Exploring Tools for Designing Dysphagia-Friendly Foods: A Review

Development of soft food gels from high-methyl pectin-protein conjugates via acid- and heat-induced crosslinking for dysphagia-friendly applications

This study developed pea protein isolate (PPI)-high-methyl (HM) pectin conjugates via the Maillard reaction to enhance PPI's functionality as a texture modifier for dysphagia-friendly soft food gels. Conjugation at 1:1, 2:1, and 4:1 protein-to-pectin ratios significantly improved structural flexibility, physicochemical characteristics, and functional properties. Fourier Transform Infrared Spectroscopy (FT-IR) confirmed successful conjugation through shifts in amide I and II bands, while SDS-PAGE revealed higher molecular weight aggregates, indicating effective crosslinking. Circular Dichroism (CD) spectroscopy showed a reduction in β-sheet content (from 47.41 % to 16.15 %) and an increase in α-helices (from 0 % to 12.70 %), enhancing solubility (from 1.79 % to 100 %) and reducing surface hydrophobicity (from 74.52 % to 18.16 %). These structural changes facilitated improved protein dispersion and stable gel network formation, enhancing gel cohesiveness and softness, key attributes for dysphagia-friendly textures. Conjugate-incorporated gels exhibited softer textures than firmer control gels. Acid-induced gels formed soft, easily deformable matrices, while heat-induced gels produced firmer structures, accommodating different dysphagia severity levels. International Dysphagia Diet Standardization Initiative (IDDSI) assessments classified these gels as Level 6, ensuring safe swallowing. Rheological analyses revealed non-Newtonian shear-thinning behavior, while SAXS confirmed uniform nano-aggregation. Overall, PPI-HM pectin conjugates demonstrate potential as safe, functional solutions for texture-modified foods targeting dysphagia management.

The possibility of the computer simulation-assisted IDDSI framework for the development of thickened brown rice paste

Increasing requests for thickened fluid food are demanded with population aging, while the limited information provided by the International Dysphagia Diet Standardisation Initiative (IDDSI) is insufficient for food development. Recently, the introduction of computer simulation seems to be able to overcome this dilemma. Here, a thickened fluid system (xanthan gum and konjac glucomannan, XG and KGM) at different ratios was kept at the same IDDSI level 3. An obvious synergy was observed in the ratio of 1:9 (XG: KGM) with high surface tension, zero-shear viscosity, firmness and cohesion, and thus was used to prepare the brown rice paste. From computer simulation, the brown rice pastes (0.3 % and 0.5 % thickener) splashed and that with higher thickener content resulted in more residue. The thickener content of 0.7 % provided enough viscosity and cohesion to avoid splash, and most of the bolus flowed consistently, showing the best sensory quality and swallowing properties.

Salmon protein gel enhancement for dysphagia diets: Konjac glucomannan and composite emulsions as texture modifiers

The growing prevalence of dysphagia among the aging population presents a significant challenge. Many highly nutritious foods, like salmon, are often unsuitable for the elderly due to their firm texture when heated. To address this concern, a combination of salmon myofibrillar protein (SMP), Konjac glucomannan (KGM), and different emulsion fillers-such as oil droplets, octenyl succinic anhydride (OSA)-modified potato starch emulsion, and high methoxylated pectin (HMP) emulsions-was selected to enhance the network of salmon protein gels with the aims to create potential applications as dysphagia-friendly foods. The International Dysphagia Dietary Standardization Initiative (IDDSI) test indicated that all gel samples were classified as level 5. The OSA-SMP-KGM gel exhibited notably higher cohesiveness (P < 0.05), reduced adhesion, and enhanced mouthfeel. The OSA-SMP-KGM gel exhibited a smooth surface and excellent water retention (92.4 %), rendering it suitable for individuals with swallowing difficulties, particularly those prone to experiencing dry mouth. The yield stress of OSA-SMP-KGM gel was 594.14 Pa and stable structure was maintained during chewing and swallowing (γe/γv = 62.5). This study serves as a valuable reference for developing salmon-based products that are not only highly nutritious but also fulfill the criteria for a desirable swallowing texture.

Food Processing and Nutrition Strategies for Improving the Health of Elderly People with Dysphagia: A Review of Recent Developments

Dysphagia, or swallowing difficulty, is a common morbidity affecting 10% to 33% of the elderly population. Individuals with dysphagia can experience appetite, reduction, weight loss, and malnutrition as well as even aspiration, dehydration, and long-term healthcare issues. However, current therapies to treat dysphagia can routinely cause discomfort and pain to patients. To prevent these risks, a non-traumatic and effective treatment of diet modification for safe chewing and swallowing is urgently needed for the elderly. This review mainly summarizes the chewing and swallowing changes in the elderly, as well as important risk factors and potential consequences of dysphagia. In addition, three texture-modified food processing strategies to prepare special foods for the aged, as well as the current statuses and future trends of such foods, are discussed. Nonthermal food technologies, gelation, and 3D printing techniques have been developed to prepare soft, moist, and palatable texture-modified foods for chewing and swallowing safety in elderly individuals. In addition, flavor enhancement and nutrition enrichment are also considered to compensate for the loss of sensory experience and nutrients. Given the trend of population aging, multidisciplinary cooperation for dysphagia management should be a top priority.

Understanding the health benefits and technological properties of β-glucan for the development of easy-to-swallow gels to guarantee food security among seniors

The world's population is growing rapidly and the number of elderly people with undernutrition and malnutrition is increasing. Common health problems among seniors are cardiovascular, inflammatory, gastrointestinal, and cognitive disorders, cancer, diabetes, psychological and dental problems. The food industry is trying to meet the demands of an aging society, but these efforts are not sufficient. New strategies are needed, and they demand foods development with modified textures that are easy to swallow, such as gels suitable for seniors. Depending on the specific needs of the elderly, bioactive compounds with health benefits should be included in food systems. Novel foods may play an important role in the prevention, maintenance, and treatment of age-related diseases. One of the most studied bioactive compound is β-glucan, a polysaccharide with approved health claims confirmed by clinical trials, such as "β-glucan contributes to the maintenance of normal blood cholesterol levels" and "the consumption of β-glucan from oats or barley contributes to the reduction of postprandial glucose spikes." In this review, the health benefits, and technological properties of β-glucan for the development of senior-friendly ready-to-swallow gels were described. In addition, some patents and studies conducted in connection with the development of the gel systems were collected.

Feasibility of hydrocolloid addition for 3D printing of Qingtuan with red bean filling as a dysphagia food

Glutinous rice flour, the main component of Qingtuan, has increased adhesiveness after gelatinization and hardness after aging; this results in great challenge in swallowing if for patients with dysphagia. Dual nozzle 3D printing has great potential for developing innovative Chinese pastries with fillings that conform to dysphagia diets. In this experimental study, the gelatinization and retrogradation behavior of glutinous rice starch was improved by designing printing inks of optimal properties made with different soluble soybean polysaccharide (SSPS) additions (0%, 0.3%, 0.6%, 0.9%). The internal structure of Qingtuan was modified by adjusting different filling densities (75%, 100%) in combination with the dual nozzle 3D printing. The objective of these tests was to enhance the texture of Qingtuan so that it meets the requirements of International Dysphagia Diet Standardization Initiative (IDDSI). The experimental results showed that 0.9% SSPS addition could effectively reduce the hardness and adhesiveness of the Qingtuan, which met the Level- 6 -soft & bite-sized standard while lower filling density lowers both hardness and adhesiveness.

Easy-to-swallow mooncake using 3D printing: Effect of oil and hydrocolloid addition

3D printing is a promising technology for food production, capable of producing and developing personalized food products. In recent years, research on the application of 3D printing technology to create easy-to-swallow foods for the elderly with dysphagia has received extensive attention. In this study, we applied dual nozzle 3D printing technology to develop an easy-to-swallow mooncake food using a traditional Chinese food, mooncake, as a model system. We optimized the printing dough ink formulation by setting up soybean oil gradient experiments and Arabic gum gradient experiments, and then we applied the optimized dough ink as the crust of the mooncake to produce easy-to-swallow mooncakes. The experimental results show that the addition of 2.5 g of soybean oil and 0.125 g of Arabic gum could improve the texture of the dough product and reduce its hardness and adhesiveness. The mooncake produced with this crust dough ink was rated in the IDDSI texture level four, which met expectations. Therefore, this work provides insights into the development of easy-to-swallow food products.

Patients with dysphagia: How to supply nutrition through non-tube feeding

OBJECTIVE

Dysphagia has become one of the important factors that cause malnutrition in the whole age group. At present, tube feeding is still the mainstream means to solve the problem of dysphagia. However, tube feeding has physical and mental harm to people, and the ways of non-tube feeding are relatively diversified. The significance of the thickening mechanism described in some articles to solve the problem of dysphagia is not clear.

SETTING AND PARTICIPANTS

All patients with dysphagia worldwide, including oropharyngeal dysphagia (OD) and non-oropharyngeal dysphagia.

METHODS

We searched the literature in Pubmed, Web of Science and Cochrane Library and initially browsed the titles and abstracts. We reviewed the full text of the articles that met our topic, and the language of the article was limited to English.

RESULTS

We found that food thickening to a certain degree (350-1,750 cP) can reduce the complications of choking, aspiration, reflux, and other complications in patients with dysphagia, and reduce the social disorder, anxiety, and other psychological problems caused by catheterization and surgery. Significantly, food science engineers should invite clinicians to intervene in the development of specialty foods from different perspectives such as clinical pathophysiology and fluid mechanics.

CONCLUSION AND IMPLICATIONS

It is necessary to develop special foods for patients with dysphagia, which requires scientists from different disciplines to work together.

Meat texture modification for dysphagia management and application of hydrocolloids: A review

Dysphagia is a medical condition that describes the difficulty of swallowing food, and texture modified food (TMF) is the best intervention for dysphagia. The relevant guidelines to identify dysphagia food are provided by the International Dysphagia Diet Standardization Initiative (IDDSI). Developing texture modified meat is a challenging task due to its fibrous microstructure and harder texture. Various meat tenderization attempts are therefore evaluated in the literature. Meat texture modification for dysphagia is not just limited to tenderization but should be focused on safe swallowing attributes as well. The application of hydrocolloids for designing TMF has a major research focus as it is a cost-effective method and offers an opportunity for careful control. The present review focuses on the meat texture modification attempts that have been used in the past and present, with special attention to the use of hydrocolloids. Several studies have shown improvements in texture upon the addition of various hydrocolloids; however, few studies have attempted to develop texture modified meat for people with dysphagia. This area has to be further developed along with the sensory evaluations conducted with the dysphagia population, to validate the industrial application of hydrocolloids to TMF.

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.

Attitudes towards Freshly Made and Readily Prepared Texture-Modified Foods among Speech-Language Therapists, Dietitians, and Community-Dwelling Older Adults

Texture-modified foods (TMFs) are recommended for patients suffering from swallowing difficulties. Given the increasing aging population, the use of TMFs is on the rise. Research to date has focused on the nutritional value, malnutrition indices and healthcare practices in relation to TMFs, but the perception of these diets from a patient and healthcare practitioner perspective has received less consideration. This study explored how currently available TMFs (including Soft & Bite-Sized, Minced & Moist, and puree) are perceived by key stakeholders. Four types of TMFs were consumer tested: freshly made TMFs following foodservice recipes and three types of readily prepared TMFs (commercially packaged, sous-vide and hydrolysed). The selected samples were tested through five focus groups (including nine dietitians, seven speech-language therapists, and five community-dwelling older adults), which involved a sensory rating using a validated 7-point scale meal assessment tool and a semi-structured focus group discussion. Analysis was conducted using quantitative and qualitative approaches. Soft & Bite-Sized meals had significantly higher palatability ratings than others. Sous-vide meals were most suitable for Soft & Bite-Sized texture, while commercially packaged samples were most appropriate for minced moist and pureed meals. Three main themes emerged through content analysis: (1) palatability of TMFs, (2) perceived challenges with the currently available TMFs and (3) key differences in opinion between stakeholders. Freshly made TMFs were more appealing and tastier, whereas readily prepared (pre-cooked, packaged and require reheating) TMFs had a more consistent texture. The texture of all TMFs requires enhancement, particularly in pureed meals. Developing nutritious and safe TMFs for people with dysphagia requires the promotion of active insight exchange between dietitians and speech-language therapists.

High-Protein Foods for Dysphagia: Manipulation of Mechanical and Microstructural Properties of Whey Protein Gels Using De-Structured Starch and Salts

This study focuses on understanding the effect of ionic strength on the mechanical and microstructural properties of novel composite gels containing 13% whey protein isolate (WPI) and 4% de-structured waxy potato starch (DWPS). The DWPS is a physically modified waxy potato starch treated at 140 °C for 30 min under constant shear. Thermodynamic incompatibility between WPI and DWPS was observed upon the addition of NaCl (~75 mM) or CaCl₂ (10–75 mM). The combined effects of such thermodynamic incompatibility with the changes in protein connectivity induced by varied ionic strength led to the formation of distinctive gel structures (inhomogeneous self-supporting gels with a liquid centre and weak gels with paste-like consistency) that were different from thermodynamic compatible homogeneous self-supporting gels (pure WPI and WPI + maltodextrin gels). At ≥ 250 mM NaCl, instead of a paste-like texture, a recovered soft and creamy self-supporting gel structure was observed when using DWPS. The ability to generate a range of textures in WPI gelation-based foods by using DWPS under different ionic conditions, is a feasible strategy for formulating high-protein foods for dysphagia—aimed to be either thickened fluids or soft solids. Additionally, this acquired knowledge is also relevant when formulating food gels for 3-D printing.

Rheological Information of Pudding-Thick Liquids Prepared Using Commercial Food Thickeners Marketed in Korea for Dysphagic Patients According to the Manufacturers’ Guidelines

Food thickeners are commonly used to prepare thickened liquids for the management of dysphagia. The National Dysphagia Diet (NDD) thickness levels of thickened liquids prepared with commercial food thickeners are known to vary depending on the thickener type, recommended amount of thickener, thickener brand, and preparation instructions. Particularly, detailed preparation instructions must be provided by the manufacturers to achieve the correct thickness levels. However, the rheological information on product labels provided by manufacturers is typically not accurate. Here, various pudding-thick liquids were prepared by mixing commercial xanthan gum (XG)-based thickeners based on the manufacturers’ guidelines, and their rheological properties were characterized. Several thickened liquids prepared with four different XG-based thickeners (A-D) marketed in Korea did not meet the pudding-like criterion (> 1,750 mPa·s) based on the NDD guidelines. Significant differences in rheological parameter values (η_a,50, n, and G′) were also identified among the various thickened liquids. Only one thickener (thickener A) manufactured in Korea showed optimal results, which satisfied the pudding-thick viscosity range for various food liquids and also showed lower stickiness and enhanced bolus formation ability for easy and safe swallowing when compared to other thickeners (B, C, and D).