PREDICTING THE PHYSICOCHEMICAL PROPERTIES OF PORK BELLY AND THE EFFECT OF COOKING AND STORAGE CONDITIONS ON BACON SENSORY AND CHEMICAL CHARACTERISTICS A Thesis Submitted to the College of Graduate and Postdoctoral Studies in Partial Fulfilment of the Requirements for the Degree of Doctor of Philosophy in the Department of Food and Bioproduct Sciences University of Saskatchewan Saskatoon By Olugbenga Philip Soladoye 2017 © Copyright Olugbenga Philip Soladoye, July 2017. All rights reserved. PERMISSION TO USE In presenting this thesis, in partial fulfillment of the requirements for a degree of Doctor of Philosophy from the University of Saskatchewan, I agree that the Libraries of this University may make it freely available for inspection. I further agree that permission for copying of this thesis in any manner, in whole or in part, for scholarly purposes may be granted by the professor or professors who supervised my thesis work or, in their absence, by the Head of the Department or the Dean of the College in which my thesis work was done. It is understood that any copying or publication or use of this thesis, or parts thereof, for financial gain shall not be allowed without my written permission. It is also understood that due recognition shall be given to me and to the University of Saskatchewan in any scholarly use which may be made of any material in my thesis. Requests for permission to copy or to make other use of material in this thesis in whole or in part should be addressed to: Head of the Department of Food and Bioproduct Sciences University of Saskatchewan Saskatoon, Saskatchewan Canada S7N 5A8 i ABSTRACT The first objective of this research was to use a widely varying pig population to create prediction algorithms for dual energy X-ray absorptiometry (DXA) pork carcass compositional estimate and pork belly softness measurement. Further, bellies with compositional extremes were used in bacon production and cooked in two ways to determine the impact of composition, storage days and cooking method on lipid and protein oxidation as well as heterocyclic aromatic amines. A total of 648 pigs, either barrows or gilts, from three sire breeds (Lacombe, Duroc or Iberian boar × Large White * Landrace F1 dams), were provided one of three diets (conventional, canola-based or flaxseed-based feed) ad libitum until they reached either ~120 or 140 kg slaughter weight. These variations were intentionally introduced so that the animal population could adequately represent the variation applicable to commercial production. Following slaughter, carcass sides and primal cuts were scanned under DXA equipment. For the second experiment, 198 left side bellies were assigned to belly-flop angle and subjective score measurements to evaluate pork belly softness. The third experiment employed 44 right side bellies which were randomly selected from the treatment extremes (barrows or gilts, Iberian or Lacombe, and control or flaxseed based diet). These 44 bellies were processed into bacon slices which were cooked with either microwave heating or pan frying after 2 or 28 days of refrigerated storage. Regardless of variation in animal population, DXA accurately predicted dissected/chemical fat and lean content of carcass sides and primal cuts (R2 > 0.94, P < 0.01; RSD, 0.8 to 2.9%). The multifactorial nature of pork belly softness was confirmed with a stepwise regression model that explained up to 77 and 83% of subjective belly softness score and belly-flop angle measurement, respectively, with both chemical and dimensional factors as the predictors. Employing belly-flop angle measurement in the assessment of pork belly softness would require a correction for belly length. Although microwave cooking of bacon led to a significantly higher increase in protein oxidation (P < 0.001), cooking in a frying pan resulted in higher increase in heterocyclic aromatic amines and lipid oxidation in bacon (P < 0.001). Storage days and belly composition did not affect the production of these chemical compounds (P > 0.05). The cooking treatments and storage days also had minimal effects on bacon sensory attributes. Overall, the present study established mathematical models to improve DXA estimate of pork carcasses and enhance pork belly softness assessments. The results could also inform public health recommendations regarding choice of cooking method for bacon. ii ACKNOWLEDGEMENTS Now the words of Eleanor Roosevelt resonate more with me, that “the future belongs to those who believe in the beauty of their dreams”. Although I couldn’t see the whole staircase, I took the first step anyways, relishing the support of great mentors and friends that nature has blessed me with. First, I would like to whole-heartedly express my appreciation to my incredible supervisors; Drs. Manuel Juarez and Phyllis Shand for their unparalleled support, understanding, patience, guidance and advice during the entire period of my doctoral studies. You believed in what I can be, you gave me a chance and never doubted my ability for once! You are an integral part of this success story and your names are written with gold on the table of my heart. I would also like to express my profound gratitude to Dr. Jennifer Aalhus whose motherly predisposition was a great encouragement to me. Your great advice, support, kindness and grace have helped me this far. More than a million thanks. The unparalleled encouragement and advice of my advisory committee; Drs. Nicholas Low, Robert Tyler, Michael Nickerson and Denise Beaulieu will never be forgotten and I will forever be grateful for all your kind support. The immense contribution of my external examiner; Dr. Jason Apple is also greatly acknowledged. The generous funding and support from the Canadian Beef Grading Agency, Alberta Livestock and Meat Agency Ltd. (ALMA), University of Saskatchewan Devolved Scholarship and the Natural Sciences and Engineering Research Council of Canada (NSERC) have made this dream a reality. I am eternally grateful for your support. You have not only made a man, you have made a generation! I would also want to acknowledge all the technical staff of Lacombe Research and Development Centre for their great help in the course of my research. You all hold a special place in my heart. I will never forget the incredible support of my family and friends who stood by me through the thick and thin of this program. My parents, Mr and Mrs Nathaniel and Grace Soladoye, all my siblings and my friends; Ayodele Olagunju, Jeremy Sealock, Duncan Henry, Rhona Thacker, Dapo Fawehinmi, Ayoola Jinadu, Emmanuel Leonard, Peter Maduakor, Ola Amusa, Seun Oluwajana and Omotola Olaniyan, to name a few. All your smiles and tolerances were healing balm for me especially when I felt broken and alone. Thank you so much. “Now unto HIM who is able to do exceeding abundantly above all that we may think or ask of HIM according to the power that dwell him us.” To this only true God, my allegiance I forever pledge! iii DEDICATION To all those who dare to dream despite their dreads iv TABLE OF CONTENTS PERMISSION TO USE ................................................................................................................... i ABSTRACT .................................................................................................................................... ii ACKNOWLEDGEMENTS ........................................................................................................... iii DEDICATION ............................................................................................................................... iv TABLE OF CONTENTS ................................................................................................................ v LIST OF TABLES .......................................................................................................................... x LIST OF FIGURES ...................................................................................................................... xii LIST OF ABBREVIATIONS ...................................................................................................... xiii 1 INTRODUCTION..................................................................................................................... 1 1.1 Objectives ................................................................................................................. 3 1.2 Hypotheses ............................................................................................................... 3 2 LITERATURE REVIEW ........................................................................................................ 5 2.1 Bacon and its recent consumption trend ................................................................... 5 2.1.1 History of bacon ....................................................................................................... 5 2.1.2 Recent consumption trends ...................................................................................... 6 2.2 Bacon processing .................................................................................................... 11 2.2.1 Raw material selection and sorting ........................................................................ 11 2.2.2 Curing methods ...................................................................................................... 12 2.2.2.1 Pump curing ........................................................................................................ 12 2.2.2.2 Dry curing ..........................................................................................................