Development of a method for measuring water absorbency or release of food during mastication.

Kazuyoshi Narita,Masahiro Hayashi,Hiroaki Masunaga

doi:10.1186/s40064-015-1249-3

Abstract

Water release or absorption of food is related to ease of swallowing for individuals with difficulties in mastication or swallowing. The aim of this study was to establish methods to mechanically measure and predict water releasing or absorptive tendency during mastication. There were ten ingredients used. Six, Japanese radish, carrot, potato, salmon, chicken, and scallops were typically heated. The remaining four, apple, bread, cookies and kamaboko were used as is. Eight grams of water was added to 8 g of the ingredient, which was blended for 1 s in a mixer. After blending, the mixture was centrifuged or compressed using a texture analyzer machine. Ingredients were weighed before and after processing without water, and the percent increase in weight was calculated using the weight of the ingredients. Results demonstrated that three ingredients (Japanese radish, carrot, apple), which have strong tendencies for releasing, showed lower percent increases in weight, while two ingredients (cookies, bread), which have strong tendencies for water absorption, showed higher percent weight increases. The other five ingredients (potato, kamaboko, salmon, chicken, and scallops), which have no water releasing or absorption tendencies, showed mid-value percent increases in weight. The tendencies using all treatment methods were the same as during mastication. The percent increase in weight using two processing methods strongly correlated with increased rates of mastication, and demonstrated uncertainty equal to that of mastication. These methods may be helpful in establishing an index for ease of swallowing for classified diets in patients with dysphagia.

Highlights

When food is masticated and mixed with saliva, salivary fluid is absorbed into the food, whereas moisture contained in the food is released into the mouth as the physical structure of the food is altered
Each sample was placed in a mill mixer, blended with water that had the same weight as the sample, and compressed or centrifuged, which allowed the estimation of the level of and tendency toward water absorption and release in the mouth during food intake
The method for measuring the rate of increase in weight used in the present study is considered to allow for proper evaluation of ease of swallowing, in particular water behavior in the mouth, including release of water from food and absorption of water into food during mastication and swallowing, by classifying food into high water release, intermediate, and high absorption groups based on their characteristics

Summary

Introduction

When food is masticated and mixed with saliva, salivary fluid is absorbed into the food, whereas moisture contained in the food is released into the mouth as the physical structure of the food is altered. Of foods, including determining the surface and content of food include: (1) carefully placing food on filter paper or wiping food on filter paper (Umene et al 2015), and (2) compressing food using a creep meter (Nohara et al 2010) Another method of determining the water absorption of food is to immerse polished rice in water (Miwa et al 2002). By using these conventional methods, measuring or predicting levels of water release from food and absorption of saliva into food in the mouth during food intake at the same time is not feasible. Since conventional methods do not consider the influence of the tongue, properly predicting and understanding this influence on mastication and swallowing during food intake is difficult. We devised a new method to appropriately assess behaviors of water in the mouth during mastication and swallowing, including water release and absorption of foods, by classifying the characteristics of foods into the following three groups: (1) high water release, (2) intermediate, and (3) high water absorption, assuming (1) high water release and (3) high absorption foods are not suitable for people with dysphagia, while (2) intermediate foods are suitable

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