To clarify the physiological effects of dietary Chinese yam (Nagaimo) on colon cancer in vivo, the effects of dietary Nagaimo on 1,2-dimethylhydrazine (DMH)-induced aberrant crypt foci (ACF) formation in the large intestine of mice were investigated. After 8 weeks of feeding raw or boiled Nagaimo and DMH administration, DMH-induced ACF formation was found to be significantly suppressed in the large intestines of all mice. DNA microarray analysis showed that levels of apoptosis-inducing gene expression in the large intestine of animals fed dietary Nagaimo were increased in comparison to those fed the control diet. The results of the present study clearly demonstrated that DMH-induced ACF formation was inhibited in the mouse large intestine by dietary Nagaimo intake. Daily ingestion of Nagaimo may thus serve to suppress colon carcinoma in humans.

View full abstract

We investigated the rheological and swallowing properties of agar gel dispersed in xanthan gum, guar gum, starch paste and water for use in food products for the elderly. Texture measurement and dynamic elasticity were selected as indicators of rheological properties and subjective sensory evaluation was carried out using a 5-level rating method. The flow rate of a bolus in the pharynx was determined using ultrasonography after chewing for 5 and 30 times. The hardness of the agar gel dispersed in xanthan gum paste was the lowest of the samples tested and cohesiveness was the highest. Its rheological and swallowing properties and maximum flow rate were not affected by the mixing ratio in the paste or the amount of chewing. For agar gel dispersed in guar gum paste, the hardness and storage modulus (G′) decreased with increasing amount of chewing, whereas the maximum flow rate increased. The hardness and G′ of the agar gel dispersed in starch paste decreased with increased chewing, but the maximum flow rate increased. On the other hand, the maximum flow rate and the hardness of the agar gel dispersed in water were the highest among all samples, even after chewing. According to subjective measurement, the hardness of all samples significantly decreased as the mixing ratio in the paste increased. The ease of swallowing the xanthan gum and guar gum mixtures was not influenced by the mixing ratio, and was similar for both. These results indicate that rheological and swallowing properties of the agar gel dispersed in xanthan gum paste were the least influenced by chewing and by the mixing ratio among the four kinds paste of paste.

View full abstract

Physiological function of breads made with the centrifugal supernatants of sweet potato shochu distillery by-products (SDBS) was determined from the viewpoint of its effective utilization in breads. SDBS supernatants derived from the Koganesengan sweet potato with yellow flesh and the Murasakimasari sweet potato with purple flesh were tested in this study. Both SDBS supernatants were low in calories, with various kinds of nutritional and functional ingredients. Sensory evaluation and content of functional components such as γ-aminobutylic acid, citric acid, and polyphenolic components were higher in the SDBS breads than the control. SDBS breads showed significantly higher DPPH radical scavenging activity than the control, reflecting the polyphenolic content. The resultant sweet potato SDB is approved as a food material, which can be used to produce healthier foods.

View full abstract

The effect of drying temperature on the antioxidant activity of lemon balm (Melissa officinalis) leaves was investigated. Lemon balm leaves were dried with a ventilation dryer at 45°C, 55°C and 65°C, followed by milling. Among the three different temperature treatments, drying at 45°C resulted in the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, which is an index of antioxidant activity. The concentrations of polyphenols and rosmarinic acid were also highest in the sample treated at 45°C, suggesting that these antioxidants play an important role in the DPPH radical scavenging activity of the dry powders. On the other hand, when considering the use of dry lemon balm leaves as herbal tea, the 45°C-, 55°C- and 65°C-dry powder was extracted with hot water and DPPH radical scavenging activity was measured for each. All of the hot water extracts showed some extent of DPPH radical scavenging activity ; however, the highest activity was noted in the extract from the 45°C-dry powder. The concentrations of polyphenols and rosmarinic acid in hot water extracts were also highest in the 45°C-treated sample. These observations suggest that 45°C is the best drying temperature for retaining high antioxidant activity of lemon balm leaves in herbal tea production.

View full abstract

We examined the effective utilization of food waste soybean broth. Lactic acid bacteria added to the soybean broth were shown to produce γ-amino butyric acid (GABA). Lactic acid bacteria inoculants from the 1∼500 stock strains maintained in our laboratory were tested for efficient production of GABA. Addition of the lactic acid bacteria that efficiently produced GABA to the soybean broth resulted in the production of 3.5mM (36mg/100ml) GABA. In addition, high levels of GABA (46∼79mg/100ml) were produced by adding glutamic acid to the soybean broth at 0.05∼0.1% (w/v). In functional tests, soybean broth was shown to have high ACE inhibitory activity and DPPH radical scavenging ability, and also to have functionality of α-glucosidase inhibition activity and α-amylase inhibition activity. By experimenting with making bread with the addition of a lactic acid fermentation liquid that includes GABA, we tried to utilize this material as a food ingredient.

View full abstract

A toxicity study was conducted on fucoxanthin (FX) purified from Undaria pinnatifida. Evaluation was made following the repeated oral dosing of purified FX (≥95% purity) to rats for 28 days. In the 28-day, repeated oral dose test, purified FX did not show obvious toxicity. However, significant increases in total cholesterol and high-density lipoprotein cholesterol (HDL-C) levels were observed in the blood when the dose of FX was 10 mg/kg/day or higher.

View full abstract

We compared the adhesiveness to dental materials of low-adhesive chewing gum designed to not adhere to resin prosthetic materials and ordinary chewing gum those two kinds of chewing gum through instrumental measurement and questionnaire survey. 1) Adhesiveness measurement : We prepared plungers made of dental acrylic resin, stainless steel, or ivory as models of acrylic material, alloyed metal, which is used in dental care, and natural tooth and measured the adhesiveness of chewing gum using these plungers with a rheometer. In the case of the acrylic resin, adhesiveness of low-adhesive chewing gum was one-fifth of ordinary chewing gum. Both kinds of chewing gum showed markedly lower adhesiveness with stainless steel or ivory plungers. 2) Questionnaire of the sensory adhesiveness of two kinds of chewing gum : The low-adhesive chewing gum showed lower adhesiveness than ordinary chewing gum. The results of the questionnaire significantly matched the values of adhesiveness measured with a rheometer. These results suggest that the method of adhesiveness measurement used in this study can accurately evaluate sensory adhesiveness of chewing gum. Further, these findings suggest that low-adhesive chewing gum could be chewed while avoiding excess adhesion in people who have undergone dental treatment.

View full abstract