“BARLEYmax” (BM) is a variety of barley that is a superior source of dietary fiber and resistant starch. This study examined the colonic fermentation properties of BM in comparison to a conventional variety, “Hindmarsh”, relative to cellulose as a control under two experimental conditions. The residues of barley samples after hydrolysis with two digestive enzymes were tested in vitro for 48 h. In phase 1, the effects using different sample weights were examined, whereas in phase 2, the effects under various sample weights were determined considering that the resistant fraction per gram of flour is higher for BM. In phase 1, short-chain fatty acid (SCFA) concentrations of BM at 24 to 48 h of incubation were significantly higher in comparison to those of Hindmarsh. In phase 2, SCFA and ammonia concentrations were significantly higher and lower, respectively, for BM throughout the incubation period relative to Hindmarsh. From these results it can be assumed that the higher amount of the fermentable indigestible fraction in BM has more beneficial intestinal fermentation properties and leads to higher production of SCFA for an extended period.
In order to examine the applicability of using the sounds of swallowing and electromyography (EMG) to evaluate the ease of swallowing foods, the power and duration of sound signals and muscle activities required for swallowing foods were measured for foods that differed in swallowing ease. The assessed foods included potage, yogurt, pudding, and a juice and yam powder solution adjusted to the same thickness as that of yogurt. Swallowing sounds were recorded from the thyroid cartilage using a small condenser microphone, and EMGs were measured from the right anterior belly of the digastricus in 13 healthy adult men. The swallowing sounds and the EMGs of subjects who swallowed a 3-g sample were measured each time. The hardness of foods measured by Texture Profile Analysis showed an increasing tendency as the ease of swallowing increased. The relative value of the power of the swallowing sound signal was inversely correlated with the logarithm of the food sample hardness (correlation coefficient (r) ＝ -0.435, p ＜ 0.01). The duration of swallowing was not significantly correlated with the logarithm of hardness (r ＝ -0.151). The correlation coefficients for the power and duration of the EMG against the logarithm of hardness were 0.261 and 0.176, respectively, and showed no significant differences for different foods. Considering the relationship between the hardness and the ease of swallowing of different types of foods, these results suggest that the power of the sound of swallowing would be one applicable measure for determining the ease of swallowing sol-like foods.