It is well known that chlorogenic acid (Chl) reacts with amino acids to produce green pigments in alkaline pHs. In order to develop new natural pigments and understand the changes of color in food, we obtained the basic information for color reaction from the experiments done by combining Chl with glycine (Gly). We investigated the effect of pH on the green solution colored from Chl and Gly, which had the maximum at 680nm on the absorption spectrum. The solution changed its color at several pHs (2-9). Absorption spectra of the pH-treated samples were different among each other. These colors were pink, bluish purple, blue and green from acidic to alkaline pHs. Those spectra and colors were changed slowly by incubating. The pH-treated samples were also analyzed by reverse phase HPLC. The HPLC pattern of the samples indicated that the green solution colored in alkaline pH was composed of several reaction products.

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A determination method for off-flavor compounds in skim milk powder and the contribution of their contents to the organoleptic strength of the off-flavor have been investigated. Standard solutions of off-flavor compounds with various concentration were analyzed by single ion monitoring (SIM) method using gas chromatograph-mass spectrometer. Every plot of concentrations of off-flavor compounds vs ratios of their peak areas against that of internal standard gave straight line (r≥0.99) over a wide range. The odor concentrate isolated from commercially processed spray-dried skim milk obtained by simultaneous steam distillation-extraction under reduced pressure (SDE) was analyzed by present method. The reproducibilities (n=5) of every peak of off-flavor compounds were 4.8-5.7% as a relative standard deviation. Contents of off-flavor compounds in various skim milk powders which differ from each other in manufacturing lot were compared. The mean contents of tetradecanal, β-ionone and benzothiazole were 20, 0.13 and 0.40ppb for skim milk powders with normal flavor and 40, 0.62 and 0.80ppb for those with off-flavor, respectively. As a result of sensory evaluation of the skim milk powders by triangle difference test, the off-flavor was perceived when tetradecanal and β-ionone increased beyond 27 and 0.35ppb, respectively.

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Awa-bancha is a local tea in Japan, and is tasted by a few peoples in Tokushima and Kagawa prefectures. Harvested tea leaves are boiled for 10 minutes and are fermented with Nijiru for 7 to 10 days in a big tub. The Nijiru is a broth left by boiling fresh tea leaves. The details of microorganisms involving in the Awa-bancha fermentation are not investigated. Therefore we are especially interested in the microbial flora built on such environment as existing much amount of tannin, which are containing in tea leaves, and are known to inhibit the growth of microorganisms. We investigated microorganisms involving in the fermentation for 9 days in July, 1988. Lactobacillus plantarum and Klebsiella pneumoniae were dominant microorganisms involving in the fermentation. It was considered that they concerned the formation of the taste and the flavor of Awa-bancha.

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An investigation was conducted on how curdlan affects the rheological properties and gelling processes of meat gels under a model system using minced pork. Curdlan and proteins were added to the meat gels and their physical properties were evaluated by texture profile analysis, puncture test, and dynamic viscoelastic measurements. When curdlan was added to the meat gel instead of proteins, elasticity and breaking strain increased while the storage modulus decreased with an increase in the loss tangent, and these characteristics were responsible for differences in the texture of meat gels. To understand these differences, dynamic viscoelasticities of the meat were measured to see how curdlan functions during its gelling process. The results showed that, by the addition of curdlan, the storage modulus of the meat decreased and the loss tangent increased during heat treatment at approximately above 60°C. This indicates that during the heating process, curdlan absorbed and held free water within the meat gels, inc reasing the liquid component in the gels. Because of this function of curdlan, the texture and physical properties of the meat gel will be improved when curdlan is added instead of proteins.

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The changes in volatile flavor compounds and antioxidant activity of absorbed phenolic compounds in Katuo-bushi during smoking process were investigated. Results obtained were as follows: (1) The total phenol concentration in Katuo-bushi greatly increased for the first 10h smoking and reached maximum in the half period (15h) of smoking process. (2) The antioxidant activity of 40% ethanol extract of Katuo-bushi gradually increased during smoking and reached maximum in the half period of smoking process. The antioxidant effect seemed to be to phenolic compounds absorbed on Katuo-bushi during smoking. (3) The volatile compounds obtained from boiled bonito meat and Katuo-bushi during smoking process were analyzed by gas-liquid chromatography and gas chromatograph-mass spectrometry. Thirty-three compounds, including aldehydes, hydrocarbons, ketones and alcohols, were identified from boiled meat. The aldehydes were predominant compounds in boiled bonito meat and markedly decreased in first 8h smoking. No phenolic c mpounds were found in boiled bonito meat, whereas a variety of phenolic compounds were detected from Katuo-bushi. The phenolic compounds markedly increased in first 8h smoking and the amounts of most phenolic compounds were unchanged at all during prolonged smoking. In the advanced stage of smoking process, however, guaiacol, o-, m-, p- cresol and phenol increased in amount, and reached maximum concentration in middle stage of smoking process. Pyrazines were not detected from boiled bonito meat, whereas 6 pyrazine derivatives were found in Katuo-bushi. The pyrazine derivatives increased in number as well as in amount in the advanced stage of smoking process.

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Antimutagenicity on the Trp-P 2-induced mutagenicity to Salmonella typhimurium TA 98 of water extracts, ethanol extracts, and gummy materials prepared from four root crops, nagaimo (Chinese yam, Dioscorea opposita Thumb.), jinenjo (D. japonica Thunb.), satoimo (taro, Colocasia esculenta (L.) Schott) and processed taro (freeze dried "Poi") was examined. Each preparation showed its characteristic antimutagenic effect against the mutagenicity of Trp-P 2. Gummy material from processed taro showed the highest inhibition of 60% among the specimens used.

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Recently, much attention has been directed to problems of the environmental pollution. The present investigation was attempted to obtain a basic information about a possibility of the replacement of aluminium laminate film to plastic film which was more easy disposal treatment. Then, the effects on the stability of packed ground sesame seeds under ultraviolet light (UV) exposure (wavelength; 365nm), were compared among several packaging materials of different oxygen permeabilities and different 365nm UV absorbances. Against the oxidation of the sesame seed's oil, the plastic films cutting 365nm UV had a little protective function and the aluminium laminate film had the best one. On the protection of the roasted sesame aroma, the aluminium laminate film had also the best effect and the plastic films cutting 365nm UV had slightly the one. The plastic film with the permeability of 365nm UV brought the oxidative deterioration of the aroma. Volatile compounds growing from the clear plastic films under UV exposure, weaken the sesame aroma. So, the aluminium laminate film was the best packaging material.

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With the purpose of investigating the formula to predict the water activity (a_w) of "tsukudani", model "tsukudani" series were prepared with the major constituents; moisture, salt and total soluble sugar contents in "clam-tsukudani" (preserved foods boiled down in soy sauce and sugar). The a_w values in the model series were highly correlated to those in the "clam-tsukudani" with no statistic difference. The a_w in the model series increased logarithmically against moisture content, whereas it decreased linearly against salt and sugar contents. The dependence of a_w on the variable constituent amounts in the model series was formulated by multiple regression analysis. High correlation was recognized between the predicted and the measured a_w values in the model series. High correlation was also recognized between the a_w values calculated by derived equation and the measured values in the "clam-tsukudani", however the latter were apt to be a little higher than the former. The a_w values of 39 kinds of "tsukudani" and "sozai" in the market were predicted by use of the equation. High correlative relation was observed between the predicted and the measured values, but the latter was higher than the former as well as in the case of "clam-tsukudani". Therefore, numerical correction was introduced into the equation. The equation obtained in this experiment is able to be applied generally for such kinds of foods as "tsukudani" and "sozai".

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Flow properties of gelatinized modified starch suspensions were studied using a tube viscometer. The modified starches used were commercially available samples of hydroxypropylated distarch phosphate derived from waxy corn and potato starches (Starch A and Starch B). Two types of irreversible shear stress dependence of flow behavior were observed. By applying shear stress on the gelatinized starch suspensions, fluidity of Starch A (5.0wt%) decreased to an equilibrium value, while fluidity of Starch B (4.5wt%) increased. The equilibrium fluidities of Starch A depended on the intensity and frequency of the shear stress applied. On the other hand, the equilibrium value for the increase in fluidity of Starch B was not observed. Flow behavior observed under shear stress was not recovered, irrespective of the intensity of shear stress and/or standing period of time.

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Effects of seven kinds of vegetable extracts on the growth of eight human cell lines were measured by WST-1 assay, an alternative method to MTT assay. The green pepper extract showed strong inhibiting effect on the growth of almost of the cell lines. The cabbage extract showed promoting effect on the growth of K 562 cell line.

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A procedure for the determination of carbon monooxide (CO) in irradiated spice samples evolved by microwave heating with a CO sensor was developed. Samples (3-5g) placed in a sample vessel (150ml) was heated in a microwave oven for 1min, and the headspace gas was introduced into a CO sensor. The determination limit of CO gas was 0.1ppm using 3g of samples. Immediately after irradiation of black pepper and red pepper, dose response of CO concentration in these samples using the proposed method were clearly observed and well correlated with those of chemiluminescence method, gas-chromatographic method and electron spin resonance method. After storage for 3 months, however, dose response in irradiated samples could not be found because of loss of CO.

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Binding of decanoate to soybean β-conglycinin has been studied using physically and chemically modified β-conglycinin. The role of the native conformation and the cationic groups as the binding sites and the location on the amino acid sequence have been investigated. The native conformation with a quaternary structure showed the highest number of bound ligand. None of the modified β-conglycinins binds decanoate quite as firmly as the intact β-conglycinin molecule. Competitive binding studies demonstrated that the binding of methyl orange and fatty acid to β-conglycinin occurred at the same cationic sites. The association of carboxylate anions with β-conglycinin involves electrostatic attraction of the carboxylate anions to protein cationic sites that lied close by the NH²-terminal together with the hydrophobic interactions between the fatty acid hydrocarbon tail and the nonpolar side chains of the protein. Studies with reduced and non-reduced β-conglycinins have provided additional insight into the binding mechanism. The disulfide bond formed between subunits reduces the flexibility of the β-conglycinin molecule, especially around the NH2-terminal segment, producing marked changes in the fatty acid binding characteristics of β-conglycinin. The strong fatty acid binding sites may be located in the cleft between the α and α^' subunit contact regions.

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