Oil absorption during deep-fat frying: mechanisms and important factors Aman-Mohammad Ziaiifar To cite this version: Aman-MohammadZiaiifar. Oilabsorptionduringdeep-fatfrying: mechanismsandimportantfactors. Engineering Sciences [physics]. AgroParisTech, 2008. English. ￿NNT: 2008AGPT0084￿. ￿pastel- 00003693￿ HAL Id: pastel-00003693 https://pastel.archives-ouvertes.fr/pastel-00003693 Submitted on 17 Jun 2009 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. N° /__/__/__/__/__/__/__/__/__/__/ THÈSE pour obtenir le grade de Docteur de l’Institut des Sciences et Industries du Vivant et de l’Environnement (Agro Paris Tech) Spécialité : Génie des Procédés Alimentaires présentée et soutenue publiquement par Aman Mohammad ZIAIIFAR le 9 décembre 2008 OIL ABSORPTION DURING DEEP-FAT FRYING: MECHANISMS AND IMPORTANT FACTORS Travail réalisé : AgroParistech, UMR GénIAl 1145, 1 avenue des Olympiades, F-91744 MASSY Devant le jury : M. Alain LEBAIL, Pr, ENITIAA …………………………………… Président M. Alain KONDJOYAN, Dr, INRA ………………………………... Rapporteur M. Antoine COLIGNAN, Pr, CIRAD ……………………………... Rapporteur M. Pedro BOUCHON, Dr, Univ. Catholique du Chili …………. Examinateur M. Gilles TRYSTRAM, Pr, AgroParisTech ………….…………. Examinateur M. Francis COURTOIS, Dr, AgroParisTech …………………… Examinateur i To my wife Ailar and my children Dayan and Ilay ii Acknowledgements I wish to thank AgroParisTech for giving me the opportunity to conduct the PhD work on Food Process Engineering. I wish to thank the food process engineering (GIA-SPAB) department for taking care of me and supporting me for the duration of my project. I would like to start by thanking my major professor, Dr. Francis Courtois, for his guidance throughout my study. He allowed me the freedom to explore new ideas during the pursuit of my doctoral degree yet helped me to stay on the right path when needed. Most importantly I am grateful to Professor Gilles Trystram for his kind welcome to the laboratory. He has also provided unending insight and suggestions which helped to keep the thesis moving to completion. Special gratitude goes to Dr. Bertrand Heyd for his help and useful advice for most of the experimental parts. I appreciate very much for his kindness, his willingness to help and the helpful knowledge I have learned. Many thanks to my thesis defence examiners; Professor Alain LeBail, Professor Antoine Colignan, Dr. Pedro Bouchon and Dr. Alain Kondjoyan for the pain-taking time taken to read this work and for their valuable remarks, observations and advice for improving and enhancing this document. I wish to thank Professor Albert Duquenoy; I enjoyed teaching with him in the practical works of “Appertisation”. I would like to thank the Ministry of Science, Research & Technology of IRAN for the funding to carry out my study and research and SFERE (French company) for the administration helps. Very special thanks to Dr. Ali Bazmi, my dear friend for his support in my academic and non academic steps and special gratitude to my brother, Frahad, for his help in English grammar correction. I wish to thank to administration and technical staff at the department. Special thanks to Monique Belgome and Michèle Bras Dos Santos for their help in administration, Odile Mathieu and Aurélien Neveu for their technical assistance. iii Many thanks to Elisabeth Maltese, my French teacher, for her great advices, guidance, and encouragement from whom I learned the value of communication in a foreign language. The author is very grateful to Donald White for English proof-reading some of the scientific papers. I want to thank my lab mates Richard, Reza, Ladan, Nawel, Alessandro, Abdelghani, Nadia, Emilie, Imen, Teresa, Thibault, Juan, Camille, Hussem, Samir, Souad, Marjorie and Tarif for all the fun, support, friendship, and above all, for making of this a great, living experience. Thank you to all the people close to me and I had a very good time with them, Reza, Bagher, Fateme, Somaye, Ghassem, Zuzana and Behzad. I would like to express my deepest gratitude to my parents, Bairam Mohammad and Saeed Bike, for their endless love and encouragement. They made countless sacrifices to provide me with the best opportunities in my life. Words are incapable to express my appreciation to them. Finally, I wish to express my love and thanks to my wife, who constantly inspired and supported me throughout my study period; at the same time, she has studied her PhD thesis. iv Publications & Communications Publications 1. ZIAIIFAR A.M., ACHIR N., COURTOIS F., TREZZANI I. et TRYSTRAM G. 2008. Review of mechanisms, conditions, and factors involved in the oil uptake phenomenon during the deep-fat frying process. International Journal of Food Science and Technology, 43, 1410-1423. 2. ZIAIIFAR A.M., COURTOIS F., and TRYSTRAM G., 2008. A review of presented modelling of deep-fat frying process (in prep.). 3. ZIAIIFAR A.M., COURTOIS F., and TRYSTRAM G., 2008. Porosity Development and its Effect on Oil Uptake during Frying Process. Journal of Food Process Engineering, doi: 10.1111/j.1745- 4530.2008.00267.x (in press). 4. ZIAIIFAR A.M., COURTOIS F., and TRYSTRAM G., 2008. 2008. Oil absorption during cooling of French fries: experimental study (in prep.). 5. ZIAIIFAR A.M., HEYD B. and COURTOIS F. 2008. Investigation of effective thermal conductivity kinetics of crust/core regions of potato during deep fat frying using modified Lees method. Journal of Food Engineering (submitted paper). Communications 1. ZIAIIFAR A.M., COURTOIS F., and TRYSTRAM G., April 2008. Variation of porosity during frying and cooling of French fries and its relation with oil absorption. Oral presentation & Poster, International Congress of Engineering and Food (ICEF10) Chile. 2. ZIAIIFAR A.M., HEYD B., and COURTOIS F., April 2008. Investigation of heat conductivity variation of crust and core regions of fried potato using modified Lees method, Poster presentation, International Congress of Engineering and Food (ICEF10) Chile. 3. ZIAIIFAR A.M., COURTOIS F., and TRYSTRAM G. September 2008. Investigation of oil physical properties affecting oil absorption during frying process. Oral presentation, 6th Euro Fed Lipid Congress, Greece. v Structure of the thesis Chapter one: Summary of the thesis Chapter Two: Literature reviews Part 1: Review of mechanisms, conditions, and factors involved in the oil uptake phenomenon during the deep-fat frying process Part 2: Modeling of heat and mass transfer during deep-fat frying: a review Chapter three: Results Part 1: Porosity development and its effect on oil uptake during frying process Part 2: Oil absorption during cooling of French fries: experimental study Part 3: Investigation of effective thermal conductivity kinetics of crust and core regions of potato during deep fat frying using modified Lees method vi Table of contents Acknowledgements........................................................................................................................iii Publications & Communications......................................................................................................v Structure of the thesis......................................................................................................................vi Table of contents...........................................................................................................................vii List of figures...............................................................................................................................xiii List of tables..................................................................................................................................xvi Chapter one: Summary of the thesis................................................................................................2 1. Introduction..............................................................................................................................2 2. Hypothesis of the study............................................................................................................2 3. Objectives.................................................................................................................................3 4. Outline of the study..................................................................................................................3 4.1. Introducing the different parts of this thesis......................................................................3 4.2. Porous structure of fried food............................................................................................6 4.2.1. Mechanisms of pore development..............................................................................7 4.2.2. Factors influencing the product porosity....................................................................7 4.2.3. Densities variations during frying process.................................................................8 4.3. Towards modeling of frying process: accessing important properties..............................8 4.3.1. Physical properties.....................................................................................................8 4.3.2. Thermal properties.....................................................................................................9 4.4. Factors affecting final oil content of French fries............................................................10 4.5. Main conclusions.............................................................................................................12 5. Perspectives and recommendation for future work................................................................13 Chapter Two: Literature reviews....................................................................................................17 Part 1: Review of mechanisms, conditions, and factors involved in the oil uptake phenomenon during the deep-fat frying process..............................................................................................18 vii Abstract...................................................................................................................................18 1. Introduction.........................................................................................................................19 2. Nutritional characteristics of frying products.....................................................................20 3. Oil location and period of oil absorption: experimental facts.............................................24 4. Mechanism of oil absorption..............................................................................................27 4.1 Water escape and oil uptake.........................................................................................28 4.2 Capillary pressure and oil uptake.................................................................................29 4.3 Vapour condensation and vacuum effect.....................................................................32 4.4 Adherence and drainage of oil.....................................................................................33 4.5 Conclusion: toward a possible modelling of oil uptake?.............................................34 5. Important factors in oil uptake............................................................................................37 5.1 Product properties affecting oil uptake........................................................................37 5.1.1 Size, shape and surface of product........................................................................37 5.1.2 Composition of product and its density.................................................................39 5.2 Frying Oils properties and oil uptake...........................................................................40 5.2.1 Oil type..................................................................................................................40 5.2.2 Oil aging................................................................................................................41 5.3 Process factors..............................................................................................................42 5.3.1 Preprocessing factors affecting oil uptake............................................................42 5.3.2 Frying factors........................................................................................................46 5.3.3 Post-frying conditions...........................................................................................48 6. Conclusion..........................................................................................................................49 References...............................................................................................................................50 Part 2: Modeling of heat and mass transfer during deep-fat frying: a review............................57 Abstract...................................................................................................................................57 viii 1. Introduction.........................................................................................................................58 2. Classification of frying models...........................................................................................61 2.1. Model types classified by the different zones in product............................................61 2.1.1. Single zone model................................................................................................61 2.1.2. Double zone model...............................................................................................61 2.2. Model types by period of oil absorption.....................................................................62 2.2.1. Single period model for oil absorption.................................................................63 2.2.2. Double period model for oil absorption...............................................................63 2.3. Model types by nature.................................................................................................64 2.3.1. Empirical model...................................................................................................64 2.3.2. Mechanistic model...............................................................................................64 3. Transfer phenomena: heat transfer and mass transfer.........................................................65 3.1. Heat transfer during frying process.............................................................................65 3.1.1. Mechanisms of heat transfer................................................................................66 3.1.2. Modeling of heat transfer.....................................................................................70 3.2. Moisture transfer.........................................................................................................71 3.2.1. Mechanisms of moisture transfer.........................................................................72 3.2.2. Modeling of moisture transfer..............................................................................75 3.3. Oil transfer (uptake)....................................................................................................77 3.3.1. Mechanisms of oil uptakes...................................................................................78 3.3.2. Modelling of oil transfer......................................................................................78 4. Conclusion..........................................................................................................................79 References...............................................................................................................................80 Chapter three: Results....................................................................................................................86 Part1: Porosity development and its effect on oil uptake during frying process........................87 ix