Consuming rice as the staple, 0.95 million tons of rice bran is produced annually in Japan as a by-product from the rice milling process. Bran is used in several applications such as animal feed and fertilizer for mushroom cultivation, but most of it has been discarded as an agricultural waste although it contains various functional substances, such as γ-oryzanol, ferulic acid, sterol, wax, ceramide, phytin, inositol and protein. It could be considered a scarcely used but promising resource. As such, continuous efforts have been dedicated to exploring its effective utilization. In this context, functionalities of the substances contained in the bran are summarized, and our attempts for improving functionality, improving ease of use, and exploring new applications are presented.

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The purpose of this research was to study the effect of milk powder fortification with different forms of iron. Following fortification, the levels of milk fat and several functional foods were determined, as well as the effects of these functional foods on iron bioavailability. The functional foods quantified were isomalto-oligosaccharides (IMO), fructo-oligosaccharides (FO), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). The level of milk fat was found to be 0.3, 1.5, and 3.5% in test samples fortified with ferrous sulfate (FS), ferric chloride (FC), and a mix of 50% FS and 50% FC (MIX), respectively. The iron bioavailability of the samples was estimated by determining the dialyzable ferrous iron (DFe (II)), total dialyzable iron (DTFe), and nondialyzable ferrous iron (NDFe (II)) following enzymatic hydrolysis (pepsin, pancreatin-bile salt) and dialysis. The results show that the order of iron bioavailability among the iron compounds is FS, MIX, and FC, with a level of 3.5% fat providing the best iron bioavailability. Furthermore, IMO appears to depress iron bioavailability, whereas EPA improves iron bioavailability in all the iron fortified milk samples.

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Previous studies analyzing black tea constituents have been carried out primarily in regards to theaflavins, thearubigins, catechins, and caffeine. In this study, four major theaflavins, total amino acid, total polyphenols, caffeine, eight major catechins, gallic acid, theanine, glutamic acid, γ-aminobutyric acid, three major free sugars, oxalic acid, and water soluble substances were determined for 12 different kinds of black teas produced in several countries of the world. Also infusion color indicators and pH were measured. There was wide variation found in the content of constituents among the teas tested, and the content ranges of oxalic acid, gallic acid, three kinds of sugars and three kinds of amino acid were newly suggested. The content of total theaflavins showed negative regression with L values and a high positive regression with values for red color degree of infusion.

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The turbidity of dashi (soup stock) prepared using various dashi extraction conditions, as well methods for its minimization, were studied with the goal of producing a clear soup from fushi (boiled, smoke-dried fish fillet) shavings. With respect to extraction levels, dashi turbidity and crude fat content were greatest in the first soup stock extraction, successively decreasing in the second and third extractions. With respect to extraction time, dashi turbidity and crude fat content gradually increased with increased extraction time. Almost all of the extracted components in the soup stock were extricated during the first extraction or the initial period. Dashi turbidity can be minimized by adjusting the pH of the extraction water, using organic acid close to the isoelectric point of the fushi protein. This proved to be an effective method for suppressing dashi turbidity. In contrast, adjusting the pH of the stock away from the isoelectric point (either acidic or basic) resulted in significantly increased dashi turbidity. Additionally, utilization of the dashi bag method, whereby soup stock is extracted from fushi shavings encased in a bag, significantly decreased dashi turbidity and crude fat content, even though the content of other extracted components was not significantly altered. Scanning electron microscopy (SEM) observations of fushi shavings revealed that the movement of fushi shavings inside the dashi bag was restricted. This could explain why fat globules from the fushi did not disperse, resulting in decreased turbidity. The dashi bag method was an effective method for minimizing dashi turbidity.

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An easy analytical technique to determine the trace element composition of pumpkin seeds by energy dispersive X-ray florescence (XRF) analysis has been developed. Since the trace element compositions of pumpkin seeds reflect the characteristic compositions of the cultivation soils (i.e., the geographic origin of the pumpkin), the XRF technique was used to distinguish between pumpkins grown domestically and abroad. Pumpkin seed samples produced in Japan or imported from New Zealand, Mexico, and Tonga were used as samples, and were freeze-dried and pressed into disks after pulverization. The measurement conditions of an XRF spectrometer equipped with 3-dimentional polarization optics were optimized to carry out accurate quantitative analysis. As a result, linear calibration curves were obtained, and the measured concentrations of a standard sample were in good agreement with those determined by ICP-AES/MS analysis. A total of 118 pumpkin samples were analyzed quantitatively and the results were subjected to multivariate analysis for 12 elements (P, Ca, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Mo, Ba) to discriminate the four geographical origins. LDA models were established based on the results, allowing the discrimination of the four origins of the pumpkin seeds with 70∼80% accuracy. The present study shows the advantages of XRF analysis, which only requires an easy sample preparation procedure, over ICP-AES/MS analysis. We foresee future applications of the XRF technique to the widespread analysis of foods.

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We examined the inhibition of angiotensin-I converting enzyme (ACE) and nicotianamine levels in 80 kinds of vegetables. Of the species examined, ACE inhibition was observed in the majority of samples, but not in the Poaceae, which had relatively low concentrations of nicotianamine. Nicotianamine contents per 100 g dry tissue were the highest in Aralia elata. Comparisons of nicotianamine contents among the families analyzed revealed that members of the Araliaceae contained significantly more nicotianamine than members of the Liliaceae (p<0.001) and Poaceae (p<0.05). Interestingly, although the strength of ACE inhibition in the vegetables assayed was relatively large, marked ACE inhibition was observed in Asparagus officinalis, despite not containing any nicotianamine.

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Shiikuwasha (Citrus depressa Hayata) is produced in the northern area of the main Okinawa island, the southern most region of Japan, and is a typical Japanese citrus along with Tachibana (Citrus tachibana). The seed of Shiikuwasha contains high concentration of limonoid glucosides, including limonin glucoside and nomilin glucoside, which has anti-tumor activity. Synephrine, a well-known enhancer of lipid metabolism, is also present in the fruit peel. The most notable feature of Shiikuwasha, among citrus fruits harvested commercially in Japan, is its high concentration of polymethoxylflavones, such as nobiletin (NBL), tangeretin and sinensetin. These are present in the peel, where NBL is predominant. Many studies have demonstrated that NBL possesses various biological properties such as anti-carcinogenic, anti-inflammatory and hepatoprotective activities. The ingestion of Shiikuwasha paste decreases plasma glucose level in laboratory animals, such as mouse and rat, as well as human volunteers. Study of the metabolism, by animal and human liver microsomes and cytochrome P450 of NBL shows the presence of 4’-OH, 7-OH, 6-OH metabolites, as well as the novel metabolites 3’ and 4’-diOH NBL. These results indicate that Shiikuwasha is an attractive foodstuff from the perspective of health promotion. Furthermore, in order to maintain Shiikuwasha authenticity, methods distinguishing between Shiikuwasha and Calamondin were developed using a unique phloretin glucoside and certain polymethoxyflavones as chemical markers, as well as Shiikuwasha chloroplast DNA.

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Shiikuwasha (Citrus depressa Hayata) is a well-known traditional citrus fruit from Okinawa, with over 200 cultivars and varieties reported. The harvest season of Shiikuwasha is extensive, from August to February, and Shiikuwasha has a unique usage pattern. Unripe fruit, harvested in August and September, is used for cooking, while partially ripe fruit, available from October to December, is used for machining (mainly for juice) . Ripe fruit with reduced acidity is available in January and February and is used unmodified. Polymethoxylated flavones (PMFs) are characteristic components of Shiikuwasha. Depending on harvest time and variety, alterations in juice quantities, citric acid concentrations, and PMFs were observed. Most applications of Shiikuwasha involve juice processing. Notably, the efficiency of Shiikuwasha juice production is only about 50%. Many useful components are contained in the peel, and remain in the residue. A comparison of extraction methods revealed that a multi-stage extraction recovered more useful components. According to marketing research, consumer demand exists for products of Shiikuwasha as a seasoning. Therefore, we are developing applications (especially as seasonings) for juice residue containing essential oils and PMFs.

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