Ten healthy adult males (20-25 years old) who ingested in sugar under 30g/day and drank no alcohol, were divided into two groups which were essentially the same in the age, body weight and height. During an experimental period of 10 days group 1 was fed unpolished rice and group 2 polished rice as staple food, and both groups were given 50g of sugar every day and 2, 520.2kcal/day as energy intake. Then the repressive effect of dietary fibers contained in unpolished rice was examined on an increase in serum level of cholesterol and triglyceride under these experimental conditions. The following results were obtained.
1) Serum total cholesterol was within a normal range in group 1 at 5 days of experiment and at the end of the experimental period. In group 2 it increased to 202.8 and 262.4mg/100ml (that is 1.4 and 1.8 times, respectively, as high as the pre-experimental level) at 5 and 10 days, respectively, of experiment.
2) The cholesterol which had increased particularly in level in the group of polished rice was proved to be total-cholesterol-HDL-cholesterol (LDL+VLDL+other lipoprotein-cholesterol), which was regarded as one of the important etiological factors of arteriosclerosis.
3) The serum triglyceride level at the end of the experiment was 112.4 mg/100ml (gain 14.2mg/100ml) in group 1 and 132.4mg/100ml (gain 21.6mg/100ml) in group 2. It was within a normal range in both groups. But in the group 2 it increased higher than that of group 1.
4) Accordingly, these experimental results showed to demonstrate the repressive effect of dietary fibers on an increase in level of serum cholesterol and triglyceride.

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Weanling male Wistar rats were fed diets low in protein (10% casein or soy bean), with or without iron supplement, which varied in the kind of starch (corn of tapioka) and their effects on the mineral balance were repeatedly determined.
When dietary iron level was low, soy bean protein enhanced the iron retention, hepatic iron concentration and hemoglobin value compared to casein protein, regardless of the kind of starch.
The kind of starch and dietary iron level might affect to the mineral balance. Corn starch showed the higher calcium retention than tapioka in the normal iron level. In the low dietary iron level, there was considerable difference in the phosphorus balance between two balance tests, while tapioka had no such change.
Corn starch with normal iron level enhanced the magnesium retention compared to tapioka.

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This experiment was carried out to investigate the effect of dietary protein levels on the recovery from iron deficient status in rats. Weanling male Sprague-Dawley strain rats were used. Anemic rats were made by feeding an iron poor diet for 6 weeks. Those anemic animals were divided into two groups, and 5% and 20% amino acid mixed diets were tested as recovery diets. Iron contents in two recovery diets were almost same (5% A.A. diet: 1.02mg%, 20% A.A. diet: 1.01mg%). The recovery process was observed as gains of hematocrit, hemoglobin concentration and red blood cells at weekly intervals during 3 weeks of recovery period. Also, the iron contents in the liver, spleen, bone marrow, muscle and cerebrum were also examined. The following results were obtained.
1) The rats showed markedly iron deficiency anemia by feeding an iron poor diet for 6 weeks.
2) The values of Ht, Hb and red blood cells in both recovery groups slowly increased by feeding each recovery diets. However, there were no significant difference of those values between low (5%) and high (20%) protein diets at 3 weeks.
3) The iron contents of various tissues in both recovery groups somewhat increased at the time of deficiency, but those contents were still lower than those of control group. The contents of all tissues were not significant difference between both recovery groups.
4) This experiment did not indicate effect of dietary protein levels on the regeneration of Ht, Hb, RBC and iron contents of the tissues in anemic rats, and was discussed in relation to growth, the status of deficiency, iron intake and other factor in the animals.

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Three experiments were performed to investigate the mechanism of urea utilization and the nutritional roles of intestinal flora on the utilization of urea by rats fed with a protein deficient diet. The results obtained were as follows;
1) Ammonia content in the small intestine in LPD (Low Protein Diet) group fed with a low protein diet for 2 or 5 weeks was about three of five times higher than that of control group fed with SPD (Standard Protein Diet) after administration of urea (0.2gN/100g B.W.). The increased ammonia in the small intestine by LPD group is presumably due to the increased urease activity in the intestine, because it is generally accepted that the intestinal urease is entirely microbial in origin.
2) The ¹⁵N incorporation into plasma protein of LPD group was significantly higher than that of the control group two hours after the administration of ¹⁵N-urea (10mg/100g B.W.) and a higher level of ¹⁵N concentration in plasma protein in LPD group was maintained thereafter. The ¹⁵N incorporation into the amino acids (Lys, EAA, NEAA) of plasma protein was higher in LPD group than in control group. EAA means the mixture of essential amino acids and NEAA means that of nonessential amino acids. The differences in incorporation rate of ¹⁵N between LPD and SPD group were significant (p<0.05) in case of EAA and NEAA.
3) The ¹⁵N incorporation into Lys, EAA and NEAA in portal plasma seemed to be higher in LPD group than in control group one hour after the administration of ¹⁵N-urea (10mg/100g B.W.). However, the ¹⁵N incorporation into each free amino acids was suppressed considerably by the administration of antibiotic mixture. It follows that amino acids may be synthesized from urea in the intestine by intestinal-bacterial action and absorbed from portal vein. Those amino acids may be incorporated into plasma protein as indicated in 2). From these results, it may be concluded that the ammonia nitrogen converted from urea by the action of intestinal-bacterial urease in the intestine is utilized for the synthesis of essential and nonessential amino acids in protein deficient rats and transfered to the liver through portal vein and utilized for protein synthesis. It is suggested that protein deficiency may change the population of intestinal bacteria so as to increase the urease activity. This change may be one of the adaptive responses to low protein diet to conserve nitrogen.

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“Uruka” is made mainly from salted viscera of sweet smelt (Plecoglossus altivelis, Temminck et Schlegel) and has a characteristic bitter taste. The raw material naturally contains gallbladders. In 1939, Ohta isolated taurocholic acid from gallbladder bile of this fish. Among various bile acids generally tasting more or less bitter, taurocholic acid is unique with its bitter taste with a somewhat sweet flavor. The present paper deals with the bitter components in “uruka” in relation to bile acids.
Total bile acid fraction was extracted from “uruka” and purified. Bile acids were analysed by thin-layer and gas chromatography and also by gas chromatography-mass spectrometry, and cholic acid as well as taurocholic acid was identified as main bile acid components. The concentration of cholic and taurocholic acid in “uruka” was 17.5 X 10^-4M and 5.5 X 10^-4M, respectively, as assayed by gas chromatography.
The senscry test on the bitter taste was performed with reference bile acids and the extract from “uruka. ” The values of the discriminative range, expressed as the concentration of total cholic acid (free and/or taurine-conjugated), were 8 X 10^-4M for cholate, 4 X 10^-4M for taurocholate, 4 X 10^-4M for cholate-taurocholate mixture (17.5: 5.5, molar ratio), and 8 X 10^-4M for the total bile acid fraction from “uruka, ” respectively. Thus the concentration of cholic acid and taurocholic acid in “uruka” was higher than the discriminative range of bitter taste for both bile acids.
When the bile acid fractions from “uruka” at different extraction steps were comparatively tested on the bitter taste, the bitterness increased in degree as the purification step progressed.
These results suggest that cholic acid and taurocholic acid constitute main part of the bitter components in “uruka. ”

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Glucosylsucrose (G₂F) and maltosylsucrose (G₃F) are principal constitutents of coupling sugar which is prepared from starch and sucrose. Coupling sugar has a similar taste to cane sugar and is used as a sugar substitute to reduce the incidence of dental caries in man. Streptococcus mutans produces a large amount of acids and insoluble glucan from sucrose so that it is considered to play an important role in the initiation of dental caries. However, resting cells grown in the medium containing glucose, sucrose, or maltose produced little amount of acid and no insoluble glucan from these sugar substitute. To clarify the mechanism of G₂F and G₃F metabolism in S. mutans strain GS 5, the cells were cultured in G₂F and G₃F.
When the cells were incubated in the presence of coupling sugar, G₂F or G₃F as a only carbon source, they adapted to these sugar substitute after a long time (72-100hr). The adapted cells produced a large amount of acid from G₂F as well as from glucose or sucrose but did not produce insoluble glucan. This is explained by the findings that growth in G₂F medium resulted in the induction of G₂F-phosphoenolpyruvate dependent phosphotransferace system and of maltase in the soluble fraction in these cells.

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Glucosylsucrose (G₂F) and maltosylsucrose (G₃F) are principal constituents of coupling sugar, which has a similar taste to cane sugar and is used as a sugar substitute in order to reduce the incidence of dental caries.
The toluene-treated cells of Streptococcus salivarius 13419 possesed cell-bound fructosyltransferase and produced a large amount of fructan with fructose and maltose but no glucose from G₂F. To clarify whether fructosyltransferase catalyzed this reaction, the extracellular fructosyltransferase was partially purified from Actinomyces viscosus Ny 1 and S. mutans JC 2. The enzyme obtained could produce fructan, fructose and maltose from G₂F. G₃F as a substrate of the enzyme was utilized to form fructan, fructose and maltotriose.
These results strongly suggest that a fructosyltransferase catalyzes the first step of metabolism of G₂F or G₃F. It is possible that G₂F and G₃F and utilized by an oral bacteria which has a fructosyltransferase. The high fermentative efficiency of G₂F and G₃F by S. salivarius among oral bacteria might be ascribed to high activity of a cell-bound fructosyltransferase.

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A carboxypeptidase (CPase) of black matpe seedlings which hydrolyzes carbobenzoxy-phenylalanylalanine (Z-Phe-Ala) was purified by means of ammonium sulfate fractionation (30-70%), Sephadex G-150 gel filtration, DEAE-Sepharose chromatography, 2nd Sephadex G-150 gel filtration, 2nd DEAESepharose chromatography and TOYOPEARL HW-50F gel filtration. The purified enzyme was found to be homogeneous by polyacrylamide gel electrophoresis. The molecular weight of this enzyme was estimated to be about 70, 000 by gel filtration.
The optima conditions for pH and temperature of the CPase were obtained at 6.0 and 50°C when measured with Z-Phe-Ala. The CPase activity was stable at pH 5-8 for 2hr standing at room temperature. The enzyme was inhibited by heavy metal ions (Hg⁺⁺, Ag⁺, Cu⁺⁺), DFP and PCMB, but not affected by EDTA, ICH₂COOH and 2-mercaptoethanol. As substrate specificity, Z-Phe-Ala was the most suitable substrate of those tested. The Km value for Z-Phe-Ala was 1.0mM at pH 6.0.

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Antimicrobial activity of trans-4-methylthio-3-butenyl isothiocyanate (TMBI) from Raphanus sativus L. cv. “Aokubi-Miyashige Daikon” was examined using Escherichia coli, Staphylococcus aureus, Saccharomyces cerevisiae, and Aspergillus oryzae. Isothiocyanate content of the sample used for the antimicrobial assay was determined in the form of thiourea derivative.
trans-4-Methylthio-3-butenyl thiourea (TMBT) was prepared from “Aokubi-Miyashige Daikon. ” Ethyl, allyl, butyl, or phenyl thiourea was prepared from each commercial isothiocyanate. Standard curves of these thioureas were made using modified Grote reagent.
Inhibitory effect of TMBI to microbial growth was detected and the value for minimum inhibitory concentration (MIC) was 2.14mM. However, TMBT did not prevent the growth of microorganisms. Moreover, antimicrobial activity of ethyl, allyl, butyl, or phenyl isothiocyanate was assayed and each value for MIC was obtained.
From these results, it was concluded that TMBI, prepared from “Aokubi-Miyashige Daikon, ” was the highest in antimicrobial activity among 5 kinds of isothiocyanates examined.

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We have been proposed the criteria for assessing cariogenic potential of foodstuffs. The criteria derived from four characteristics, i. e., Cariogenic Plaque Forming Ability and Acid Producing Ability as substrate utilized by cariogenic bacteria in the oral cavity, and Ingestion Time (IT) (acting time until swallowing) and Clearance Time (CT) (acting time after swallowing) as the intraoral acting time of substrate.
The purpose of this study was to determine intraoral acting times of foodstuffs as substrate. These are influenced by physical properties of foodstuffs. IT and CT were expressed as the times (sec) /intake volume (g) and adhesiveness of foodstuffs, respectively. Adhesiveness was determined by means of rheometer.
Results of this study agreed with values of food retention and clearance time in the oral cavity reported by Bibby, Lundqvist, and Konishi. Because of its simplicity and reproducibility, methods of this study were applicable for the evaluation of various foodstuffs including candy and chewing gum. Also this study suggested that IT may be determined by the chewiness of foodstuffs.

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Department of Food Science and Technology, Kyushu University School of Agriculture, Fukuoka Trans fatty acid contents of 15 margarines for home use, 33 margarines for institutional use, 5 margarines for school feeding, 26 shortenings for institutional use and human sera from healthy young adults were analyzed by gas-liquid chromatography. Almost all of Trans fatty acids found in the hydrogenated products were t-18: 1. Small amounts of c, t- or t, c-18: 2 were also presented and quite a few products contained t, t-18: 2. The average Trans fatty acid contents of margarines were 13.7% for home use, 12.2% for institutional use and 15.5% for school feeding. Shortenings for institutional use averaged 14.3%. The relatively low values for hydrogenated products for institutional use were attributed either to the severe hydrogenation or to the use of fats scanty of unsaturated fatty acids. Trans fatty acid contents of total lipids in sera from healthy graduate students who are taking meals mainly in an university refectory were estimated to be less than 1%. There was a slight difference in the content of Trans fatty acids among different lipid classes, and the highest value was observed in the free fatty acid fraction, mean value 3.1% (range 2-4%).

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Applicatian of the α, α′-dipyridyl method to the determination of total ascorbic acids in food is described. The extract of food with trichloroacetic acid was shaken with activated carbon to remove pigments. The filtrate was first neutralized and then dehydroascorbic acid was reduced to ascorbic acid by incubation with dithiothreitol. After removal of the excess dithiothreitol with N-ethyl-maleimide, ascorbic acid was determined by the α, α′-dipyridyl method. The values obtained by this on 54 different kinds of food were compared with the values obtained by the dinitrophenylhydrazine method. The present method was specific for ascorbic acid as the dinitrophenylhydrazine method in most of the foods, except fungi and black tea.

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