Due to the aging of Japanese societies, people have become aware of the importance of self-managing of their health, and thus health food has been very popular in recent years. In 2013, the Ministry of Health, Labor and Welfare announced that the elongation of a health of life expectancy is of importance in order to suppress the increment of healthcare spending. Under these circumstances, the market for health foods and supplements is expected to expand. Since there are no strict regulations of the manufacturing and marketing for health foods and supplements, it is said that some products claims positive effects even in the absence of any conclusive evidence. In addition, the amounts of effective components in health foods and supplements are not shown for many products. Under these conditions, determinations of the amounts of the effective components in health foods and supplements is crucial for safety when using these products. In 2013, Consumer Affairs Agency began investigating a new certification mark system concerning the functionality of foods, and has also been going forward in the development of display methods for them. In recent years, vitamin E and polyphenol related products founded in supplements or health foods have been consumed in daily life. Although these products may make consumers think that they are more effective than those foods that contain only one effective component, there is no evidence as to whether several components interact with each other to affect their activity. Therefore, it is of great importance to precisely measure the amounts of the effective components in foods. In this research, we chose multi-component supplements that included vitamin E derivatives and polyphenols, and investigated a rapid analysis method for these active components. Vitamin Es and polyphenols have widely different polarities, and thus rapid measurements of these compounds at the same time is difficult to active by using conventional methods. Thus, we applied an ultra high-speed LC system equipped with a photo-diode array detector to determine the quantities of vitamin E and polyphenols at once, even if they have very different retention times. As a result, eight vitamin E derivatives were found to be able to be analyzed in a short time. In addition, the results of the present work suggested that health foods and supplements are analyzable by our method to provide information about containing effective compounds.
Polyphenols are widely distributed in plant foods, and are responsible for their taste, color, and health benefits. They have been proposed to play a key role in food stability and functions, owing to their ability to self-associate in a nonspecific way and to form colloids-like complexes. Although this behavior was characterized by some molecular analysis, such as NMR spectroscopy and molecular dynamics simulations, the detection of self-associated polyphenols has been difficult due to their instability and complexity. In the present study, we used catechin extract from tea as model polyphenols, and developed a new method for the detection of the self-association of tea polyphenols using native-polyacrylamide gel electrophoresis (native-PAGE). For the detection of the self-association, tea polyphenols were analyzed by native-PAGE/transblotting, followed by redox-cycling staining. The result showed that tea polyphenols were separated into the high-molecular weight region on the gel. In addition, both coomassie brilliant blue and silver staining, the general staining procedures to protein, were applicable to the analysis on the gel without transblotting. Furthermore, the association-dissociation behavior of tea polyphenols was characterized by using both the surfactant and the purified tea catechins. These results indicate that the band detected in the high-molecular weight region involves stable self-associated polyphenols. The detection and characterization of self-associated polyphenols are the important steps to evaluate the quality and functionality of foods including plant polyphenols. In the future, this method must be validated for more general purposes.
Volatile Organic Compounds (VOCs) that are contained in crude oil and natural gas are the leading cause of suspended particulates or photochemical oxidants. Especially, because benzene is a carcinogen, its environmental standards related to air is formulated. We take a variety of VOCs emission reduction measurements in the production and storage processes for oil and gas. In order to monitor those effects, we have been measuring the benzene concentration in air found in oil and gas fields by our own laboratory using a passive sampler method originally used for indoor measurements of VOCs. Since we had planned to outsource these analysis duties to a measurement certification inspection organization, we and that organization had collaborated to carry out comparison experiments between laboratories and between types of passive samplers, for one year. The adsorbent of the passive sampler that we used in the comparison experiment was a carbon molecular sieve and activated carbon. The results indicate a good correlative relationship for both comparison experiments.