any reader upon request. Siripor4jPipatsattayanuwong,<^!uthor ACKNOWLEDGEMENT I would like to express my sincere gratitude to my major professor. Dr. Mina R. McDaniel, for her guidance, care, and support. She has been my mentor and inspiration for everything I have accomplished throughout my stay at the sensory lab. Her incredible personality and love will always be remembered by me. I will be ever thankful of knowing her and having her as my advisor. I would also like to thank my committee members for all their devotion to my program and for helping me with my thesis. They have made all my program meetings fun, informative, and valuable experience. Special thanks to Dr. David Lundahl for helping me with the data analysis. Thanks also to Dr. Cliff Pereira for his input on statistical issues. Finally, thanks to Dr. Skip Rocheford and Dr. Russell Ingham for their input and comments on many aspects of my thesis. I would like to thank all friends at the sensory lab, Anne, Naomi, Lotika, Vivek, Sheri, Andrea, Sylvia, Judy, Rita, Laurie, Cindy, Jeff, Anna, and Shuo, for making the sensory lab my home. Special thanks to Sirinmas (Onn) for being my great friend and for being someone I could always count on, all these past years in Corvallis. Thanks to Mei-Fei for all the joy and laughter she brought. I would like to especially thank Dr. Sonia Rubico-Jamir who has been my teacher and my dear friend, and thank her for her encouragement, understanding, and friendship. Thanks to two of my special friends at the sensory lab, Mimi and Rohan, for their memorable friendship, help, care, and love. Their company will always remain in my mind as a truly joyful, fun, and heart-warming memory. I thank all my noodle descriptive analysis panelists, Rohan, Lotika, Kathleen, Jana, Laurie, Rebecca, Susan, Nancy, Maya, Chris, Rita, and Mona for their patience and devotion towards learning about the sensory properties of Asian wheat noodles and making the noodle panel a quality panel. Appreciation is also extended to my thesis editorial board, Rohan, Lotika, Anne, and Naomi for correcting the grammatical mistakes in my thesis. I would like to express my gratitude to Dr. ZoeAnn Holmes for her generosity in letting me use the texture analyzer TA.XT2 for all of my studies. These studies would definitely not have been possible without her help. I would also like to extend my sincere gratitude to the staff at the Wheat Marketing Center, Portland, for all their help and information about wheat and Asian noodles. I would like to dedicate this thesis to my parents who have given me everything in my life. Great thanks to them for their enormous love, support, and encouragement. They are the main reason that made me come this far. Thanks also to all my other family members for their love and support. A deep appreciation is extended to Becky Tseng for her unconditional love and unforgettable friendship, and to Chee-Keong Chua for his care, understanding, and support. CONTRIBUTION OF AUTHORS Dr. David S. Lundahl was involved in the design and analysis of the manuscript. TABLE OF CONTENT Page I. THESIS INTRODUCTION 1 II. LITERATURE REVIEW 5 Asian Noodles 5 White Salted Noodles 6 Yellow Alkaline Noodles 7 Instant Fried noodles 9 Descriptive Analysis 10 Flavor Profile Method 11 Texture Profile Method 12 Quantitative Descriptive Analysis. 13 Spectrum™ Method 15 Free-Choice Profile Method 16 Subjective Measurements of Noodle Texture 16 Instrumental Measurement of Noodle Texture 18 Texture Profile Analysis (TPA) 20 Response Surface Methodology (RSM) 24 Partial Least Squares Regression (PLS) 26 III. PROTOCOL DEVELOPMENT FOR INSTRUMENTAL TEXTURE PROFILE ANALYSIS OF ASIAN WHEAT NOODLE 29 Abstract ^ 30 Introduction 31 Materials and Methods 34 Samples and Sample Preparation 34 Sensory Evaluation 37 TABLE OF CONTENT (Continued) Page Instrumental Test 39 Experimental Design 42 Statistical Analysis 43 The Estimator for the Relationship of Instrumental to Sensory Data 43 The Estimator for Repeatability of the TPA test 46 The Estimator for Sensitivity of the TPA test 47 Response Surface Regression Analysis 48 Results and Discussion 49 Alkaline Noodles 49 Instant Fried Noodles 56 Salted Flat Noodles 64 Salted Round Noodles 71 Conclusion 77 References 79 IV. EFFECTS OF SAMPLE COOKING AND HOLDING METHODS ON TEXTURE PROFILE ANALYSIS TEST RESULTS AND PERFORMANCE OF COOKED WHITE SALTED NOODLES 83 Abstract 84 Introduction 85 Materials and Methods 87 Samples 87 Sample Cooking Methods 87 Sample Holding Methods 88 TPA Test 89 Experimental Design 90 Statistical Analysis 90 Repeatability Calculation 92 Reproducibility Calculation 93 TABLE OF CONTENT (Continued) Page Results and Discussion 94 Effects of Batch Weight 94 Effects of Noodle:Water Ratio 99 Effects of Holding Condition. 102 Effects of Holding Time. 103 Repeatability ofTPATest 108 Reproducibility of TPA Test 112 Conclusion 115 References 115 V. MODEL DEVELOPMENT FOR PREDICTING SENSORY FIRST-CHEW CHARACTERISTICS OF COOKED ASIAN WHEAT NOODLES 119 Abstract 120 Introduction 121 Materials and Methods 125 Samples 125 Sample Preparation 125 Sensory Evaluation 128 Instrumental Measurements 130 Statistical Analysis 132 Results and Discussion 133 Correlations 133 Within Sensory Parameters 133 Between Sensory and Instrumental Parameters 135 Predictive Models 140 TABLE OF CONTENT (Continued) Page Hardness 140 Cohesiveness 143 Springiness 145 Denseness 148 Starch Between Teeth 150 ToothpulL 150 Conclusion 153 References 154 VI. Thesis Summary 158 Bibliography 161 LIST OF FIGURES Figure Page III. 1. Probe (A) and base (B) used for performing Texture Profile Analysis of cooked Asian wheat noodles 41 III. 2. Force-time curve output produced by instrumental TPA 43 III. 3. Alkaline noodles: Contour plot of % variation in sensory data explained by instrumental data obtained by various combinations of crosshead speed and degree of deformation 52 III. 4. Alkaline noodles: Contour plot of sensitivity (x samples,) of (a) peak area 1, (b) peak area 2, (c) peak area 3, (d) peak height 1, and