Imidazole dipeptides are believed to have the ability to alleviate fatigue and improve cognitive function. We developed a production procedure to isolate and purify imidazole dipeptides from animal extracts. The highly purified imidazole dipeptides obtained by this method are almost tasteless, odorless, and free of impurities such as sodium and creatinine, making them functional food ingredients. We conducted a clinical study using the highly purified imidazole dipeptides and found that ingestion of a drink containing three antioxidants: 400 mg imidazole dipeptides, 300 mg ascorbic acid, and 20 mg ferulic acid for 8 weeks improved the oxidative injury of peripheral blood lymphocyte DNA in middle-aged and elderly men. Furthermore, elderly persons with mild cognitive impairment who were given imidazole dipeptides at a daily dose of 1 g for 12 weeks showed improved scores on both the global clinical dementia rating and the mini-mental state test. From these findings, it was suggested that highly purified imidazole dipeptides may be a potential food ingredient for preventing lifestyle-related diseases.

One of the methodologies for avoiding the deterioration of labile food and biological substances during drying is to embed the labiles in amorphous matrix of sugar. In a series of the authors’ studies, various sugars were first compared for the stabilizing effect on proteins in freeze-drying as well as the physicochemical properties in the amorphous state. Based on the experimental results, three generally accepted hypotheses on the protein stabilization by amorphous sugar matrix (water substitution hypothesis; glassy state hypothesis; partition effect) were merged into the compromised one. Next, in order to further improve the protein stabilization technique, the remaining enzyme activities after freeze-drying in the presence of various classes of substances were analyzed. The combination of disaccharide with polysaccharide(s), certain types of surfactants (e.g., sugar esters), and proteinaceous substances were found to exhibit markedly high protein stabilizing effect. Furthermore, the amorphous-sugar-based matrix was applied to homogeneously encapsulating oil droplets and nanoparticles during freeze-drying, which successfully avoided the aggregation of the particulates and the dropout from the resulting dried objects. The application of amorphous sugar matrix was expanded to the solid dispersion of hydrophobic flavors at molecular level, by utilizing the finding on the over-saturation of sugars in an organic solvent.

The size, morphology, and distribution of the internal structure of ice cream, such as ice crystal, bubble, and solid content, were determined in samples prepared at four different overrun levels using a cryogenic microtome spectral imaging system (CMtSIS) and X-ray computed tomography (X-ray CT) at the synchrotron facility SPring-8. Ice cream samples were prepared at four overrun levels and the mean values of the percent overrun by weight (OR) were 11.5%, 22.7%, 44.3%, and 73.8% for very low, low, medium, and high overrun levels, respectively. Percent overrun by volume (ORVc for CMtSIS and ORVx for X-ray CT) was also evaluated for the samples. The means of ORVc values obtained using CMtSIS were 10.5%, 42.8%, and 77.7% for very low, medium, and high overrun levels, respectively, whereas the means of the measured OR were 11.5%, 44.3%, and 73.8%, respectively. An ORVc-3D of 14.8% was obtained by incorporating the volume of bubbles in the 3-D image using CMtSIS for the ice cream sample with 12.7% OR. For high OR (73.8%) ice cream, the ORVx values ranged from 68.8% to 75.5% with a mean of 71.3%; whereas the value of the corresponding ORVc by CMtSIS was 77.7%. For low OR (22.7%) ice cream, the ORVx values ranged from 17.8% to 25.3% with a mean of 21.7%.

“Miang” is a type of post-fermented tea in northern Thailand, which is produced by lactate fermentation. The fermentation process is similar to that of Awa-bancha, which is a type of Japanese post-fermented tea from Tokushima. However, the processing procedures for the Miang and Japanese post-fermented teas are different. Miang is classified into two types based on its fermentation period. Mian-Faat (astringent Miang) is produced after fermentation for several weeks to one month. Mian-Som (sour Miang) is produced after fermentation for several months. Additionally, a part of Miang production process includes fungal fermentation. In general, the leading process of Miang processing is lactate fermentation by lactic acid bacteria. Among the post-fermented teas, Miang has the highest production rate. However, most individual producers are small-scale produces. Although the basic procedure of Miang production is the same, certain details vary depending upon the production area and producers. Microbial control, particularly the control of lactic acid bacteria, in Miang production is extremely important for its stable and continuous production. However, in several cases, Miang production is based on individual experience. Recently, biodiversity of microorganisms was discovered. Therefore, understanding the Miang production in each production area is essential for the production of unique regional Miang.

The solubility of carthamus red, red pigment from safflower, in aqueous ethanol largely depended on the ethanol concentration, and it was the highest near 60 and 70% (v/v) ethanol. Discoloration of carthamus red in aqueous ethanol was monitored under temperature-programmed heating conditions where the temperature of test solution raised linearly with time to evaluate the activation energy and frequency factor. The activation energy and frequency factor did not depend on the ethanol concentration, suggesting that ethanol does not affect the discoloration mechanism. The activation energy was 78 ± 5 kJ/mol. The increase in absorbance at 390 nm during discoloration of carthamus red correlated with the decrease in absorbance at 520 nm. This fact also suggests no effect of ethanol on discoloration mechanism of carthamus red.