Viscous Polysaccharides were extracted from three species of Yam, Jinenjo (Dioscorea japonica THUNB.), Tsukune-imo (D. opposita THUNB.), and KaU-09 (D. alata L.) which was introduced from South-East Asian district. These yam viscous polysaccharides (Y.V.P.) were finally purified through ion-exchange resins ater treatment with SDS-EtOH five times to remove proteinic and phosphorous impurities. Chemical and rheological properties of Y.V.P. were comparatively estimated and the following results were obtained. (1) Carbohydrate contents in the acid-hydrolysates were analysed to be 53-55%, and 90% of the resulting reducing sugars was mannose. The rest of sugars consisted of small amounts of arabinose, glucose and galactose, and a trace of xylose and rhamnose was also detected. Acetyl group was found to be about 2 moles per one sugar residue. There were little or no difference in sugar components among these three species of yam. (2) Protein contents of these Y.V.P. ranged from 2.0% to 2.2% and their amino acid compositions were almost similar to each other. The major amino acids were Asp., Glu., Ala., Ser. and Gly. (3) Viscosity of the Y.V.P. solutions which were treated with SDS and EtOH was almost similar to each other. Viscosity of the Y.V.P. solution increased remarkably after treatment through ion-exchange resins, and the increase was largest for KaU-09. Viscosity of finally purified Y.V.P. solution from KaU-09 was highest in water but lowest in 0.1M NaCl. Change of reduced viscosity against concentration in the purified Y.V.P. solution was larger in case of Jinenjo and Tsukune-imo than KaU-09, suggesting that interaction between Y.V.P. molecules was more strong in Jinenjo and Tsukune-imo than in KaU-09. These results show that rheological behavior of finally purified Y.V.P. from three species of yam was not equal.

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Cultivation test of sweet corn (cv. Golden Earlipak) was conducted to analyze the changes in chemical components including a flavor precursor of kernels (on the center 10cm of sweet corn cobs) during maturation in 1984 and 1985. S-methyl methionine sulfonium salt (S-MMS) which was known to be the precursor of dimethyl sulfide was detected during maturation. Dimethyl sulfide is recognized to be a key characteristic compound of flavor (Top note) of heated sweet corns. (1) The moisture content of kernels decreased quickly with maturation. The moisture content of kernels at the optimum stage of maturation for the purpose of processing to dried sweet corn powders was 70-74%. (2) The free-sugar and free-amino acid contents of kernels decreased rapidly with maturation. Meanwhile, the starch (starch and water soluble polysaccharides) content of kernels increased rapidly with maturation. The protein content of kernels was almost constant during maturation. (3) The solid matters of all kernels (on the center 10cm of sweet corn cobs) increased linearly with maturation. A large part of this increase resulted from the increasing of starch (starch and water soluble polysaccharides). (4) The S-MMS content of the kernels showed a logarithmical linear decrease with the days of maturation. The S-MMS content in the optimum mature kernels was 150-250μ mol/100g-dry matter basis. Also, it was very interesting that the maximum amount of S-MMS in all kernels was observed near the optimum stage of maturation. (5) To harvest sweet corn (cv. Golden Earlipak) with the best taste and flavor, it was very important to estimate the harvest time precisely and to harvest this crop just at the optimum stage of maturation.

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We have been focusing our research interests into application of ¹³C-NMR spectroscopy to facile classification and quality evaluation of foods. Various vinegar samples were subjected to ¹³C-NMR spectra measurements without any pretreatment at all. The spectrum of each Vinegar sample was characteristic. The spectra exhibited differences of materials and manufacturing processes of vinegar. Most of the prominent signals were assigned to known major vinegar components, but a few cider vinegar gave unassignable signals. Guided by the characteristic signals, 1, 3-propanediol and 2, 3-butanediol [a ca. 1:1 mixture of meso and DL-isomers (9:1)] were isolated as main constituents of the vinegar (ca. 0.1%). ¹³C-NMR Spectroscopic analysis was also found to be useful for facile quality control.

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Exuding behavior of soybean oligosaccharides by hot water were studied through TLC and HPLC. Exuding oligosaccharides increased as immersing temperature increased, and the exudate was chiefly made up of sucrose, raffinose and stachyose. The ratio of these oligosaccharides was almost constant above 50°C; sucrose: raffinose: stachyose (63:6:31). However, only small amounts of the oligosaccharides were obtained below 40°C. The extension of immersing time enabled to let out larger amounts of the oligosaccharides with almost constant ratios. The amount of oligosaccharides exuded from hypocotyls alone was about 1.8 times as large in the case of 80% ethanol extraction, and 2.5 times as large as from whole soybeans in the case of hot water immersion. Hot water exudate was extracted with methanol and was separated into soluble and insoluble fractions. Eighty-four % of oligosaccharides in the MeOH soluble fraction was sucrose and 86% was stachyose in the MeOH insoluble fraction. Thus, crude fractionation into sucrose and stachyose was found to be possible. The oligosaccharide contents of 24 kinds of soybeans, including saponin Aa types and Ab types, were investigated. The result showed that Ab type soybeans had higher oligosaccharide contents than Aa type. The average sucrose content of Ab type soybeans was 4% higher. However, no difference in constituent oligosaccharide ratios was observed between both types.

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The milling characteristics and the properties of milled rice of parboiled brown rice were investigated. The electric power consumption of parboiled brown rice using the abrasive type and friction type mill was higher than that of untreated brown rice. The electric power consumption by abrasive type mill increased with the increase of degree of gelatinization. When the degree of gelatinization was above 30%, the electric power consumption increased steeply. The electric power consumption by friction type mill decreased with the increase of the degree of gelatinization. However, the minimum value of parboiled rice was one and a half times as much as untreated brown rice. The temperature of milled parboiled rice was about 5°C higher compared with untreated materials. The broken kernel rate was higher when the degree of gelatinization was in range of 2-40%, while decreased when the degree was more than 50%. As the degree of gelatinization increased, the bulk density and whiteness decreased. The light transmittance, water absorption and color difference were increased due to increasing the degree of gelatinization.

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Potato samples (7mm diam. ×30mm length) were cooked in water at a temperature from 85 to 105°C with a cylindrical heating vessel in a constant temperature bath. Changes in a temperature at the center of the potato were measured with a CA thermocouple. The cooking process consisted of unsteady heating and cooling periods, and constant temperature cooking periods. Since the cooking of potato progressed during the unsteady thermal process, cooking time for it was corrected to the value of cooking time under constant temperature. Changes in hardness during cooking were measured as an index for cooking value. The hardness of potato was slightly increased (about 14% of initial value) in the initial stage of heating. Then potato softened with time. The softening process was divided into two stages of different mechanisms. The 2nd stage of softening followed with a time interval after the 1st stage. The interval decreased with the increase in cooking temperature. Hardness of the sample decreased to about 1/10 of the initial value at the end point of the 1st stage, irrespective of the cooking temperature. The softening behavior in both stages could be analysed with the pseudo-first order rate equation. The activation energies for the 1st and 2nd stages of softening were 171 and 123kJ/mol, respectively. Logarithmic values of the starting time, t, of the 2nd stage were correlated linearly with cooking temperature, T, and expressed as log t=8.85-6.33×10^-2T.

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Lactosucrose (O-β-D-Galp-(1→4)-O-α-D-Glcp-(1→2)-β-D-Frcf) was produced from the mixture of sucrose and lactose by Bacillus natto levansucrase [EC 2. 4. 1. 10]. The enzyme was purified by precipitation with ammonium sulfate and chromatographies on Butyl-Toyopearl 650M and DEAE-Toyopearl 650S. Molecular weight of the enzyme was estimated to be 55kDa in SDS-polyacrylamide gel electrophoresis, with its isoelectric point at pH 4.9. Optimum pH and temperature were 6.2 and 35°C, respectively. The enzyme was stable from pH 5.5-7.0 and up to 35°C. The activity was inhibited by metal ions such as Cu²⁺, Ag⁺, and Hg²⁺. The kinetics for lactosucrose formation was explained by the ping-pong mechanism with 0.21M for sucrose and 0.42M for lactose as Km values. In the immobilized enzyme, lactosucrose production was reduced, whereas levan production was promoted compared with those in the native enzyme.

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The storage method under a perfectly controlled atmosphere (PCA), in which not only O₂, CO₂ and relative humidity (RH) were controlled but also metabolic volatiles such as ethylene, acetaldehyde and others were automatically removed, was applied to mature-green mume fruit (Japanese apricot cv. Ohshuku). The fruits were stored under conditions of 2-3% O₂ and 3%, 8%, 13% and 18% CO₂ at 20°C and 100% RH, and the effects of environmental gases on the shelf-life were investigated and compared with seal-packaging method (using both linear low density polyethylene film with 30μm thickness and an ethylene-acetaldehyde removing agent). (1) C₂H₄ evolution was detected at the 19th day for seal-packaging and at the 15th, 19th, 23rd and 23rd day for PCA storage of 3%, 8%, 13% and 18% CO₂, respectively, while it was detected at the 3rd day in air. (2) Surface yellowing and flesh softening were delayed remarkably at higher CO₂ levels than at lower levels. (3) Pitting like injury occurred in the fruits stored in air, and internal browning which was caused by low O₂ (<2%) or high acetaldehyde (>90ppm) occurred in seal-packaged fruits. No injury was observed up to the 23rd day during PCA storage of 3-13% CO₂, while two types of CO₂ injury were caused at 18% CO₂. (4) Adding two days for distribution, the shelf-life were 12 days for seal-packaging and 15, 15, 19 and 12 days for PCA storage of 3%, 8%, 13% and 18% CO₂, respectively.

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In order to clarify the reason for soft texture of dried meat containing sugars, moisture content and shear force value of sliced pork as well as biochemical properties of myofibrillar proteins prepared from sliced pork such as Ca-ATPase activity and solubility in 0.6M KCl, 40mM Tris-HCl (pH 7.5) solution were measured during heat-drying of sliced pork with or without sugars. Plots of the logarithms of rate constants versus initial molarity of sugars provided liner relations for all indices employed. The slopes (denoted as e) of these linear plots were calculated using the following relation; e=(log k_Da-log k_D0)×1/a, where kDa and k_D0 are the rate constants for changes of indices in the absence and presence of a M of sugars. The "e value" was found to be highest for inactivation of Ca-ATPase of myofibril followed by a decrease of solubility of myofibril and lowest for the decrease of moisture content. Judged from "e value", it was strongly suggested that the added sugar during the heat-drying treatment of sliced pork effectively delayed the rate of denaturation of contractile proteins compared with that of the decrease of moisture content of sliced pork. In addition, the effect of sucrose was nearly two-fold higher than that of glucose for the change of indices employed. From these results, we assumed that the dried pork would be hard since the denaturation of contractile proteins would occur prior to the decrease in moisture of sliced pork during heat-drying treatment without sugar, and that, on the contrary, dried pork would be soft since the decrease in moisture of sliced pork would occur prior to the denaturation of contractile proteins during heat-drying treatment with sugar.

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Free amino acids (FAA) of commercial vanilla ice creams and their materials, dairy products and egg yolk, were determined by an amino acid analyzer. (1) The total FAA content of 11 samples of vanilla ice creams was from 94 to 338μg/g. Among FAA of ice creams, the major components were glutamic acid, taurine and phosphoethanolamine. (2) The ice creams were classified based on a price per volume into four groups; super premium type ice cream (SPI), premium type ice cream (PI), normal type ice cream (NI) and rakuto-aisu (RA) in order of price. The averages of total FAA of SPI, PI, NI and RA were 297, 191, 147 and 96μg/g. The difference in the composition of FAA between SPI and the other groups seemed to be caused by the use of egg yolk. (3) The total FAA contents of fresh cream, butter, evaporated skim milk, skim milk powder and egg yolk were 65, 42, 470, 1196 and 4697μg/g. The heat treatments on fresh cream, evaporated skim milk and skim milk powder during the process of manufacture were different, but their total FAA contents in micrograms per gram of non-fat milk solid were nearly the same. And also, their compositions of FAA were nearly the same. The compositions of FAA of ice creams except SPI were similer to those of dairy products.

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Crude actinidin was prepared from kiwifruits. Both myosin and actin were hydrolyzed by crude actinidin. The hydrolyzation of skeletal myosin molecule by crude actinidin was similar to that by chymotrypsin. Actinidin also hydrolyzed collagen molecule. When the beef pieces were immersed in the crude actinidin solution at 4°C, the cutting strength for raw and cooked meats reduced gradually with time of soaking and they reached to the constant after about 6 hours. The samples prepared from beef pieces immersed in the crude actinidin solution for 22 hours were observed by scanning electron microscopy. It was confirmed that the ultrastructure of the meats treated with actinidin was fragiler than that of control. AS the results, it is clear that actinidin which is contained in kiwifruits may be successful as meat tenderizer.

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Rakkyo-zuke is traditional pickles made from scallion (Allium bakeri Regel) in Japan, by seasoning with sugar and vinegar after desalting salted scallions which were preserved as raw materials. In order to improve the process, the changes in microflora and constituents during preservation of low-salted scallions and the qualities of Rakkyo-zuke made from these scallions were investigated. Fresh scallions were pickled in brines of 3%, 6% (low salt), 12% and 20% (high salt), and stored for 6 weeks at room temperature. In the brines of 12% or over, the growth of microbe was repressed and the changes of constituents were small during Preservation. In the lowsalted conditions, lactic acid bacteria and yeasts grew vigorously, and the viable cell counts reached to a level of 107 and 106 per ml after 4 weeks, respectively. The amount of lactic acid generated in the soaking fluid of 3% salted scallions was 0.4g per 100g, while it was 0.22g per 100g in the case of 6% salted. Though the quality of Rakkyozuke made from 3% salted scallions was inferior, that from 6% salted was equivalent to that from high-salted scallions. When 6 % salted scallions were used for raw materials, the time required for desalting them could be shortened at one tenth compared with the traditional manufacturing process.

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Effect of lemon juice on formation of N-nitrosomorpholine was investigated on a reaction of morpholine and sodium nitrite. Lemon juice concentrate was added to the mixture of morpholine and sodium nitrite and formation of N-nitrosomorpholine was determined by HPLC analysis. Inhibitory effect on the N-nitrosomorpholine formation was 26% (in air) and 36% (in air), 16% (in N₂) and 35% (in N₂), respectively, by the addition of original juice and 2-fold concentrated juice. Inhibitory effect on the Nnitrosomorpholine formation was 5% (2 mM, in air), 23% (5mM, in air), 57% (10 mM, in N₂) and 100% (20mM, in air), 22% (2mM, in N₂) 57% (5mM, in air) and 100% (10mM and 20mM, in N₂) by the addition of ascorbic acid. Inhibition of ascorbic acid in lemon juice on the nitrosation of morpholine was 7.4%. Therefore the presence of inhibitory factors other than ascorbic acid in the lemon juice was estimated.

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The changes in moisture, free-sugar and S-methyl methionine sulfonium salt (SMMS) contents of 'Mellogold' and 'Jubilee' kernels during maturation after silking were investigated. And the changes in S-MMS contents of 'Jubilee' kernels were also determined during storage after harvest.

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In order to improve tastes of soybean foods, enzymatic hydrolysis was investigated of soybean saponins as principal constituents possessing undesirable bitter and astringent tastes in soybeans. Microorganisms producing a soybean saponin hydrolyzing enzyme were screened by using 54 strains of Aspergillus niger. As a result, A. niger 7122 possessing the highest hydrolyzing activity among all strains was selected. The enzymatic hydrolysates from soybean saponins were examined with TLC and HPLC analyses. The soybean saponin A group was partially deacetylated at terminal sugar moieties of the sugar chain linked to C-22 of soyasapogenol A. Other soybean saponins are likely to be hydrolyzed at the glucuronide bond as a result of soyasapogenol B and E being detected in the hydrolysates. Also this result suggested that novel saponins with soyasapogenol E as aglycone might exist in the intact soybeans. The optimum pH for hydrolysis of Bb, a major saponin, was pH 5.0 to 5.5. The enzyme activity was stable at temperatures below 40°C and stable over the pH range of 4.0 to 6.0.

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Extrusion cooking of dehulled whole soybean, containing ca. 20% oil, was done through a twin-screw extruder equipped with a cooling nozzle. The effect of various parameters as barrel temperature, feed rate and screw speed on the textural quality of the extrudate was investigated and evaluated using the values of shearing force measured with the "blade shear cell" and "physical structure index" which was a modified version of Integrity Index of the FNS test. The concept of "orientation index" or the ratio of parallel to cross-sectional value of blade shear force was introduced, expressing the fiber orientation of extrudate which was strongly affected by the feed rate. The main factor affecting texturization of dehulled whole soybean was found to be barrel temperature, optimum at 160°C.

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Effects of food constituents, temperature and pH on near infrared spectroscopy for protein in aqueous solution in a transmittance mode were investigated. Bovine serum albumin was used as a model protein. Clear absorptions of the second derivative spectrum, which were due to protein, were observed at 1692, 1738, 1856, 2056, 2170 and 2286nm. Of these absorptions, the absorption at 2170nm was not significantly influenced in terms ofwavelength and absorption intensity even when salt, sugar, amino acid, oil and detergent were present, and even when pH and temperature were changed. These results suggest that a choice of the wavelength 2170nm is required to determine protein content with a high accuracy.

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To develop an effective utilization of milk casein, casein hydrolysate preparations of various average peptide lengths (APL) were prepared enzymatically with endo/exo-protease, and the stimulating effects on the qrowth of Streptococcus thermophilus by these hydrolysates were examined. The stimulating effects on S. thermophilus were compared among trial preparations and six kinds of commercial peptones. The results obtained were summarized as follows: (1) It was found that the hydrolysate preparation having APL of 1.5 showed the best stimulating effect on the growth of S. thermophilus among the samplesexamined. The free amino acid content of this preparation was about 50%. (2) It was presumed that the poor effect of domestic commercial peptones on the growth of S. thermophilus was due to their short APL and the lack of stimulating factors, such as vitamins. Therefore, it was concluded that the trial preparation having appropriate APL and sufficient vitamins content was the most suitable peptone for the cultivation of S. thermophilus.

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Waxy rice cake, a popular New Year food in Japan, is occasionally adulterated with waxy maize starch. The stable carbon isotope ratios (¹³C/¹²C) of 132 samples of 71 waxy rice cultivars grown in Japan and 54 samples of maize starch have been determined by isotope ratio mass spectrometry. The ¹³C/¹²C values of fully-milled waxy rice and maize starch ranged from -24.4 to -27.3 parts per thousand (per mil) and from -9.6 to -11.1 per mil, respectively. Rice cakes with δ¹³C values higher than -24.2 per mil, 3 standard deviations from the mean of fully-milled rice, should be considered adulterated.

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This paper reports the changes in the sugar of melons (Cucumis melo L.) in relation to invertase activity and also examines the properties of this enzyme in the three cultivars, 'Honey Dew', 'IW-57' and 'Ginsen'. The maximum invertase activity in the soluble fraction was observed at 20 days after anthesis for 'Honey Dew' and 'Ginsen', and at 40 days for 'IW-57'. The highest sucrose content of 'Honey Dew' and 'IW-37' was seen at 45 days after anthesis, whereas that of 'Ginsen' was at 40 days. The increase in sucrose contentcoincided with the period of the lowest invertase activity. However, the increase in invertase activity was not accompanied with the changes of reducing sugar content.

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