The author has been conducting research into improving the sensory and processing properties as well as the health-promoting functions of foods, and evaluating the physiological functions of food components with agreeable sensory properties, with colleagues and students in my laboratory. Among the sensory and processing properties, expansive properties of protein-fortified breads and foaming, emulsifying and gelling properties of food proteins were improved. Among the health-promoting functions, improvement of nutritional value, inhibition of platelet aggregation, reduction in allergenicity, prevention of hepatic injury, suppression of hyperglycemia, and enhancement of calcium absorption were achieved.

Total polyphenol content of roasted Jerusalem artichoke (Helianthus tuberosus L.) increased significantly with increasing temperature and time. Maximum content at 190°C for 30 min was about 7 times higher than that of the non-heated control. Further, DPPH radical-scavenging and α-glucosidase inhibitory activities also increased, and were correlated with total polyphenol content. While caffeoylquinic acids decreased with the increase in roasting temperature and time, a novel component was produced and increased. These findings suggest that the produced component exhibited high anti-oxidative and α-glucosidase inhibitory activities. There was no significant change in inulin content until 170°C for 30 min. Hot water extracts, representing a tea-like drink, contained polyphenol and inulin with high extraction efficiency. Roasted Jerusalem artichoke can be used for tea- or coffee-like drinks and as an ingredient of cakes, breads, noodles, etc. Also, it is expected to exert an antidiabetic effect because of the high inulin and elevated polyphenol contents as well as the α-glucosidase inhibitory and anti-oxidative activities.

The effect of dietary monosodium glutamate (MSG) supplementation on the thermic effect of food (TEF) remains unclear. We investigated the differences in TEF and body surface temperature produced by meals containing equal amounts of energy but varying concentrations of MSG in 14 non-obese young female volunteers. Subjects were served a 350 kcal (1 464 kJ) test meal containing 0.5% wt. of MSG (0.5% meal), 0.25% wt. of MSG (0.25% meal), or no MSG (0% meal), and their energy expenditure and body surface temperature in the right supraclavicular region and the lower part of the 7^th rib on the left mid-clavicular line (left lower costal region) were measured over a period of 180 minutes after the start of ingestion. The AUC of TEF at 31-60 minutes after the start of meal ingestion with the 0.5% meal was significantly higher than that with the 0.25% meal and 0% meal (p<0.05). The AUC of the ⊿ left lower costal region body surface temperature at 31-60 minutes after the start of meal ingestion of the 0.5% meal was significantly higher than following ingestion of the 0% meal (p<0.05). Although the present research was carried out under limited conditions, these findings suggest that dietary intake of MSG may restrictively increase the energy expenditure and left lower costal region body surface temperature from an early period after the start of meal ingestion.

The present study aimed to examine the effects of 10-week dietary supplementation with silicon on free amino acid levels in egg yolk and on blood vessel strength in laying hens. We analyzed the levels of free amino acids in the yolk and white of eggs and blood vessel strength by high-performance liquid chromatography and tensile test, respectively. In initial experiments, 1% and 5% commercial product containing silicon had no effects on body weight, body weight gain, egg-laying rate, water intake, and food consumption relative to control. These data suggest that silicon intake at the evaluated concentrations was minimally toxic in the laying hens. The levels of aspartic acid, threonine, and alanine were significantly higher in the yolk of eggs laid by the hens receiving 5% dietary silicon product supplementation than in those laid by hens receiving 1% silicon product. In addition, blood vessel strength of the descending aorta was significantly higher in the 5% silicon product treated group than the control group. These results indicate that dietary supplementation with silicon might have beneficial effects on egg yolk taste and blood vessel strength in laying hens.