Oral tribology: Providing insight into oral processing of food colloids

Food oral processing research has attracted a great deal of attention in the last few decades owing to its paramount importance in governing sensory appreciation and pleasurable experience of consuming foods and beverages and eventually regulating nutrient intake. A range of physiologically-controlled unit operations from first bite, to particle size reduction, mastication with saliva, bolus formation, swallowing to generation of oral residues occur during oral processing of solid foods across a range of time and length scales resulting in various physical, biochemical and psychological consequences. Tribology is the study of friction and lubrication, and it has emerged as a key tool to deconvolute these complex processes and provide insights into the physics of oral processing and sensory perception. This review provides an overview of “oral” tribology including experiments in the last decade on food colloids and lubrication theories, and highlights a perspective on how the field is evolving to address various food science challenges. This includes current and forecast future applications of tribology in designing healthier foods, creating sustainable alternatives without compromising mouthfeel, tackling food counterfeiting and tailoring foods for aging populations. We also examine a suite of advanced complementary techniques such as imaging, scattering, and adsorption using specific examples from allied fields that would be useful to uncover frictional dissipation in food systems in the future. The perspectives provided in this review thus represent an exciting glimpse of what tribology can offer, which may become a routine and integral step in food colloidal design in the future.