Structural Changes Within a Biscuit Bolus During Mastication

Abstract

Solid food undergoes drastic structural changes during its transformation into a cohesive bolus, which play a key role in the perception of different textures during mastication. This article describes the structural changes in biscuits during mastication through particle agglomeration. Apparent particle size and bolus moisture content were measured at different chewing stages by image and gravimetric analyses. The microstructure of the ready-to-swallow bolus was also examined with light microscopy and cryo-scanning electron microscopy (cryo-SEM). The results reveal that moisture content increased at a parabolic rate during mastication, and the absorbed saliva increased apparent particle size and decreased particle number through agglomeration. Furthermore, both cryo-SEM and light microscopy indicate that a majority of the solid particles in the ready-to-swallow bolus were individual starch granules. The results from cryo-SEM also suggest that saliva composition varied locally within the final bolus, thereby implying that laminar mixing governs bolus formation during mastication. PRACTICAL APPLICATIONSIn materials science it is well-known that the properties of a material are related to its structure. This concept can also be applied to the food bolus: the structure of a bolus determines its mechanical and rheological properties. These properties are perceived by senses within our mouths during mastication and translate to the perception of food texture. Hence, texture perception cannot be fully understood without analyzing bolus structure. This article also suggests that bolus structure is related to the type of mixing that operates within the mouth. Identifying the mechanisms involved in mastication will contribute towards a better understanding of texture perception, and can be applied in computational models of food breakdown and flavor release. This knowledge will allow solid food structures to be designed to enhance sensory appeal or follow a particular breakdown path in health food applications. 1988;Knecht 1990;Prinz and Lucas 1997;Bornhorst and Singh 2012). Throughout this process, food texture and bs_bs_banner A journal to advance the fundamental understanding of food texture and sensory perception Journal of Texture Studies ISSN 1745-4603 89 Journal of Texture Studies 45 (2014) 89-96

Impact of the Breakdown Behavior on Chinese Traditional Stewed Pork with Brown Sauce: Physical Properties Using Microstructural Analysis

“…Some images implied a glassy, brittle phase was present between the granules, while others indicated a porous network surrounded them. These results were similar to the mastication conditions of biscuits bolus [17]. This could be explained by oral chewing behavior, including gelling and emulsification with mastication breakdown and saliva secretion.…”

“…Apparent particle size in the latter mastication was higher than at the early stages for the lean layer bolus. This could be explained by the saliva rate being added to the food bolus structure [17]. Compared with the masticated lean layer bolus, the fat layer boluses are composed of particles of smaller size.…”

“…The proposed inhomogeneity of the bolus before the swallowing point provides a model for the type of mixing involved in mastication. Chaotic mixing according to the subject's individual chewing sequence could decrease heterogeneity by repeatedly stretching and folding the inhomogeneous layers [17]. The large-scale saliva gradually narrowed the long object and entered the food continuous phase.…”

Bolus matters: the influence of food oral breakdown on dynamic texture perception

“…Agglomeration coincided with the perception of a paste-like biscuit rather than the perception of individual particles. 75 This suggests that dry foods need to be broken down and agglomerated by saliva to be swallowed, whereas foods with a higher water or fat content mainly need to be broken down in smaller pieces to be safely swallowed. We conclude that breakdown patterns and pathways strongly depend on the type of food and its properties.…”

In vitro digestion of bread: How is it influenced by the bolus characteristics?

“…Population exhibited a spectrum of chewing behavior and chewing results (Chen, 2014). Chewing results were quantified as the physical characteristics of food boluses, such as moisture content (Motoi, Morgenstern, Hedderley, Wilson, & Balita, 2013), particle size (Rodrigues, Young, James, & Morgenstern, 2014), texture (Wada et al, 2017), and rheology (Le Bleis, Chaunier, Della Valle, Panouillé, & Réguerre, 2013). A direct link between the oral processing results (e.g., bolus particle size) and nutritional outcomes (e.g., glycemic response) was established in studies of starch-based solid food including rice (Ranawana, Monro, Mishra, & Henry, 2010) and pizza (Zhu, Hsu, & Hollis, 2013).…”