Understanding the relevance of in-mouth food processing. A review of in vitro techniques

Oral processing of food is the first step in the eating process. Although the food undergoes a number of changes during mastication that influence the subsequent steps, this stage has very often been neglected in studies of digestion, bioavailability, flavor release, satiety potential, glycemic index determination, etc. The present review draws on different sources such as nutrition, medicine, phoniatry and dentistry to explain some in vitro oral processing methods and techniques that could be transferred to food technology studies to mimic in vivo comminution, insalivation, and bolus formation, describing, as a necessary reference, the respective in vivo physiological processes they attempt to imitate. Developing a deeper understanding of all the aspects of in-mouth process will help food technologists to give this crucial step the necessary attention its due importance and to consider better ways to incorporate it into their studies. •Oral processing of food is so complex that faithful reproduction in vitro is impossible.•To plan reliable in vitro experiments it is first necessary to understand what happens in the mouth.•Instrumental comminution gives good results in terms of particle size.•Artificial saliva formulations mimic chemical and rheological characteristics of human saliva.•Instrumental visualization and characterization of the food bolus are important for understanding swallowing.