71.Using Thickening Agents

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Explanation

"Thickening agents" is an umbrella term for food products that thicken liquids or other substances to make them easier to swallow. In contrast, substances that set liquids into a gelatin-like state are called gelling agents. In this module, we cover the characteristics, types, and uses of thickening agents and gelling agents, as well as using thickening agents to make semi-solidified tube feeding formulas.

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Explanation

Thickening agents are food products that can make difficult-to-swallow foods such as water easier to swallow regardless of their temperature by adding thickness to them to allow for bolus formation and modify their fluidity from the oral cavity to the esophageal orifice. Based on the ingredients used, thickening agents are broadly divided into starch-based, guar gum-based, xanthan gum-based, and carrageenan-based thickening agents.

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Explanation

This table lists the general characteristics of various thickening agents1, while a table in Slide 6 lists their respective main brand names and manufacturers. Currently, most texture modified foods use xanthan gum-based thickeners. In the lists of ingredients in their products, many manufacturers label xanthan gum as "polysaccharide thickener", so it's difficult to tell what type of thickening agent is used in a food simply by looking at the list of ingredients.

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Explanation

Here, let's look at the use of thickening agents using xanthan gum-based thickening agents as an example. When adding a thickening agent, we must be careful to prevent lumps from forming, although recently available thickening agents have enhanced dispersibility and solubility that make lumps unlikely to form. However, for xanthan gum-based thickening agents, although they dissolve easily in high-temperature foods, they are prone to forming lumps. Also, adding too much thickening agent causes foods to stick to the oral and pharyngeal mucosa.

In their Japanese Dysphagia Diet 2021 (Thickened Liquid), the Japanese Society of Dysphagia Rehabilitation classifies thickened liquids for patients with dysphagia as "mildly thick", "moderately thick", and "extremely thick", Also, for each classification, observational descriptions and measurements are listed.. Manufacturers of thickening agents publish the rough amounts of thickening agent to add to achieve these classifications. It is strongly recommended to refer to these amounts. Slide 5 shows points to watch out for when using thickening agents.

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Explanation

Here, let's look at the use of thickening agents using xanthan gum-based thickening agents as an example. When adding a thickening agent, we must be careful to prevent lumps from forming, although recently available thickening agents have enhanced dispersibility and solubility that make lumps unlikely to form. However, for xanthan gum-based thickening agents, although they dissolve easily in high-temperature foods, they are prone to forming lumps. Also, adding too much thickening agent causes foods to stick to the oral and pharyngeal mucosa.

In their Japanese Dysphagia Diet 2021 (Thickened Liquid), the Japanese Society of Dysphagia Rehabilitation classifies thickened liquids for patients with dysphagia as "mildly thick", "moderately thick", and "extremely thick"; also listed along with these classifications are observational descriptions of their respective attributes and measurements of their respective physical properties. Manufacturers of thickening agents publish the rough amounts of thickening agent to add to achieve these classifications, and it is strongly recommended to refer to these amounts. Slide 5 shows points to watch out for when using thickening agents.

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Explanation

There are dozens of thickening agents on the market, but this abundance of options can make it difficult to choose the right product for a particular patient's swallowing function. The amount of thickening agent to use also varies greatly among individual products based on the food they are to be added to. So, it's essential that we understand the characteristics of a particular thickening agent when using it. When using a thickening agent, be sure to always add the same amount needed for the patient's swallowing function and to add only the minimum amount needed.

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Explanation

When using thickening agents with chopped foods, the key is to use soup deftly to achieve a syrupy, starchy consistency. When using thickening agents with blended foods, the basic point is to pour the foods and the thickening agent into the blender together.

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Explanation

Gelling agents2 harden liquid components and are used in foods like gelatin dessert and pudding. Even a small amount of gelling agent can harden liquid; by adjusting the amount used, we can achieve a wide range of hardness, from a soft texture to a springiness like that of konjac. There are many types of gelling agents such as agar, gelatin, carrageenan, and pectin, each with their own properties. Each type of agent is used for a different purpose and must be chosen accordingly.

Jellies are generally considered suitable for patients with dysphagia, but be careful because different gelling agents result in different textures and physical properties. Some recently available gelling agents can also be used to make warm jellies.

Agar is low cohesive, doesn't melt in the oral cavity, and doesn't undergo changes in shape when passing through the pharynx. These properties may result in choking and other accidents in patients who have problems in the anticipatory stage of swallowing (attention disorders, problems with pacing, et.), patients who have problems forming boluses or other problems with oral function, and patients with problems in the pharyngeal stage of swallowing (delayed triggering of the swallow reflex, failure of laryngeal elevation, etc).

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Explanation

Gelatin is extracted by degrading hard proteins found in the bones and skin of cows and pigs by heating the proteins along with water. Gelatin jelly melts at 20-30°C. So, when gelatin jelly is taken into the mouth, the surface of the gelatin jelly is melted by body heat, making the it smooth and creating a pleasant texture as it goes down the throat. However, be careful with patients who have problems in the oral preparatory phase due to conditions such as dementia-they tend to keep gelatin jelly in the oral cavity without swallowing it, changing the physical property of gelatin jelly into water. Thanks to a recently developed type of gelatin that dissolves in cold water, gelatin jelly can now be made with cold drinking water as well.

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Explanation

Carrageenan is the most common material used in gelling agents for patients with dysphagia. Unlike agar, carrageenan is flavorless, odorless, extremely soft, and mildly elastic. Carrageenan has a gelatin-like texture and is easy to handle like agar. The description of pectin is omitted here.

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Explanation

In Slides 11 and 12 we see comparisons of different gelling agents, their brand names, and the companies that make them.

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Explanation

In Slides 11 and 12 we see comparisons of different gelling agents, their brand names, and the companies that make them.

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Explanation

Semi-solid nutrition was designed to prevent gastroesophageal reflux, diarrhea, and other complications associated with tube feeding.

A viscosity of 20,000 mPa⋅s is considered ideal for preventing gastroesophageal reflux4. The addition of 1% xanthan gum-based thickener Neo-High Toromeal III® (FoodCare Co., Ltd.) to tube feeding formula can yield a viscosity equal to 20,000 mPa⋅s, thereby preventing gastroesophageal reflux in the gastric environment. Also, because Neo-High Toromeal III® is in a liquid state when infused, it can be infused easily even into a nasogastric feeding tube as small as 8 Fr.

As well as preventing diarrhea and gastroesophageal reflux, thanks to its reduced infusion time, semi-solid nutrition can improve patients' quality of life by reducing the time they spend resting in bed (thereby effectively preventing pressure ulcers) and allowing ample time for rehabilitation.

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Explanation

We have looked at Neo-High Toromeal III® as a specific example of a thickening agent, but we can expect the same effect with another thickening agent as long as the ingredients are the same. However, due to differences among products in the volume and blending ratio of polysaccharide thickener, the exact viscosity in the stomach is not known. So, careful consideration is needed when using a different product. With tube feeding formulas, a similar level of effect can be anticipated with polymeric formulas. However, due to differences in protein flotation rate and fat flotation rate, some thickening agents may not provide sufficient viscosity, particularly thickening agents with a low protein flotation rate. With elemental and oligomeric tube feeding formulas, a thickening effect in the stomach may be difficult to achieve.

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Explanation

Thickening agents are used to produce semi-solidified tube feeding formulas via reactions of the proteins in tube feeding formulas, gastric acid, and thickening agent in the gastric environment. So, caution is needed regarding the use of agents for semi-solidification in patients suspected to have no capacity or extremely weak capacity for forming semi-solids, such as patients who have undergone total gastrectomy and patients taking proton pump inhibitors.

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References

  1. Ogoshi H: Instruction of using thickening agents. Monthly Book Medical Rehabilitation, 57: 132-139, 2005.
  2. Teshima T ed: Handbook of care of eating for elderly. Ishiyaku publisher: 52-76, 2007.
  3. Goda F: Short time injection of semi solid nutrition from G-tube. Rinsho Eiyo 106 (6): 757-762, 2005.
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