Effects of hot air temperature and velocity on coloring process of a white bread have been studied under convective heating. The white bread was baked by the hot air impinging to the surface of the bread under an open condition. Experiments were performed for the wide variations of the air temperature, 100-400°C, and the air velocity, 1.7-15.0 m/s. The variations of the surface temperature and the surface color of the bread were measured with time. The coloring rate increased with the increase of the air temperature or with the increase of the air velocity. If the heating energy was fixed to a certain value, the coloring rate increased with the increase of the air temperature. If the air temperature was fixed to a certain value, the coloring rate increased with the increases of the total heat supply which was calculated from the heating energy and the baking time. The data of the surface color and the surface temperature showed that the surface color depended only on the surface temperature but not on the air temperature, the air velocity, and the baking time. It suggested that the coloring process of the food could be controlled by controlling the surface temperature which depended on the air conditions and baking time.

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γ-Aminobutyric acid (GABA), a hypotensive compound, is formed from glutamic acid by glutamate decarboxylase under anaerobic conditions in tea shoots. In the first three hours of anaerobic incubation, glutamate was remarkably decreased and GABA was considerably increased. But under continuous anaerobic incubation, those of amino acids remained almost constant. After three hours of anaerobic incubation, when tea leaves were placed under aerobic condition, glutamate increased rapidly up to its original amount. But GABA didn't decrease. After one hour of aerobic incubation, tea leaves were given three hours of anaerobic incubation again, and then accumulated glutamate changed to GABA. As a result of this treatment, the amount of formed GABA increased over 1.5 times more than that under usual continuous anaerobic incubation. By four times repetition, GABA in tea leaves was formed 2.3 times as much as that under usual anaerobic incubation in the third crop of tea. By this new method, the level of GABA in tea leaves of the third crop reached to the same level as tea leaves of the first crop treated by the previous method.

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A C₃₀ stationary phase high performance liquid chromatographic method was carried out for quantitative determination of β-cryptoxanthin in Satsuma mandarin juice. The studies indicated that β-cryptoxanthin underwent isomerization and degradation on a C30 column. The addition of a solvent modifier (ammonium acetate) to the mobile phase improved the recovery of β-cryptoxanthin from the column from ca. 83% to 99%. A thermostatically controlled column (27.5°C) demonstrated much better separation of geometric β-cryptoxanthin isomers. Using these methods, , β-cryptoxanthin content in Satsuma mandarin juice was found to be 1.01 mg/100g and the two minor peaks of cis-isomers were found on the chromatogram. These two peaks were tentatively identified as 13- and 13'-cis-geometric forms of β-cryptoxanthin.

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Inhibitory effects of the β-cryptoxanthin rich powder (CRP) on azoxymethane (AOM)-induced aberrant crypt foci (ACF), which are precursor lesions for colon carcinoma, were studied. CRP containing 0.67% β-cryptoxanthin was prepared from Satsuma mandarin (Citrus unshiu Marc.) juice. Male F 344 rats were given s.c. injections of AOM (20 mg/kg body wt) once a week for 2 weeks to induce ACF and they also received diets containing 0.5% CRP for 4 weeks. CRP feeding reduced the incidence of ACF by 20% after 4 weeks (P<0.01) and 18% after 11 weeks (P<0.005). In addition, the activities of glutathione S-transferase (GST) and quinone reductase (QR) in liver and colon of rats gavaged various doses of CRP (0, 40, 200 and 400 mg/kg body wt) for 5 days were assayed. CRP significantly increased the activities of GST and QR in the liver and colon. Suppression of ACF formation by CRP might relate to elevation in the phase II enzymes GST and QR of the liver and colon.

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It is reported that high correlations were observed between palatability of rice and water uptake ratio or total solids at 70°C. Studies on water uptake ratio and total solids around 70°C and estimation of total solids from iodine colorimetry were carried out to simplify an analysis of water uptake ratio and total solids at 70°C. (1) High correlations were recognized between total solids at 70°C and total solids at 68°C or 72°C. High correlations were also observed in total solids percentage. F values of water temperature were not significant at variance analyses of water uptake ratio percentage and total solids percentage. In a case that many samples prevent from maintaining water temperature, it is assumed that analytical error by water temperature was diminished in the analysis of total solids percentage. (2) A high correlation between total solids and absorbance of iodine colorimetry was observed. Difference between total solids estimated from absorbance and total solids was small. It is assumed that it was enable to shorten analytical time by estimation of total solids.

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A preliminary screening for deodorization activity was conducted for 20 different familiar wild grasses. The activity was assayed against methyl mercaptan dissolved in water by headspace gas chromatography. Among those showing significant activity included dandelion (Taraxacum spp.), prickly sow-thistle (Sonchus asper), thistle (Cirsium japonicum), low striped bamboo (Sasa veitchii), horse-tail (Equisetum arvense), and dokudami (Houttuynia cordata); their activity (%) were 97.5, 88.6, 90.2, 87.5, 93.7, and 98.3, respectively. Their deodorization property has not been hitherto reported except for dokudami.

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This study has been done to clarify whether dietary fiber and phosphorylated oligosaccharide can depress lipid peroxidation and maltase inactivation of rat small intestinal mucosa induced by 2, 2'-azobis (2-amidinopropane) dihydrochloride (AAPH), a generator of free radical in aqueous phase. Thiobarbituric acid reactive substances (TBARS) of small intestinal mucosa increased linearly by incubation with AAPH. Maltase activity decreased linearly by incubation with AAPH. The increase of TBARS and the decrease in maltase activity were not observed in the presence of fibers, such as cellulose, pectin, and alginate or phopsphorylated oligosaccharide (PO). Regardless of the incubation time with AAPH, apparent maltase activity was enhanced by the addition of dietary fibers and PO. It needs further investigation to make clear how fibers and PO protect maltase against the oxidative stress

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Antioxidative activity of constituents from ethyl acetate extract of bamboo shoots sheath was studied by the following procedures. The extracts were silica gel column chromatographed using the solvent system of hexaneethyl acetate-methanol and moreover, antioxidative fractions were purified by ODS-HPLC using the elution solvent system of HH₂O-methanol. Antioxidative activity of thus obtained fractions were examined by the POV method. As the results, two antioxidative constituents of I and II were isolated and identified as Tricin and Taxifolin for the first time, respectively. The antioxidative activities of I and II were about 10% and 1% of that of a-Tocopherol, respectively.

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We have developed a flow injection method to determine r-aminobutyric acid (GABA) which is known as the main component for suppression of blood pressure in GABA-enriched tea. The concentration of GABA was measured by the fluorescence of NADPH produced in an immobilized GABAse reactor. The interference originated from the fluorescence of tea components was diminished by acidifying the mobile phase and passing it through an ODS-minicolumn before fluorescent detection. The GABA content of GABA-enriched teas measured by this method highly correlated with that measured by the standard HPLC method.

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