On modeling the large strain fracture behaviour of soft viscous foods

Abstract

Mastication is responsible for food breakdown with the aid of saliva in order to form a cohesive viscous mass, known as the bolus. This influences the rate at which the ingested food nutrients are later absorbed into the body, which needs to be controlled to aid in epidemic health problems such as obesity, diabetes and dyspepsia. The aim of our work is to understand and improve food oral breakdown efficiency in both human and pet foods through developing multiscale models of oral and gastric processing. The latter has been a challenging task and the available technology may be still immature, as foods usually exhibit a complex viscous, compliant and tough mechanical behaviour. These are all addressed here through establishing a novel material model calibrated through experiments on starch-based food. It includes a suitable damage initiation criterion, a damage evolution law governed by the true material's fracture toughness and a constitutive stressstrain response, all three being a function of the stress state i.e. compression, shear and tension. The material model is used in an FE analysis which reproduces accurately the food separation patterns under a large strain indentation test, which resembles the boundary conditions applied in chewing. The results lend weight to the new methodology as a powerful tool in understanding food breakdown and optimising food structures.

Fatty acid bioaccessibility and structural breakdown fromin vitrodigestion of almond particles

“…However, it is unclear whether fluid shear, hydrostatic pressure, or particle-particle grinding was responsible for particle breakdown in the HGS. 53,56 Fracture of foods during mastication has been previously reviewed, 57,58 but investigating the mechanisms of structural breakdown of solid foods in the gastric environment could be a topic for future research. In addition to particle breakdown, increased mixing of digesta could also have led to led to the higher lipid bioaccessibility in the HGS as compared to the shaking water bath models.…”

In silico trials of food digestion and absorption: how far are we?

“…Food oral processing therefore governs the size distribution of food particles that reach the stomach, which are typically up to several millimetres in size. To enhance our understanding of the relationship between food structure and oral breakdown during mastication, latest results from both finite element [25] and meshfree [26,27] three-dimensional (3D) methods are rather encouraging. When combined with experimental data from model food materials, they enabled fair predictions of crack initiation and propagation [25], and of food fragment sizes produced during chewing [26].…”

“…To enhance our understanding of the relationship between food structure and oral breakdown during mastication, latest results from both finite element [25] and meshfree [26,27] three-dimensional (3D) methods are rather encouraging. When combined with experimental data from model food materials, they enabled fair predictions of crack initiation and propagation [25], and of food fragment sizes produced during chewing [26]. This latter model, proposed by Harrison et al, used smoothed particle hydrodynamics (SPH) to predict the mechanical behaviour and breakdown of two agar gels during mastication.…”

Computer simulations of food oral processing to engineer teeth cleaning

“…Concurrently, in-vitro investigations 19–21 impose challenges in physically reproducing physiological conditions and disparate anatomies 20–22 . In contrast, recent reports 10,11 suggest that an in-silico approach can facilitate straightforward studies of food texture-size-shape to optimise cleaning efficacy for individual breeds; this would reduce the need for subjecting animals to frequent anaesthesia, as well as the need for physical food prototyping 15,23 . Specifically, virtual models based on Finite Element (FE) analysis can be developed in order to simulate how the food deforms, fractures and interacts with digital teeth representations.…”

“…In particular, the deformation and fracture patterns in the food dictate whether teeth-food interaction will reach teeth areas surrounding the gum line. Simultaneously, the food rigidity/stiffness designates firstly the chewing force magnitudes involved 11 , thus the severity of mechanical teeth-food interaction, while the food fracture toughness determines the number of chews required for food comminution and subsequent swallowing 12 i.e., the amount of teeth-food interaction per unit calorie consumption. Lastly, the diverse dental anatomy amongst breeds 13 implies variation in ways of chewing 10,14 and thus also food textural preferences 15–17 .…”