The effects of mixing rates (60, 150, 250, 350rpm) and the cooking times (15, 25, 35, 45min) on the physical properties of gomatofu (sesame tofu) were studied by using a rheometer and a scanning electron microscope (SEM). Gomatofu was prepared using two different kinds of cooking methods: the usual system A (simmering) and B (hot-water-dropping into cookpot to hold a constant quantity during cooking) were employed. A creep curve for the gomatofu could be analyzed by using a 4-element model. Hardness and elasticity of Hookean and Voigt body (E₀, E₁) of the (A) sample cooked for 25min decreased with mixing time for all of the samples under various mixing rates, and after 25min of cooking increased with cooking time because of weight loss. Adhesiveness and viscosity of the Newtonian and the Voigt bodies (η_N, η₁) of the sample mixed at 60rpm increased with cooking time, while both of the samples mixed at 250rpm and 350rpm decreased with cooking time. Hardness, adhesiveness and gumminess of the (B) sample for all mixing rates decreased exponentially with an increase of cooking time, but cohesiveness did not change in all of the cooking times. Adhesiveness showed different changes among mixing rates. SEM observations revealed that the sample cooked with a mixing rate of 60rpm for 15min did not have a honeycomb structure, while the sample cooked with the mixing rate of 250rpm for 25min had uniform-sized cells and a honeycomb structure. It is assumed that gomatofu is a phase separated model which has networks consisting of Kuzu starch and sesame protein.

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Dynamic viscoelasticity of cooked rice was measured by using a viscoelastometer with the double-side shear mode. Sensory evaluation tests were also carried out on the same samples. Fifteen varieties of non-glutinous rice, which were produced in the research project named "Development of Improved Rice Cultivars with Superior Grain Qualities" in these two years, were examined. In this study, correlation coefficients among three sensory scores related to texture (hardness, stickiness, and smoothness) and three parameters of dynamic viscoelasticity (dynamic modulus [G'], dynamic loss [G"], and loss tangent [tanδ]) were investigated. From the viewpoint of sensory evaluation to dynamic viscoelasticity, the highest correlation was observed between stickiness and tanδ with a correlation coefficient of 0.855. The second highest correlation coefficient was 0.817 between hardness and G'. G", however, had no significant relationship with any sensory scores. On the other hand, among the parameters of dynamic viscoelasticity, there were correlation coefficients of 0.728 between G' and G", and -0.708 between G' and tanδ. These results show that dynamic viscoelasticity, especially tanδ, is available as an instrumental index of stickiness, which is the most preferable texture of cooked rice for the Japanese.

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The objective of our study was to investigate the effect of preheating at high temperature under vacuum (preheating) on heat aggregation of whey protein isolate (WPI). A time course of turbidity was measured by heating at 2°C/min from 30 to 95°C. While the turbidity of a control WPI solution at pH 6.0 was increased from 53°C, the turbidity of preheated (120°C, 1hr) WPI was increased from 50°C. The peak temperature of preheated WPI was decreased from 65 to 57°C. SDS-PAGE showed that new high molecular weight components were formed after preheating (120°C, 3hr), and β-lactoglobulin was more sensitive to preheating than α-lactalbumin. The thermal behavior of preheated WPI was studied by differential scanning calorimetry (DSC). The peak temperature of maximum heat absorption of WPI was shifted from 72.5 to 74.2°C by preheating (120°C, 1hr). The denaturation enthalpy of preheated WPI was 50% lower than that of the control, These results reveal that preheating causes the conformational changes of proteins of WPI. The turbidity of the control WPI solution at pH 6.0 in the presence of 200mM NaCl was increased from 73°C, The turbidity of preheated (120°C, 1hr) WPI in the presence of 200mM NaCl was increased from 60°C. The temperature of aggregation of preheated WPI in the presence of 200mM NaCl was lowered by the addition of 5mM CaCl₂. These results suggested that desirable coagulation of preheated WPI were formed by addition of NaCl and CaCl₂.

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In this study we investigated the effect of preheating at high temperature under vacuum (preheating) on physical properties of heat-induced whey protein isolate (WPI) gels. Weak gels of preheated WPI (120°C for 1hr) was obtained at low heating temperature (70°C). Strong gels with high elastic modulus were formed when preheated WPI was heated at 90 or 100°C. The transition of flow behaviour of preheated WPI solution from rheopexy to thixotropy suggested that a precursor of gelation accompanied by reduction of activation energy required for gelation occured in the pre- heated WPI. The changes in molecular shape and surface charge of protein molecules associated with conformational changes in preheated WPI were obServed by HPLC analyses. β-Lactoglobulin structure was markedly influenced by preheating of WPI.

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Our objective was to examine the role of Ca²⁺ on heat aggregation of whey protein isolate (WPI). Ca²⁺ content of WPI was determined with an Atomic Absorption Spectrophotometer. A 10% WPI solution contained 3.01mM Ca²⁺ Dialysis removed 1mM free Ca²⁺ from the solution. When 50mM Ca²⁺ was added to the WPI solution (10%) followed by dialysis against distilled water, 10.15mM Ca²⁺ bound to WPI. When a 2% WPI Solutions was heated at 80°C for 30min with 5mM Ca²⁺, 1.27mM Ca²⁺ bound to the precipitate of WPI after centrifugation at 80000×g for 30min. A time courSe of turbidity of the WPI solution was measured by heating 3°C/min from 30 to 95°C. Dialysis had no significant effect on heat aggregation of the WPI solution (1%). Aggregation of WPI was increased slightly by the addition of 1mM Ca²⁺ The temperature of heat aggregation of WPI solution lowered markedly in the presence of 5mM Ca²⁺ Turbidity measurements performed during dialysis experiment of WPI confirm that direct Ca²⁺ binding to WPI contributes to the heat aggregation of WPI. Addition of 2mM dithiothreitol (DTT) lowered the temperature of heat aggregation of non-dialyzed and dialyzed WPI solution. These results suggest that both bound and free Ca²⁺ in WPI affect the heat aggregation, and the conformational changes of WPI molecules in the presence of DTT enhance the effect of Ca²⁺ on heat aggregation of WPI.

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From a point of view of quality evaluation of natural food color, the yellow pigments were isolated from the full matured fruits of Gardenia (Gardenia jasminoides Ellis) and identified mainly by LC-MS and ¹H-NMR. In addition, the changes in the content and composition of crocetin derivatives in fruits were examined at the seven stages from anthesis to full maturity in order to obtain the information regarding to the biosynthetic pathway of crocin. The results obtained could be summarized as follows: (1) The full matured gardenia fruits contained seven yellow pigments which were crocetin derivatives. The structures and composition [%] were as given below. trans-crocetin-digentiobioside (crocin) [71.6%], trans-cocetin-monogentiobioside-monoglucoside ester [5.8%], trans-crocetin-monogentiobioside ester [2.0%], cis-crocetin-monogentiobioside ester [4.2%], trans-crocetin-diglucoside ester [10.8%], trans-crocetin-monoglucoside ester [3.0%], cis-crocetinmonoglucoside ester [0.4%], (2) Gardenia fruits contained very small amounts of carotenoids at the enlargement stage but accumulated considerably crocetin derivatives in the process of maturity. The contents of total crocetin derivatives in full matured fruits went up to approximately 4.5mg/g (dry weight). The time course of changes in composition of seven crocetin derivatives in the maturing stage suggested that gentiobiose ester of crocetin was biosynthesized stepwise by binding glucose to crocetin glucose ester.

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Gardenia yellow pigment, which contains seven crocetin derivatives, is widely used to many process foods as food colorant. In this paper, the food chemical properties of the individual crocetin derivatives were examined on color tone, antioxidative activity, heat and light stability. The results obtained could be summarized as follows: (1) There was little difference in the chroma and brightness among the seven crocetin derivatives. In color tone (hue), however, there was clear difference depending on the number of glucose unit linked to crocetin. Thus the hue value decreased according to the increase in the number of glucose unit linked to crocetin, indicating that the color tone changes to reddish from yellowish tone. (2) All of crocetin derivatives inhibited oxidation of linoleic acid about 80%. This result showed that Gardenia yellow pigment was useful to prevent the oxidation of the process foods. (3) All of crocetin derivatives were stable for heat and residual ratio of pigment was more than 85% after the heat treatment of 80°C, 120 minutes. (4) All of crocetin derivatives were appreciably stable to irradiation of light with wavelengths in the range from 400nm to 700nm, but were extremely unstable to ultraviolet rays irradiation in the region from 250 to 390nm. Further, the stability of irradiation of crocctin derivatives which linked gentiobiose to crocetin were superior to others.

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We examined the mutagenicity of the extract of transgenic tomato by Ames test, to assess the safety of a transgenic tomato that had been established by gene transfection of a gene coding the coat protein of TMV. Juice and ethanol extract prepared from transgenic tomato showed no detectable mutagenicity on Salmonella typhimurium TA98 and TA100 with or without S-9 mix. Furthermore, extracts from six kinds of commercial tomato also did not show any mutagenicity.

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The method was developed to perform principal component analysis (PCA) using widely used NECTM PC on near infrared spectra taken by IBMTM PC. As the application of this method, wheat flours with different processing qualities were classified. Four kinds of commercially available wheat flours such as bread making four, Chinese noodle making flour, Japanese noodle making flour, and confectionery making flour were analyzed. The NIR spectra of 18 samples were recorded from 1100 to 2500nm and the dd² log(1/R) at several informative wavelengths were selected as variables for PCA. Principal components were calculated using the 11 dd² log(1/R) values at the wavelengths where standard deviation of dd² log(1/R) were large and downward peaks of dd² log(1/R) were observed. On the plane with axes of the first and the third principal components, four kinds of wheat flours were clearly classified. On examination of the eigenvector of the first and the third principal components, and the chemical constituents and physical properties of samples, it can be thought that the first principal component relates to sample particle sizes, and the third one relates starch contents, . As a result, it can be concluded that near infrared spectroscopy has a possibility to classify wheat flours with different processing qualities using PCA.

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It has been reported that flavonoids and limonoids of citrus fruits are excellent physiologically active compounds. In this study, an efficient method for recovery of flavonoids and limonoids from buntan peel (glazed albedo of pummelo fruit (Citrus grandis Osbeck))-boiled water (BPBW) was examined. Flavonoids from BPBW were crystallized by cooling at 2°C and separated. Recovery and purification of limonoids were carried out by HP-20 (φ50×500mm), XAD-2 (φ50×500mm) and silica gel C-300 (φ30×500mm) column chromatographies, and a stepwise elution from the column were carried out by using methanol and CH₂Cl₂-ethyl acetate (9:1→100% ethyl acetate) system, respectively. The yield of flavonoids (Fraction I) obtained from 1.0l of BPBW was 1.57g, which contained 97.9% of naringin without other flavonoids. Limonoids (Fraction III) obtained from BPBW contained deoxylimonin, ichangin, deacetylnomilin, limonin, nomilin and obacunone. The total limonoid concentration was 66ppm, which mainly consisted of limonin, nomilin and ichangin. Seventy-five point five percent of total limonoid in the BPBW were recovered. Recovery ratios of nomilin and limonin were 88.6 and 68.8%, respectively.

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Sixteen kg of unpasteurized filtered whole egg was frozen in a tin at -5°--20°C, and difference in quality between the outside and the center parts of the frozen egg mass was evaluated. Also 100g of whole egg was rapidly frozen at -60--20°C to clarify relationship between congealing temperature and aggregation of lipoproteins. The solid content of tinned frozen egg was less in the outside than in the center, and the difference was most evident in egg mass frozen at -5°C. In egg mass, frozen at -5°C or -8°C, apparent viscosity was higher in the center than in the outside, while reverse tendency for the variance of viscosity was observed in egg mass frozen at -20°C. The variance might be not due to the difference in solid content between the center and the outside. Difference in foaming properties between the outside and the center was not obvious. In gel-filtration of Soluble proteins of egg magma frozen at -8°C, there was a difference in the profiles of aggregated lipoproteins between the outside and the center, and their profiles were also different from those of egg magma frozen at -5°C or -20°C. When whole egg was rapidly frozen at -6°--20°C, an increase of viscosity and aggregation of lipoproteins emerged in one day in egg magma frozen below -12°C, while these changes were not observed in egg magma frozen at -8°C or -6°C and storaged for 5 days.

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This study was conducted to determine the effect of storage on the properties of potato starch. Starch was prepared from three varieties of potato, namely; Benimaru, Toyoshiro and Konafubuki, after storage at 5°C for 6 months. The average granule size, phosphorus content, Brabender peak viscosity and breakdown of the starches from the stored tubers for each variety were lower than those from the unstored tubers. The initial pasting temperature did not have a considerable change. The temperature at peak viscosity of Benimaru starch increased, while it decreased for both Toyoshiro and Konafubuki starches after storage. The viscosity and rigidity of 1% starch pastes also decreased during storage while the blue value increased. The decrease in Brabender peak viscosity and breakdown were closely correlated with phosphorus content (r=0.96^** and 0.93^**, respectively).

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Relationship between content of such polyphenols as chlorogenic acid, (-)-epicatechin, and (+)-catechin, polyphenol oxidase (PPO) activity, and browning in five cultivars of apples 'Fuji', 'Kogyoku (Jonathan)', 'Jona Gold', 'Mutsu', and 'Tsugaru' on the market was examined. Polyphenol was determined by high-performance liquid chromatography. Chlorogenic acid was found to be the major polyphenol (3-25mg/100g fruit). Chlorogenic acid and catechins rapidly decreased by browning. Catechins contributed to browning more than chlorogenic acid. PPO activity was measured using chlorogenic acid or (+)-catechin as the substrate. Cultivar Tsugaru contained polyphenols the least and turned brown the least among five cultivars, while it kept high PPO activity. Cultivar Mutsu showed the highest polyphenol content, the highest PPO activity and the most intense browning. The polyphenol content showed correlation with the browning.

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Meat species discrimination was examined on heat processed meat products by the analysis of histidine dipeptides, carnosine, anserine, and balenine, using high-performance liquid chromatography. The distribution of these dipeptides and their ratios, carnosine/anserine and balenine/anserine, were specific to each meat species of beef, pork, horse, deer, chicken, and turkey. Products made from single meat species of beef, pork, or chicken were almost always correctly identified from the dipeptide ratios. This discrimination technique was unaffected by the contents of moisture, fat, and/or other ingredients. The meat proportion in most of the mixed meat products made from any two meat species of beef, pork, and chicken was able to be semi-quantitatively determined using the standard curves of dipeptide ratio versus meat proportion.

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The suppressive effects on SOS response of Salmonella typhimurium TA 1535/pSK 1002 induced by MNNG and Trp-P-1 of the methanol extracts prepared from soybeans and soy products were investigated. The content of isoflavones in the extract was also determined. The extracts of soybean and soymilk scarcely suppressed SOS response by mutagens. The suppression by the extracts of fermented product was stronger than that by the unfermented products. However, the percentage suppression in the extracts of natto and soy sauce was similar to that in the unfermented products. The extracts of tempeh and miso having strong suppression contained much daidzein and genistein. On the other hand, the extracts of unfermented product and such fermented product as natto and soy sauce having weak suppression contained much isoflavone glycoside. The percentage suppression of the extracts from soymilks fermented by a strain of Lactobacillus bulgaricus or Streptococcus thermophilus was lower than that by a strain of Bifidobacterium longum or a mixture of three strains.

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The gelatinization property of etherified tapioca starch was investigated using a DSC, a photomicrograph and a Brabender Viskograph. The effects of the stabilizers (gelatin, locust bean gum, xanthan gum, carrageenan, guar gum, low methoxyl pectin and tamarind gum) on Viskogram of etherified tapioca starch was also studied. The results showed that addition of a stabilizer influenced the Viskogram of the starch. Guar gum or locust bean gum raised the viscosity of the starch after the temperature reached 95°C. All other stabilizers decreased the viscosity. Moreover all the stabilizers except guar gum raised the temperature at which the viscosity initially increased. Stabilizers with a high water-binding or gelling property were expected to suppress the degree of gelatinization. The investigation on the interaction between gelatin and etherified tapioca starch showed that gelatin promoted gelatinization at lower starch level while gelatin suppressed gelatinization at higher starch level.

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