Viscosity Differences Between Thickened Beverages Suitable for Elderly Patients with Dysphagia

Relationship between rheological properties, sensory perception, and overall acceptability of thickened liquids for dysphagia in young and old healthy individuals

This study investigated the relationship between rheological properties, sensory perception, and overall acceptability in healthy young and old groups for dysphagia thickened liquids. Unflavored (UTL) and flavored (FTLP) thickened liquids were prepared using tap water or pomegranate juice at 10 different viscosity levels. The rheological properties were then evaluated via syringe flow test and line spread test (LST). When the apparent viscosity levels of UTL and FTLP were similar, the syringe test and LST results were also similar, indicating consistent flow behavior. Sensory perception evaluations showed that the young group better distinguished viscosity differences between stages compared to the old group. Regarding overall acceptability, the old group preferred samples with higher apparent viscosity than the young group. Principal component analysis and k-means cluster analysis were used to explore correlations between variables and classify thickened liquids into four groups. This can serve the foundation for standardized texture grades of dysphagia thickened liquids, considering rheological characteristics and sensory profiles.

Effects of adding milk to fermented black mulberry (Morus nigra L.) juice on its antioxidant activity in C2C12 cells and changes in volatile flavor compounds during storage

This study assessed the impact of milk on the bioactive compounds, physicochemical properties, antioxidant activity, ROS inhibition, and volatile flavor compounds of fermented black mulberry juice (FBMJ). Firstly, the results showed that 25% concentration of milk was the most suitable for preparing FBMJ-Milk. Compared to the control group, the addition of milk significantly increased the SOD activity and antioxidant capacity, as well as enhanced the total phenolic content (TPC) and SOD storage stability. Secondly, HS-SPME-GC-MS combined with OPLS-DA analysis identified 49 compounds in FBMJM, including 12 esters, 6 acids, 1 ketone, 2 aldehydes, 19 alcohols and 9 other compounds. During the storage, the levels of ethyl ester compounds decreased significantly, while the degradation of ester produced some acid and alcohol compounds. The findings revealed that the addition of milk was beneficial for maintaining the antioxidant stability of FBMJM during storage and enhancing the richness of product flavor.

Rheological Properties and Stability of Thickeners for Clinical Use

The adaptation of liquids for patients with dysphagia requires precision and individualization in the viscosities used. We describe the variations of viscosity in water at different concentrations and evolution over time of the three compositions of commercial thickeners that are on the market (starch, starch with gums, and gum). By increasing the concentration in water, the viscosity of gum-based thickeners increases linearly, but it did not reach pudding texture, whereas the viscosity of the starch-based thickeners (alone or mixed with gums) rapidly reaches very thick textures. We modeled the viscosity at different concentrations of the four thickeners using regression analysis (R2 > 0.9). We analyzed viscosity changes after 6 h of preparation. The viscosity of gum-based thickeners increased by a maximum of 6.5% after 6 h of preparation, while starch-based thickeners increased by up to 43%. These findings are important for correct handling and prescription. Gum-based thickeners have a predictable linear behavior with the formula we present, reaching nectar and honey-like textures with less quantity of thickener, and are stable over time. In contrast, starch thickeners have an exponential behavior which is difficult to handle, they reach pudding-like viscosity, and are not stable over time.

Physical and sensory properties of lemon-flavored acidic beverages formulated with nonfat dry milk during storage

Sensory and physical properties of 2 lemon-flavored beverages with 5% and 7.5% wt/wt nonfat dry milk (NFDM) at pH 2.5 were studied during storage. The 2 beverages had similar volatile compounds, but the 5% NFDM had higher aroma and lemon flavor, with a preferred appearance by consumers due to the lower turbidity and viscosity. After 28 d of storage at 4°C, lemon flavor decreased in the 5% NFDM beverage but was still more intense than the 7.5% one. During 70 d of storage, no microorganisms were detected, and the beverages were more stable when stored at 4°C than at room temperature according to changes of physical properties measured for appearance, turbidity, color, particle size, zeta potential, rheological properties, and transmission electron microscopy morphology. Findings of the present study suggest that NFDM may be used at 5% wt/wt to produce stable acidic dairy beverages with low turbidity when stored at 4°C.

Instrumental and sensory techniques to characterize the texture of foods suitable for dysphagic people: A systematic review

The interest to characterize texture-modified foods (TMFs) intended for people with oropharyngeal dysphagia (OD) has grown significantly since 2011. Several instrumental and sensory techniques have been applied in the analysis of these foods. The objective of the present systematic review was to identify the most appropriate techniques, especially for the food industry and clinical setting. The search was carried out in three online databases according to the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" (PRISMA). Across the multiple trials reviewed, Texture Profile Analysis and the Uniaxial Compression Test were most used as the instrumental technique for solid foods, and the Back Extrusion Test for fluid and semisolid foods. All trials used descriptive analysis as the sensory technique. However, the experimental conditions of the trials lacked standardization. Consequently, the results of the trials were not comparable. To properly characterize the texture of TMFs intended for OD by each technique, an international consensus is needed to establish standardized experimental conditions. Methods based on these techniques should also be validated by collaborative studies to verify repeatability, replicability, and reproducibility.

Dysphagia thickeners in context of use. Changes in thickened drinks’ viscosity and thixotropy with temperature and time of consumption

Dysphagia patients might need to thicken drinks. The viscosity of these thickened drinks varies among commercial thickeners and drinks compromising the ingesta safety. The aim of this study was to investigate how temperature and resting time affect the rheological properties of thickened drinks. Four commercial thickeners were used to thicken water, coffee, orange juice, and milk at two concentration levels used in dysphagia drinks (nectar and pudding). To study the effect of temperature, flow curves of thickened drinks at 10°C and 50°C were obtained and to study the effect of resting time, flow curves of thickened drinks at 25°C were obtained at different times (0, 30, and 60 min). All samples displayed shear‐thinning and time‐dependent behavior (thixotropy or antithixotropy). The effect of temperature on viscosity values and relative thixotropic area (RTA) depended on the thickener and the drink. Overall, apparent viscosity showed higher values at 50°C than 10°C, especially in thickeners containing starch and in drinks with higher soluble solids (milk and orange juice). This was attributed to the water absorption of pregelatinized starch granules favored by temperature. Antithixotropy was mainly observed at pudding concentration for the starch‐containing thickeners, and decreased with temperature. The effect of resting time on apparent viscosity and RTA depended also on the drink and thickener. Mostly, apparent viscosity values increased with resting time and antithixotropic behavior decreased. Both effects, increase in viscosity and decrease of antithixotropy with time, indicated that thickening action was being developed over the resting time.

Psyllium (Plantago ovata Forsk) in frozen banana pulp: Influence on rheological, nutritional and sensory characteristics

A frozen banana pulp with functional properties was developed and characterized in this work. For this, 0 g, 3 g, 5 g and 7 g of psyllium in 100 g of banana pulp were added. The use of this fiber in industrialized products can contribute to the nutritional enrichment of the products and provide functional benefits already acknowledged, such as lowering LDL cholesterol, lowering blood glucose, increasing satiety and relieving constipation. According to the World Health Organization, vegetable consumption should be increased, as it reduces the risk of chronic diseases. The main purpose of this work was to incorporate psyllium in frozen banana pulp to develop a healthy product. The samples were evaluated through chemical analyses, rheological properties and sensory testing with Check-All-That-Apply questions (CATA). The addition of psyllium had a significant effect not only on the viscosity but also on the sensory and nutritional properties of the frozen banana pulp. This study indicated that the production of frozen banana pulp with psyllium is viable, as it has desirable nutritional and sensory characteristics which can contribute to the maintenance of health.

Institutionalized elderly are able to detect small viscosity variations in thickened water with gum-based thickeners: should texture classifications be reviewed?

BACKGROUND

The prevalence of dysphagia is very high in institutionalized elderly. Knowledge of the rheological and sensory characteristics of the various thickeners in elderly is limited, although it has been seen that there are differences between the rheological behaviors of gum-based thickeners with different composition. Moreover, we have not found sensory studies of viscosity in institutionalized elderly. Our hypothesis was that viscosity ranges established by the scientific societies, such as the National Dysphagia Diet Task Force (NDD), seem to be very wide and individuals might be able to detect small differences within the same texture range. The objectives of our study were 1) comparing the rheological characteristics of two commercial gum-based thickeners with different composition, dissolved in water under standard conditions, and 2) perform a sensory analysis (with both adults and institutionalized elderly) to detect different viscosities within the same texture (nectar and honey).

METHODS

Two commercial thickeners based on gums (NC and RC) were studied analyzing their viscosity in water with different concentrations (shear rate: 50 s^- 1; temperature: 22-25 °C). A sensory analysis involving 26 elderly and 29 adult controls was carried out to evaluate whether differences within nectar and honey textures among gum-based thickeners could be distinguished.

RESULTS

As the shear rate increases, viscosity decreases (non-Newtonian and pseudoplastic behavior). At the same concentration, each thickener produces a different viscosity (p < 0.05). Institutionalized elderly detected viscosity differences in nectar range of 49.9 (2.5) mPa·s (p < 0.05) and 102.2 (4.7) mPa·s (p < 0.0001). They also detected viscosity differences in honey texture range of 134.6 (9.7) mPa·s (p < 0.05) y 199.3 (9.2) mPa·s (p < 0.0001). Their caregivers also detected viscosity differences in both viscosity ranges (p < 0.0001) and with greater intensity than the elderly in honey texture (p: 0.016).

CONCLUSIONS

Our results suggest that the accepted viscosity ranges by NDD for the different textures might be too wide because institutionalized elderly and their caregivers are able to discern small differences in viscosity in nectar and honey textures. Gum-based thickeners with different composition showed differences in viscosity capacity, so they are not interchangeable.

Investigation of the effects of different beverages on the disintegration time of over-the-counter medications in Saudi Arabia

Full disintegration of Oral solid dosage forms is critically important to achieve reliable clinical performance of the drug. Tablets/capsules are supposed to be taken with a full glass of water; however, many patients do not follow this recommendation as they administer their medications with beverages other than water. This study aims to assess the impact of different commonly consumed beverages in Saudi Arabia on the disintegration times of common over-the-counter (OTC) medication tablets and capsules in the Kingdom of Saudi Arabia. Five immediate release OTC drugs were chosen: Fevadol®, Solpadeine®, Ralaxon®, Artiz ®, and Brufen®. The disintegration times of these medications were assessed using a disintegration test in five beverages: Coca-cola, arabic coffee, orange juice, buttermilk and an energy drink. Times were compared to the disintegration time in water under two temperature conditions (37 °C and 5 °C). All beverages significantly increased the disintegration times of fevadol, solpadeine, and relaxon in comparison with water. The same was found for burfen, except that arabic coffee did not significantly increase disintegration time (p > 0.05). The disintegration time of artiz tablets was also significantly influenced by all beverages, except for Coca-cola and the energy drink, which had no significant impact on the disintegration time. The tested beverages should not be used as substitutes for water when ingesting medications. Patients should be advised to avoid consuming beverages other than water with therapeutic products. Increasing public awareness of drug-beverage interactions is needed.

Thickened Formulas Used for Infants with Dysphagia: Influence of Time and Temperature

Infant dysphagia is commonly managed using thickened formulas. Substantial research investigates thickening of a variety of beverages for adults and children, yet few studies address the unique considerations of thickened formula for infants. Understanding the consistency and behaviour of thickened formula will guide clinicians and parents to make informed decisions to minimise risk of aspiration. To investigate the effect of time and storage temperature on the flow properties of thickened formula, four formulas and two thickeners currently utilised at a major metropolitan children's hospital in Australia were tested in combinations, at refrigerated and room temperatures. Their flow properties were measured at three time-points (baseline, 1 h, 24 h) using the International Dysphagia Diet Standardisation Initiative (IDDSI) Flow Test, the current clinical standard for classifying drinks based on flow properties. A combination of paired t tests, Wilcoxon Signed-Rank tests, repeated measures analysis of variance (ANOVA) and Cohen's d was used to statistically compare flow properties and determine the significance of the observed data. At baseline, 98% (n = 48) of the thickened formula bottles were measured as thinner than the "mildly thick" IDDSI category to which they were prepared. Conversely, at 24 h, 17% were measured thicker than "mildly thick" whilst 10% measured too thin for the category "mildly thick". Refrigerated samples increased in thickness more significantly over time compared to those stored at room temperature. Two of the formulas, when thickened, resulted in a foamy mixture non-compatible with IDDSI Flow Test measurement. As a result, these two formulas were not subjected to further testing. All the tested commercial products behaved differently to each other and were unstable over varying times and temperatures. This finding indicates the need for improved guidelines regarding preparation and storage of thickened fluids. Further investigation is recommended into the chemical processes underlying the observed deviations.

Exploring Tools for Designing Dysphagia-Friendly Foods: A Review

Dysphagia is a medical condition that affects normal swallowing. To prevent the risk of aspiration or choking, thickened fluids and texture-modified foods have been used for dysphagia management with the goal of slowing down the flow of liquids and protecting the airway. This article summarizes the available information about the rheological and textural parameters, the characterization of the most-used thickeners and the application of alternative texture modification technologies that are crucial to developing safe dishes for people who suffer from swallowing difficulties. Regarding rheological and textural measurements, fundamental and empirical methods are described.

Dysphagia-Related Health Information Improved Consumer Acceptability of Thickened Beverages

Most people tend to think that healthy foods do not taste good. This view could have a negative impact on the taste of the food that people eat for health. However, if health-related information is provided to avoid negative aspects, acceptability may improve. Thus, this study investigated changes in consumers’ sensory perception of thickened beverages before and after the provision of dysphagia-related health information. Sixty young (19–39 years old) and middle-aged (40–64 years old) consumers participated in two experiment sessions conducted one week apart. The first session proceeded without any information and the second provided information about dysphagia and the need for dietary modification before evaluation. Three beverages (orange juice, red bean water, and sports drink) were used in nectar-like (51–350 cP) and honey-like (351–1750 cP) forms; original beverage samples (0%) were used as the control. Consumers were asked about acceptability, liking the flavor, intensity, and general health interest (GHI). An analysis of variance was performed to show the change in flavor rating and acceptability between the two sessions. Although there were age-related differences in response to the samples, thickened beverages were rated as more acceptable, in terms of their characteristics (swallowing, viscosity, and mouthfeel) after the information was provided. There were no significant differences for the 0% samples. The mean GHI values were 3.97 ± 0.85 and 4.81 ± 0.68 for the young and middle-aged groups, respectively. High and low GHI groups were analyzed. The high GHI group showed significant differences in acceptability in the informed evaluation, whereas the low GHI group was not influenced by the information.

Assessment of oral solid dosage forms administration manner and acceptability

Taking oral solid dosage forms (OSDFs) safely and effectively is particularly important. This study aimed to determine the pattern and knowledge about the proper criteria of OSDF administration and the consumers’ preferences toward OSDF characteristics. The aims of this study were achieved by cross-sectional survey through open and closed-ended questionnaires, and the presence of the main OSDF administration recommendations of a sample of 32 OSDF drug leaflets was assessed. Based on a simple random sample of 250 volunteers, we found inadequate compliance with the OSDF medicine administration criteria. We also found an absence of the main recommendations of OSDF drug administration on most of the investigated OSDF drug leaflets. Conventional white, round tablets were found to be the most preferred type of OSDF drug. These findings can be valuable to pharmaceutical manufacturers, regulatory agencies, and pharmacists to enhancing patient awareness and compliance with OSDF administration for safe and effective drug administration.

Creating psychometric scales for perceptual assessment of fruit juices' refreshing and thickness attributes

Persons look for beverages to satisfy thirst (refresh) and feel fulfilled (thick). However, refreshing and thickness are concepts that lack a measurement instrument that captures an accurate judgment of consumers' perceptions. This research aims to propose a tool to assess consumers' refreshing and thickness expectations of fruit juices. Items were developed through a two-stage qualitative-exploratory study, followed by a quantitative study describing the scale's composition using an Item Response Theory approach. Hence, we suggest a set of items to consider when measuring both concepts from a perception task. Moreover, results show that thickness and refreshing are distinct and independent ideas. We provide a theoretical contribution defining each construct and recognizing the attributes that best describe refreshing and thickness for five different fruit juices. Our methodological contribution is creating a scale for each of the concepts. Practically, developing a thickness and refreshing scale is useful for product developers and marketers who expect to satisfy consumers' needs for soft drinks.

Influence of thickening agents on rheological properties and sensory attributes of dysphagic diet

Dysphagia is the difficulty during the progression of the bolus from the mouth to the stomach. Modifying the texture of the food is a fundamental factor for safe swallowing in patients with dysphagia since inadequate consistency can result in complications. To personalize and develop diets for dysphagia, understanding, and controlling the rheological and sensory properties of thickeners is useful. This review examines the different types of thickeners used to modify the texture of foods, as well as their influence on rheological properties and sensory attributes to efficiently manage the diet in dysphagia. The study discusses characteristics such as: hardness, viscosity, viscoelasticity, as well as sensory attributes related to rheology. The thickeners xanthan gum, methylcellulose, carboxymethylcellulose, guar gum, linseed, and chia, carboxymethylated curdlan, and konjac glucomannan were reviewed in this work. Sensory evaluations of different foods have already been carried out on some products such as: meats, carrots, soups, pates, and timbales with their modified textures. The sensory attributes measured among hydrocolloids are strongly correlated with rheological parameters. Dysphagic diets should have less hardness and adherence, but with adequate cohesiveness to facilitate chewing, swallowing to protect from aspiration and reduction of residues in the oropharynx. The use of a single type of thickener may not be ideal, their mixtures and synergistic effect can improve the viscous and elastic characteristics of foods, to obtain safe food to swallow and to improve the sensory interest of dysphagic patients. Personalized recommendations with follow-up on swallowing approaches, respecting patient's individuality, explaining thickening agents' differences would be pertinent.

Influence of the particle size and hydrocolloid type on lipid digestion of thickened emulsions

Hydrocolloids are used as stabilizing agents in order to enhance the physical stability of emulsions during their storage. However, they can also play an important role in nutrient release and bioavailability. In this context, the aim of this research was to study the effect of the emulsion type and thickener type on the physical-structural changes and free fatty acid release during in vitro digestion. Oil-in-water emulsions were prepared with different particle sizes (CE: conventional emulsions and NE: nanoemulsions) and thickening agents (starch and xanthan gum). The experimental conditions of homogenization used allowed food emulsions to be obtained at the microscale and nanoscale, with particle sizes ranging among 3.2-3.4 μm and 78-107 nm for CE and NE, respectively. The addition of thickening agents (XG and ST) modified the physical properties of emulsions (particle size, zeta potential and stability) slightly, and thickened samples with similar viscosity were obtained. The kinetics of FFAs released during the in vitro intestinal digestion showed no significant differences (p > 0.05) in the digestion rate among samples; however, emulsion and thickener types decreased the final extent of free fatty acids, being more evident for those samples with starch. Xanthan gum kept the particle size of nanoemulsions stable during the oral and gastric phases, which promoted the release of FFAs during the intestinal phase. Therefore, xanthan gum could be used as a thickening agent of nanoemulsions exerting a minor impact on their lipid bioaccessibility.

Application of a Manufacturer's Guideline and an IDDSI-Driven Guideline to Thickening of Some Non-water Beverages: A Rheological Study

This study aimed to evaluate an existing liquid-thickening guideline provided by a major manufacturer of thickener in Hong Kong and to provide directions for the implementation of the IDDSI framework. Fifteen participants who are naïve to liquid thickening were required to prepare thickened liquids samples from three drink bases (i.e., Milk-tea, Chinese tea, and Herbal tea) at two target consistency levels (i.e., mildly and medium/moderately thick) based on two guidelines (i.e., the manufacturer's guideline and an IDDSI-driven guideline). Viscosities of the samples were measured rheologically to reflect liquid consistency. The manufacturer's guideline resulted in distinguishable viscosities at the two consistency levels (F(1, 35.464) = 113.764, p < 0.001, η_p² = 0.802), as well as different viscosities in different drink bases (F(1.267, 35.464 = 92.951, p < 0.001, η_p² = 0.769). Comparison between the manufacturer's and the IDDSI-driven guideline showed that the later resulted in more viscous liquid samples in all drink bases and at both consistency levels. The difference between the two guidelines was statistically significant (F(1,28) = 35.137, p < 0.001, η_p² = 0.557). Following only the manufacturer's guideline when thickening non-water beverages may lead to discrepancy between the resultant and prescribed consistencies. Thus, it should be considered inadequate to ensure swallowing safety. The effect of drink base should be emphasized to patients and caregivers, and pre-serving tests should be introduced. Despite similar classifications and terminologies used between the current local framework and the IDDSI framework, measures should be taken to avoid potential confusions and associated threats to swallowing safety.

The impact of modification techniques on the rheological properties of dysphagia foods and liquids

Modifying food and the textures of food has been done for decades within the food science and technology field. More recently, modifying the texture of foods has been used to manage swallowing disabilities (dysphagia). Swallowing disabilities are often associated with dehydration and malnutrition, thus nutritional intervention has formed part of serving texture-modified diets. The question remains whether these modification techniques are viable for individuals with swallowing disabilities living in majority world countries. This study used two modification methods on a widely used specialized nutritious food (SNF) to determine whether it may be modified and used in dysphagia management. The techniques had to be ergonomic and economically appropriate for individuals with swallowing disabilities living in majority world countries. The International Dysphagia Diet Standardization Initiative's (IDDSI) standards were used to determine whether the texturally modified SNF is safe for swallowing. Rheological measurements were performed to determine apparent viscosity and structure recovery of each sample. The effects of two modification techniques, aeration and particle separation, on the rheological properties of the SNF were also measured and analyzed. It was determined that both milk and water could be used with this SNF to create a dysphagia diet, but only under certain conditions. The overall results indicated that heating the samples increased the apparent viscosity and exacerbated lumping. Room temperature samples had less lumps and could be classified to the desired levels of the IDDSI (Level 2 and Level 4). Using a whisk to aerate the samples reduced lumps significantly and using a sieve to separate particles of liquid samples eliminated lumps. This study provides new data on how texture modification techniques and the IDDSI framework could be adapted to individuals living in majority world countries. By using modification techniques that are ergonomic and economically viable and an SNF with longevity, this study could be useful in guiding future training of nursing staff and caregivers of individuals living in poverty or resource-constrained communities. This study also adds to the data on the rheological properties of dysphagia foods, although this study did not make use of commercial thickeners generally used in the modification of diets.

Characterizing the Dynamic Textural Properties of Hydrocolloids in Pureed Foods-A Comparison Between TDS and TCATA

Pureed foods, a compensatory diet for dysphagia, require the incorporation of hydrocolloids in order to be swallowed safely. The effect of hydrocolloid addition on textural dynamics of pureed foods has not yet been investigated. Starch and xanthan were added to levels that allowed products to meet the criteria of the International Dysphagia Diet Standardization Initiative. Nine pureed carrot matrices made with two concentrations of starch, xanthan, and their blends were characterized for textural evolution using two dynamic sensory techniques: Temporal Dominance of Sensations (TDS) and Temporal Check-All-That-Apply (TCATA). Each test, with four replications, was conducted with 16 panelists. Results indicate that purees were divided into two groups based on sensory responses--grainy and smooth were the primary differentiating attributes for these two groups. Grainy was associated with starch-added samples, while samples with xanthan (alone and in blends) were smooth and slippery. For both groups, thickness was perceived during the first half of processing, adhesiveness in the second half of oral processing, and mouthcoating was perceived toward the end of processing. A comparison of results from these tests showed that both TDS and TCATA gave similar information about texture dynamics and product differentiation of pureed foods.

Comparison of two methods to categorize thickened liquids for dysphagia management in a clinical care setting context: The Bostwick consistometer and the IDDSI Flow Test. Are we talking about the same concept?

The Bostwick consistometer and the International Dysphagia Diet Standardization Initiative (IDDSI) Flow Test are both proposed methods to measure and categorize thickened liquids for dysphagia management. The objectives were to: (a) compare the Bostwick consistometer reference values used in clinical settings and the IDDSI reference values of thickened liquids suggested for nutrition care plans in the management of dysphagia when measuring commercially available preprepared thickened liquids; (b) explore the relationship between the two methods; (c) assess the interchangeability; (d) document the intra-rater reliability. Preprepared thickened liquids (n = 32) were measured twice with the Bostwick consistometer and 3 times with the IDDSI Flow Test, using a rigorous methodology. A registered dietitian nutritionist and a registered nutrition and dietetic technician performed the measurements. The Pearson's correlation coefficient was calculated to explore the relationship between the two methods. Using a linear regression equation, back-calculations of the IDDSI Flow Test values were done, based on the experimental Bostwick results. Interchangeability was assessed by documenting the level of agreement between the results with a Bland and Altman graphical analysis. Intraclass correlation coefficients calculation and a Bland and Altman graphical analysis were performed to assess reliability. The strong correlation (r = -.93, p < .001) between the IDDSI Flow Test and the Bostwick consistometer measurements suggests that they measure flow rate in a similar manner, but not exactly the same, as confirmed with the Bland and Altman graphical analysis. Thus, they produced results that are not interchangeable. However, both tests show excellent intra-rater reliability (ICC ≥ 0.99) when using a rigorous methodology. PRACTICAL APPLICATIONS: Thickened liquids are used to manage oropharyngeal dysphagia. Clinicians need to provide quality assurance/quality control (QA/QC) support in the selection or production of thickened liquids as well as staff training or patient education regarding these products. Methods and classification have been proposed to measure and categorize thickened liquids for dysphagia management, such as the line spread test, the Bostwick consistometer method, and the IDDSI Flow Test. Although empirical, these methods are more accessible to clinicians than viscometer or rheometer assessments. Clinicians need to understand the limitations of these techniques as neither appear to capture the full extent of consistency for potential beverages available on the market or produced in-house. In this article, we compare the Bostwick consistometer and the IDDSI Flow Test methods and classifications and propose a standard operating procedure in order to maximize the quality of results. We point out the large variations in consistency levels of commercial preprepared thickened liquids in light of the absence of evidence of clinical outcomes associated with either proposed methods or consistency classifications.

Use of Textured Thin Liquids in Patients With Dysphagia

PURPOSE

The goals of this article are to explore the use of textured thin liquids for dysphagic patients who require thickened liquids and to illustrate their impact on hydration and patient satisfaction.

METHOD

A retrospective evaluation of textured thin liquids was completed using patient data looking at laboratory values relevant to the detection of dehydration (blood urea nitrogen, creatinine, sodium) and patient satisfaction (using a clinician-generated questionnaire) on different modified liquid textures. In addition, the viscosity for all liquids was tested using a rheometer.

RESULTS

Measurements show that the viscosity of the textured thin liquids examined in this pilot study are significantly lower than the viscosity of nectar-thick liquids and fall within the "thin" category as defined by the National Dysphagia Diet guidelines. Patients on honey- and nectar-thick liquids had laboratory values signifying dehydration, whereas those receiving the textured thin liquid consistency were within the normal range for all laboratory values. Importantly, when consuming textured thin liquids, patients reported significant improvement in their satisfaction related to their thirst.

CONCLUSION

The results of this pilot study highlight the consequences of common thickened liquid dietary recommendations and of the potentially beneficial clinical application of textured thin liquids for patients with dysphagia as well as the need for future prospective research.

Rheological characterization of thickened protein-based beverages under different food thickeners and setting times

The effects of different setting times (15-120 min) on the rheological properties of cold thickened protein-based beverage (PBB) samples prepared with different xanthan gum (XG)-based food thickeners were examined. In this study, four commercial XG-based food thickeners (coded A-D) and three commercial PBB products (whole milk, skim milk, and soybean milk) were used to prepare thickened PBB samples at a 3% thickener concentration. The fastest increases in η_a,50 values of thickened PBB samples were observed at 15 min, and at longer time periods their η_a,50 values gradually increased or remained constant with an increase in setting time (15-120 min). The magnitudes of the rheological parameters (η_a,50 , K, G', and G″) of thickened PBB samples with thickener A were significantly higher compared with those with other thickeners (coded B, C, and D). The flow and dynamic rheological properties of thickened PBB samples prepared with different XG-based thickeners were significantly different (p < .05), demonstrating that their rheological properties were greatly affected by the type of PBB and thickener as well as the setting time.

PRACTICAL STATEMENTS

Food thickeners have been commonly used in the preparation of various thickened fluids with desirable rheological properties for dysphagic patients to elicit an optimal swallow response. However, among various thickened fluids, there is limited rheological information on cold thickened protein-based beverage (PBB) (e.g., whole milk, skim milk, and soybean milk) prepared with various xanthan gum (XG)-based thickeners. Our flow and dynamic rheological results showed that the flow and viscoelastic properties of the thickened PBB samples prepared with different food thickeners were dependent on the PBB type, thickener type, and setting time. These rheological results presented in this study will provide both thickener manufacturers and clinicians with valuable information for thickened PBB products with desirable rheological properties for safe and easy swallowing. New knowledge of the different rheological characterizations of thickened PBB can be practically applied to develop the commercial dysphagia thickeners suitable for PBB in food industry.

Sensory characteristics of liquids thickened with commercial thickeners to levels specified in the International Dysphagia Diet Standardization Initiative (IDDSI) framework

Sensory characteristics are important for the acceptance of thickened liquids, but those of liquids thickened to the new standards put forth by the International Dysphagia Diet Standardization Initiative (IDDSI) are unknown. This research sought to identify and rate the perception of important sensory properties of liquids thickened to levels specified in the IDDSI framework. Samples were made with water, with and without added barium sulfate, and were thickened with a cornstarch or xanthan gum based thickener. Samples were characterized using projective mapping/ultra-flash profiling to identify important sample attributes, and then with trained descriptive analysis panels to characterize those attributes in non-barium and barium thickened liquids. Three main groups of attributes were observed. Taste and flavor attributes decreased in intensity with increasing thickener. Thickener specific attributes included graininess and chalkiness for the cornstarch thickened samples, and slipperiness for the xanthan gum samples. Within the same type of thickener, ratings of thickness-related attributes (perceived viscosity, adhesiveness, manipulation, and swallowing) at different IDDSI levels were significantly different from each other. However, in non-barium samples, cornstarch samples were perceived as thicker than xanthan gum samples even though they had similar apparent viscosities at 50 s^-1. On the other hand, the two thickeners had similar perceived thickness in the barium samples even though the apparent viscosities of cornstarch samples were higher than those of the xanthan gum samples. In conclusion, IDDSI levels can be distinguished based on sensory properties, but these properties may be affected by the type of thickener and medium being thickened.

Texture Adaption in Dysphagia: Acceptability Differences Between Thickened and Naturally Thick Beverages

PURPOSE

The aim of the study was to investigate differences in the acceptability between thickened and naturally viscous beverages.

DESIGN

This was an exploratory, cross-sectional study.

METHODS

One hundred twenty-eight healthy volunteers rated overall liking/disliking of a selection of each of three thickened drinks and three beverages of natural viscosity pre- and postconsumption. Mean ratings were subjected to statistical analysis done with t tests.

FINDINGS

Although all naturally thick beverages evoked good expectations, there were significant differences in expected acceptance of thickened fluids concerning the kind of beverage. Postconsumption of naturally thick beverages were rated significantly better than thickened.

CONCLUSIONS

The findings suggest an alternative offer of naturally thick drinks and waiver of thickening water when viscosity adaption is needed.

CLINICAL RELEVANCE

The sufficient and safe oral fluid intake in dysphagia requires compliance to dietetic recommendations. Naturally thick beverages can contribute to increase the appeal of texture-modified diet.