Performing Department
(N/A)
Non Technical Summary
Patients with dysphagia frequently reduce and/or alter dietary intake, leading to malnutrition and dehydration. This may result in low protein consumption, which is critical for maintenance of muscle function and prevention of frailty in older adults. Since dysphagics are often prescribed thickened fluids to minimize aspiration into the lungs, the focus of this project is to develop thickened fluids with added proteins. This poses a major challenge, however, since the thickening agents typically do not interact well with proteins, leading to separation of the fluid into different phases, an unappealing result. Through careful selection of hydrolyzed proteins and thickeners, protein-fortified thickened fluids will be developed for further evaluation. Specifically, these protein-fortified thickened fluids will be evaluated for their rheological properties and in swallowing biomechanics studies. Finally, computational modeling will be used to predict how fluids behave in the mouth during swallowing.
Animal Health Component
25%
Research Effort Categories
Basic
50%
Applied
25%
Developmental
25%
Goals / Objectives
The overall aim of this project is to develop and characterize protein-fortified thickened fluids for people who suffer from dysphagia.Despite the abundance of studies on thickened fluids for persons with swallowing issues, there remain opportunities for further development of more clinically-proven products with protein fortification. Thickened fluids have traditionally been characterized by a single parameter, the apparent shear viscosity at a shear rate appropriate to swallowing (30 s-1 to compare with the diagnostic standards). Recent studies suggest that other properties of these fluids may correlate better with swallowing success. Namely, the extensional (or squeezing flow) viscosity may be an important parameter of these fluids as they are swallowed. In addition, surface properties, specifically surface tension and interfacial viscosity, may influence bolus formation during swallowing. Further, previous studies have largely ignored saliva effects on fluid properties and swallowing. It is imperative that saliva interactions with the fluid be studied and characterized. A long-term nutritional goal for those who treat dysphagics is to incorporate protein into these fluids since dysphagics often are elderly people who do not get enough protein in the diet. However, phase separation between proteins and hydrocolloids at the levels needed poses a problem for developing thickened fluids with broad appeal. Finally, the time and cost of conducting swallowing studies limits the range of parameters that can be studied. If a computational model could accurately predict flow during swallowing, numerous parameters could be studied without using human subjects.
Project Methods
Objective 1: Develop protein-fortified thickened fluids and characterize their rheological properties (shear viscosity, extensional viscosity, surface tension, interfacial rheology) with and without the addition of saliva of varying mucin content. Hypothesis 1: Denatured whey proteins, through either heat or hydrolysis, will form complexes with hydrocolloids that have superior solubility as compared to native whey proteins. Hypothesis 2: Different protein-hydrocolloid combinations that form soluble complexes will not phase separate in model thickened beverages but will provide a range of rheological properties.Hypothesis 3: Like whey protein, denatured soy proteins will also form soluble complexes with some hydrocolloids.Objective 2: Examine interrelationships among rheological properties of protein-enhanced fluids (from Objective 1) made from different thickener combinations, salivary mucin content, mouthcoating, and swallowing biomechanics (oropharyngeal and bolus flow kinematics).Hypothesis 1: Higher extensional and interfacial viscosities of protein-enhanced thickened fluids would be associated with less mouthcoating and more efficient swallowing (lower bolus aspect ratio, less pharyngeal residue, increased pharyngeal transit times).Hypothesis 2: Extensional viscosity of protein-enhanced thickened fluids as compared to shear viscosity will correlate more strongly with mouthcoating and swallowing efficiency.Hypothesis 3: Participants with higher salivary mucin content will demonstrate less mouthcoating and more efficient swallowing (lower bolus aspect ratio, less pharyngeal residue) with all protein-enhanced thickened fluids compared to those individuals with lower salivary mucin content.Objective 3: Use mathematical and computer modeling to study the effect of rheological properties of protein-enhanced fluids and extent of lubrication on swallowing biomechanics (oropharyngeal and bolus flow kinematics).Hypothesis 1: The computational model developed for bolus flow mechanics will be able to predict the effects of varying extensional viscosity, shear viscosity on bolus flow outcomes.Hypothesis 2: Decreases in mouthcoating can be modeled by variations in wall boundary condition for a given bolus rheology.