Swallowing disorders, or dysphagia, affect a large part of the population due to factors such as degenerative diseases, medication side effects or simply age-related impairment of physiological oropharyngeal function. The management of dysphagia is mainly handles through texture-modified foods of progressively softer, smoother, moister textures, depending on the severity of the disorder. Rheological and physiological-related properties of boluses were determined for a group of five older persons (average age, 74) for a set of texture-modified foods: bread, cheese and tomato and the combination into a sandwich. The softest class was gel food, after which came a smooth timbale; both were compared to boluses of regular food. The subjects chewed until ready to swallow, at which point the bolus was expectorated and measured regarding saliva content, linear viscoelasticity and shear viscosity. The results were compared to those of a previously studied younger group (average age, 38). The general physiological status of the subjects was determined by hand and tongue strength, diadochokinesis and one-legged standing and showed that all subjects were as healthy and fit as the younger group. Age-related properties such as one-legged standing with closed eyes and salivary flow plus bolus saliva content were lower for the older group, but the average chews-until-swallow was surprisingly also lower. Consequently, bolus modulus and viscosity were higher than for the younger group. Overall, the intended texture modification was reflected in bolus rheological and physiological-related properties. Bolus modulus, viscosity, saliva content and chews-until-swallowed all decreased from regular food to timbale food to gel food. © 2023 The Authors.

As life expectancy increases so do age related problems such as swallowing disorders, dysphagia, which affects 10%–30% of people over 65 years old. For dysphagia patients the texture and rheological properties of the food, and the bolus, is critical to avoid choking and pneumonia. Texture modified foods, timbals, are often served to these patients due to their ease of swallowing. The main concern with these foods is that they do not look visually alike the food they replace, which can decrease the patient’s appetite and lead to reduced food intake and frailty. This study aims to improve both the visual appearance of texturized food as well as the energy density and fiber content of the timbal formulation. 3D scanning and additive manufacturing (3D Printing) were used to produce meals more reminiscent of original food items, increasing their visual appeal. Rheology was used to ensure the original flow profile was maintained as the timbal was reformulated by reducing starch contents and partially replacing with dietary fibers. The amount of starch was reduced from 8.7 wt% in the original formulation to 3.5 wt% and partially replaced with 3 wt% citrus fiber, while maintaining properties suitable for both swallowing and 3D printing. The resulting formulation has improved nutritional properties, while remaining suitable for constructing visually appealing meals, as demonstrated by 3Dprinting a chicken drumstick from a model generated with 3D scanning.

Macroalgae are a rich source of dietary fibre, protein, lipids and bioactives. However, more research is needed to understand how processing methods impact macroalgae techno-functional properties. In this work, aqueous suspensions of the fibre-rich brown algae Laminaria digitata were prepared by conventional food processing methods. The impact of sequence of processing steps (thermal and mechanical treatments), and heating time (15, 30 and 45 min), on volatile aroma composition were investigated. Changes in volatile composition were monitored with headspace GC-FID/MS analysis. Our results showed that both parameters impacted the volatiles profile of the suspensions. From an overall volatile perspective, short heating times (90 °C for 15 min) led to similar profiles, independently of the sequence of thermal and mechanical treatments. However, longer heating times induced a larger release of several aldehydes, specific for each processing method. Our results bring new insights on the volatile composition of suspensions of Laminaria digitata, which are related to flavour properties, and aid design of food products containing seaweed. © 2022 The Authors

Preparation of a bolus is a complex process with both food comminution and degree of lubrication with saliva playing an important role in a safe swallow. Swallowing disorders i.e. dysphagia, are especially present among the elderly population and often lead to choking and further health complications. The aim of this research was to investigate the relationship between the perception of ease of swallowing in the elderly and the rheological parameters of particulated foods, using broccoli purees as a model system. Particulated foods can be described as a concentrated dispersion of plant particles in a fluid phase. The effect of the fluid phase (Newtonian vs. shear thinning) and dispersed phase (plant particles with different size distribution and morphology) on the rheological properties of simulated boli was studied by characterising shear viscosity, viscoelasticity, yield stress, extensional viscosity and cohesiveness. Ease of swallowing and mouthfeel were evaluated by a semi trained healthy elderly panel (n = 19, aged 61 to 81). Ease of swallowing was correlated with the presence of yield stress and extensional viscosity in the bolus, characteristic of boli with xanthan gum as the fluid phase. Although the properties of the fluid phase played a dominant role in the ease of swallowing, compared to the dispersed phase, both components played a role in the rheological properties of the bolus and the perception of ease of swallowing by the elderly panel. These results provide insights into the design of personalised foods for populations with specific needs such as those suffering from swallowing disorders.