STUDIES OF THE ORAL CAPABILITIES IN RELATION TO BOLUS MANIPULATIONS AND THE EASE OF INITIATING BOLUS FLOW WOROUD ABDULRAHMAN ALSANEI and JIANSHE CHEN 1 School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, U.K. This article originated from a presentation given during the conference, “Food Oral Processing – Physics, Physiology, and Psychology of Eating”, held in Beaune (France) on July 1–5, 2012. KEYWORDS Bolus size, bolus swallowing, deglutition disorders, deglutition, dysphagia, maximum isometric tongue pressure, oral pressure, oral volume 1 Corresponding author. TEL: +(00)-44-113-3432748; FAX: +(00)-44-113-3432982; EMAIL: j.chen@food.leeds.ac.uk Received for Publication December 4, 2012 Accepted for Publication July 23, 2013 doi:10.1111/jtxs.12041 ABSTRACT Bolus swallowing can be a difficult task and/or highly hazardous to people with dysphagia (swallowing impairment), involving a risk of choking and airway obstruction. Food and pharmaceutical industries are under growing pressure to design and provide quality food for safe consumption by these disadvantaged populations and urgently need knowledge and a proper understanding of the con- trolling mechanisms of bolus manipulation and swallowing. In this study, physi- ological capabilities related to oral food handling, including maximum isometric tongue pressure, the volume of oral cavity, optimum bolus size, and tongue pres- sures applied during bolus swallowing were investigated. A total of 106 healthy subjects of different ages, genders and ethnic groups were involved in the investi- gation. A wide range of maximum isometric tongue pressure (from as low as 10 kPa to as high as 70 kPa) and maximum oral volume (from as low as 25 mL to as high as 116 mL) were observed. Further analysis showed that gender had no sig- nificant influence on tongue pressure and oral volume capacities. For younger adults (22–64 years), age also appears to have little effect. However, for older adults (>65 years), both maximum isometric tongue pressure and the oral volume showed a gradual decrease with the increasing of age. By investigating basic factors of bolus swallowing, this project aimed to reveal critical controlling factors under- lining the process and to test the hypothesis that, because tongue pressure pro- vides the initial driving force for bolus flow, one’s capability to generate tongue pressure could be related to the ease with which one can swallow. For this purpose, a selection of subjects with known maximum isometric tongue pressure was further invited to swallow food (bolus) of varying consistencies. A positive correlation was observed between maximum tongue pressure and the maximum consistency of bolus that one can swallow for those who had lower tongue pres- sure generation capacity (<40 kPa). However, for subjects capable of producing very high tongue pressures (>40 kPa), a tongue pressure reserve (around a third of their maximum capability) was observed during bolus swallowing. PRACTICAL APPLICATIONS This article investigates a few interesting hypothesis on the bio-mechanics of food processing, especially tongue pressure for bolus management and transfer during oro-pharyngeal swallow. Swallowing is the final stage of food oral processing and is crucial for the transportation of orally processed food (the bolus) to the stomach for further digestion and nutrient absorption. As such, safe swallowing is a major concern for many disadvantaged populations, e.g., some elderly bs_bs_banner A journal to advance the fundamental understanding of food texture and sensory perception Journal of Texture Studies ISSN 1745-4603 1 Journal of Texture Studies 45 (2014) 1–12 © 2013 Wiley Periodicals, Inc.