The possibility of use of taste sensors equipped with lipid/polymer membranes as one of the techniques which evaluate the taste of Honkakushochu was investigated. First, in order to determine chemical composition of a standard sample, the inorganic component of Honkakushochu was analyzed. The most abundant cation was sodium ion and the richest anion was chloride ion. These ions are considered to be brought in from the mother water used for dilution of Honkakushochu. Next, the measurement with sufficient reproducibility became possible by preparing the standard sample for the taste sensor suitable for evaluation of Honkakushochu. Measuring 41 kinds of Honkakushochu including rice, barley, sweet potato, buckwheat, brown sugar shochu and awamori using 8 taste sensors enabled to classify them based on their materials. Moreover, visual expression was able to be obtained about the taste patterns. Analyses of the data obtained from the taste sensor using the statistical techniques such as principal component analysis and cluster analysis suggested that the taste sensor could be useful for new product development or process control of Honkakushochu.

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An angiotensin-converting enzyme (ACE) inhibitor, nicotianamine, was purified from Hayatouri (Sechium edule) by using some ion-exchange column chromatographies. Crystal of nicotianamine (19.8 mg) was finally obtained from 75 kg of Hayatouri. The chemical identification by IR, NMR and MS spectral analysis were carried out, and the data agreed with those of nicotianamine reported by Kristensen et al. The quantitative analytical method of nicotianamine in various resources was established by using the isolated nicotianamine. An ion-pair chromatography of reversed-phase HPLC with 0.1 mol/L SDS elution buffer (pH 2.6) afforded good separation and linearity of calibration curve when o-phthalaldehyde was used for labeled reagent for fluorescence detection. Concentrations of nicotianamine in various vegetables were determined by this method. Nicotianamine concentrations of Hayatouri (Sechium edule), Seri (Oenanthe javanica), Ashitaba (Angelica keiskei), Moroheiya (Corchorus olitorius), Kureson (Nasturtium officinale), Nigauri (Momordica charantia), Soybean (Glycine max) and Soybean milk were determined to be 0.010±0.0014, 0.012±0.0028, 0.017±0.0028, 0.022±0.0021, 0.037±0.0035, 0.015±0.0021, 0.074±0.0106 and 0.090±0.0106 mg/g, respectively. As we have established the method of nicotianamine quantitative analysis, we are planning and starting the study of absorption of this compound into the blood from the intestine and about the effect on renin-angiotensin system of hypertension.

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Eleven sulfur-containing flavor precursors in garlic bulbs were quantitatively determined by high performance liquid chromatography (HPLC) method using a strong cation exchange (SCX) column, a UV detector (a photo diode array detector) and 10 mmol/L KH₂PO₄ (pH 2.50) as a mobile phase. The determinants were S-alk(en)yl cysteine derivatives, S-methylcysteine S-oxide (methiin), (+)-S-(2-propenyl) cysteine S-oxide (alliin), (-)-S-(2-propenyl) cysteine S-oxide (3-(R)-2-propenylsulfinyl-L-alanine ; allo alliin), S-(E-1-propenyl) cysteine S-oxide (isoalliin), 5-methylthiomorpholine-3-carboxylic acid S-oxide (cycloalliin), S-(2-propenyl) cysteine (deoxyalliin), N-(γ-glutamyl)-S-methyl cysteine, N-(γ-glutamyl)-S-(2-propenyl) cysteine, N-(γ-glutamyl)-S-(E-1-propenyl) cysteine, N-(γ-glutamyl)-S-(2-propenyl) cysteine S-oxide and N-(γ-glutamyl)-S-(E-1-propenyl) cysteine S-oxide. Among eleven garlic samples, constituents of the flavor precursors were compared one another. In this study, average contents of isoalliin and cycloalliin in the garlic were determined 0.13% and 0.16%, respectively (dry wt.). allo Alliin and N-(γ-glutamyl)-S-(2-propenyl) cysteine S-oxide were found in all specimens analyzed, and average contents of allo alliin and N-(γ-glutamyl)-S-(2-propenyl) cysteine S-oxide in the specimens were 0.06% and 0.16% respectively (dry wt.). The above two compounds were considered to be native constituents from conditions of the sample treatment in this study.

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Tea catechins have been recognized as blood lipid-lowering components. They are easily epimerized by heat treatment in the manufacturing of canned and bottled tea beverages. This study aimed to investigate the effect of heat-treated green tea extract (approximately 50% of catechin is isomers) on the lipid metabolism in hamsters fed a high fat diet, in comparison with parent green tea extract. Three groups of hamsters were given a purified diet containing 20% lard and 0.1% cholesterol for 6 weeks. The control group received the control diet, while the other two groups received either 0.8% tea extract (TE) diet or 0.8% heat-treated tea extract (HTE) diet, respectively. Supplementations with TE and HTE resulted in reducing the plasma total cholesterol at 4-6 weeks and triacylglycerol at 6 weeks, compared to each control value. The total cholesterol concentration in the liver declined in both catechin groups. Excretion of fecal neutral steroids was significantly increased in HTE groups. These results suggest that the lowering effect of cholesterol in hamster plasma by catechins is due to an increase in fecal excretion of neutral steroids, and that the hypolipidemic effect of HTE is equal to or greater than that of TE.

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Steamed and dried sweet potato is one of the Japanese traditional foods. Since the import of sweet potato products is increasing recently, the quality improvement of steamed and dried sweet potato is required. In recent years, the phenomenon that the central part of the steamed sweet potato becomes white in the manufacturing process of steamed and dried sweet potato came to be seen. In order to solve this problem, two experiments were carried out in the real manufacturing process of steamed and dried sweet potato. When the steam pressure of boiler was raised to 1.1kgf/cm² from a general level of 0.8kg/cm², the white spots of steamed sweet potato disappeared within a shorter time. Moreover, under the pressure of general level of 0.8kgf/cm², by letting sweet potatoes pass through hot water of an iron pot, generating of white spots were able to be prevented and steaming time was apparently shortened. Furthermore, by raising slowly steaming temperature and heating it enough, hydrolysis of sweet potato starch was promoted and retrogradation of the starch was prevented. Based on these numerical analyses, the control technology of steaming which could manufacture the sweet and soft product of excellent in quality was developed. It depended for the manufacturing process of steamed and dried sweet potato on the traditional experiences until now. These results were able to show technologies numerically and it was able to use for preventing of white spots generation. Based on these research results, the processing technology of high value-added of steamed and dried sweet potato was developed.

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The removal of dissolved oxygen in sudachi juice was examined by nitrogen gas pressurization. The direct pressurization of sudachi juice with nitrogen gas decreased the amount of dissolved oxygen in it. When sudachi juice was compressed directly with nitrogen gas, more oxygen could be eliminated by applying higher nitrogen gas pressure and by taking more time. Repetition of pressurization and depressurization with nitrogen gas could shorten the time to remove oxygen : when the compression of 10MPa at 30°C for 30s was repeated 3 times, the dissolved oxygen reduced to less than 1mg/l. Furthermore, the amount of dissolved oxygen could be decreased to 0.02mg/l by the continuous repetition of pressurization and depressurization treatment : 7 times×20s. From the facts described above, we may conclude that the repetition of pressurization and depressurization of liquid food with nitrogen gas is very effective to remove the dissolved oxygen in it. On the basis of an organoleptic test, it was found that the flavor of sudachi juice could be retained even if the compression and decompression was repeated under the following conditions ; pressure : 10MPa, temperature : 30°C, time : 1min (20s×3, 30s×2, 1min×1). Since the compression treatment of sudachi juice with nitrogen gas can get rid of the dissolved oxygen with holding its flavor, this method can be applied to the long-term preservation of sudachi juice without deterioration of its quality.

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In order to evaluate the effect of γ-ray irradiation on starch, near-infrared absorption spectra of four groups of starch samples, control, 10, 20 and 30 kGy irradiated, were measured. By the preliminary analysis, it was revealed that 1702 and 2100 nm were effective in predicting the irradiation dose on starch. On the other hand, samples were divided into calibration and validation set. The multi-regression analysis of the calibration set was carried out with adopting 1702 or 2100 nm as the first wavelength, and the resulting calibration curves were named calibration A and B. Using these calibration curves, the irradiation dose of the validation set was predicted. Although the accuracy of the prediction was poor, it seemed that the non-irradiated and the irradiated samples could be discriminated by an appropriate borderline. Therefore, a new irradiation index was defined as non-irradiated=0 and irradiated=1. In the same way as the case of four groups, calibration C and D, in addition, calibration E, which using 1702 nm only, were developed and the irradiation index of the validation set was predicted. Although there were a few samples that could not be accurately predicted with calibration C and D, there was only one wrong discrimination with calibration E and its prediction accuracy was 96.2%.

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The flavonoid contents in the vegetables have the possibility to vary according to seasons. The flavonoid contents about 15 kinds of vegetables circulated in June were examined by HPLC after hydrolysis. In addition, the amounts of quercetin and luteolin in the green pepper during the year were studied with the main production area ; Miyazaki and Kochi. The content of quercetin in green pepper, was 3.15±1.77 mg (aggregate average) and luteolin content was 8.15±4.10 mg per 100 g of fresh weight. Flavonoid contents were increased in October to December, and the tendency to decrease in May to June. The relations with the amount of the ultraviolet rays irradiation was suggested. Moreover, a significant difference was observed among homes at time when a lot of contents were different. The contents of quercetin in June and in January in vegetables (kale, komatsuna, spinach, chin-gen-sai, and perilla) were not different significantly except for kale. Therefore, it was concluded that the changes of the amount of flavonoid in the vegetables were two ways, one of which was few changes and the other showed the maximum content in autumn during year.

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