FOOD HYDROCOLLOIDS Food Hydrocolloids 23 (2009) 1–25 Review Food oral processing—A review Jianshe Chen à Procter Department of Food Science, University of Leeds, Leeds LS2 9JT, UK Received 8 June 2007; accepted 17 November 2007 Abstract Food oral processing is an essential procedure not only for the consumption and digestion of foods but also for the appreciation and pleasure of food texture and food flavour. The consumption of a food inside mouth involves various oral operations, including first bite, chewing and mastication, transportation, bolus formation, swallowing, etc. Exact mechanisms and governing principles of these oral operations are still not fully understood, despite of continuous efforts made by scientists from food, psychology, physiology, dental and clinical studies, and other disciplines. This article reviews recent progresses and literature findings about food processing and transformation in mouth, with particular attention on the physiology and rheology aspects of oral operations. The physiological behaviour of human’s oral device is discussed in terms of biting capability, tongue movement, saliva production and incorporation, and swallowing. The complexity of oral processing is analysed in relation to the rheology and mechanical properties of foods. The swallowing and oral clearing process is also examined for its criteria, triggering mechanism, bolus deformation, and the rheology of swallowing. r 2007 Elsevier Ltd. All rights reserved. Keywords: Oral processing; Oral physiology; Food rheology; Food texture; Saliva; First bite; Chewing; Mastication; Bolus; Swallowing Contents 0. Introduction ................................................................................. 2 1. A brief history of food texture studies ............................................................... 2 2. Oral physiology ............................................................................... 4 2.1. Oral cavity .............................................................................. 4 2.2. Teeth and biting .......................................................................... 5 2.3. The tongue .............................................................................. 6 2.4. Saliva.................................................................................. 7 3. Food oral management ......................................................................... 9 3.1. Strategy of food oral management ............................................................. 9 3.2. Food oral management and the tongue ......................................................... 11 4. Oral processing and food rheology ................................................................ 12 4.1. The first bite............................................................................ 12 4.2. Chewing and mastication ................................................................... 13 4.3. Oral selection ........................................................................... 15 4.4. The rheology of food breakdown ............................................................. 16 5. Swallowing ................................................................................. 18 5.1. The three phases of swallowing .............................................................. 18 5.2. Bolus formation and the criteria of swallowing ................................................... 18 5.3. Bolus deformation during the swallowing process ................................................. 20 ARTICLE IN PRESS www.elsevier.com/locate/foodhyd 0268-005X/$ - see front matter r 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodhyd.2007.11.013 à Tel.: +44 113 3432748. E-mail address: j.chen@food.leeds.ac.uk