An investigation was done to clarify the cause of slimy spoilage of Tofu (soybean card). The viscosity of slimy water in a Tofu package which was enclosed with a small portion of slimy spoiled Tofu, increased after one day storage at 10°C or 15°C to reach the highest levels ranging from 2.8 to 3.0 centipoise after 2 or 3 days storage. Chemical analysis of the slimy water showed that polypeptides having molecular weights of 7.94×10² to 3.98×10³ seemed to be the viscous materials formed by microbial degradation of Tofu. From the slimy Tofu, Acinetobacter calcoaceticus was isolated as a causative bacterium. When soybean water-extract was inoculated with the bacterium, it was changed into the viscous solution during storage. (Received Aug. 16, 1983)

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Lipid and triacylglycerol compositions of total lipids in seeds of five cultivars of pumpkin ('Shintosa', 'Kinuta', 'Tokyo', 'Chikanarihoko' and 'Shirokikuza') were determined by combination of techniques of selective hydrolysis with pancreatic lipase, thin-layer chromatography and gas-liquid chromatography. Total lipid content of the pumpkin seeds ranged from 29.1% for 'Shirokikuza' to 37.4% for 'Shintosa'. Total lipids consisted of triacylglycerols (68.3-82.3%), diacylglycerols (2.5-8.7%), monoacylglycerols (1.0-2.9%), free fatty acids (6.2-10.3%), sterols (1.0-1.3%), sterol esters (0.6-1.0%) and compound lipids (4.0-7.3%). Total compound lipids had five fractions as follows: phosphatidylcholine (21.6-25.4%), monogalactosyldiacylglycerols and phosphatidylethanolamine (15.4-25.9%), phosphatidylinositol (16.0-23.2%), acylsterylglucoside, cerebroside and unknown material (11.5-24.0%)and phosphatidylserin and unknown material (16.4-18.9%). The major fatty acids in each lipid fraction were oleic (18.1-52.0%), linolic (22.6-49.6%), palmitic (8.7-36.2%) and stearic acids (3.8-10.5%). Triacylglycerol composition was calculated from the fatty acid compositions in the triacylglycerol fraction by selective hydrolysis with pancreatic lipase. Main triacylglycerols of pumpkin seed consisted of POO, OLP, OOO, OOL, OLO, LLP, LLL, LLPP, LOL and PLP (P: palmitic, O: oleic and L: linolic acid).

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The dough in which a portion of wheat flour was replaced by dietary fiber was prepared and the physical properties were examined. Dietary fibers used were commercial Cell R-80, Avicel RCN 81, and Fiber P-1. These fibers could contain 4.1 (Cell R-80)-4.8 (Fiber P-1) times their weight of water and 0.8 (Avicel RCN 81)-2.0 (Fiber P-1) times their weight of corn oil. In emulsifying activity and emulsion stability, there were no differences among the three fibers. The dough was prepared with either weak or strong wheat flour replaced by the dietary fiber (1.0-10.0%). Maximum consistency of the dough determined by the Brabender Farinography became higher as dietary fiber content increased when added water content was equivalent, regardless of the kind of dietary fiber. When dietary fiber content was equivalent, maximum consistency became lower as added water content increased. Regression equations were obtained between the consistency and the added water content. Steamed dough whose added water content was equalized to the dough with a consistency of 500 B.U. showed little difference in firmness measured by Texturometer for the various dietary fiber contents or types. Required content of water to obtain the consistency of 500 B.U. was different according to the kind of dietary fiber. As compared with the control, the water content in weak wheat flour dough should be increased by 11.5-14.4% and that in strong wheat flour dough should be increased by 10.0-19.5%. The steamed dough, 10% of which was replaced by Avicel RCN 81, was slightly preferred to the control by the sensory panelists. These results suggest the possible application of dietary fibers to the dough without inflation.

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General methods of detection or determination of gelatin in yogurt are the qualitative test of the AOAC and the determinative test of hydroxyproline. However, these methods are only qualitative or time consuming. The electrophoretic determination of gelatin in yogurt on cellulose acetate strips was studied as an easier method for direct detection and determination, and the following results were obtained. It was possible to determine the gelatin content accurately by the following procedure. After removal of casein from yogurt by isoelectric precipitation with sodium acetate solution, the filtrate was spotted on a cellulose acetate strip. Electrophoresis was conducted in 0.05M Na2B4 O7-NaOH buffer (pH 10) and stained by Coomassie Brilliant Blue R-250. After destaining and drying, the gelatin content was determined by densitometry at 550nm. It was able to distiguish between alkali processed gelatin and acid processed gelatin from their electrophoretic mobilities by this method. The recoveryies of gelatin added to yogurts were 80-110%. The calibration curve gave linearity in the range of 0.1-1.0% of gelatin in yogurt.

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What kinds of ligand bind to zinc in soybean seeds has been investigated by using various fractionation methods. Homogenate of whole grains of soybean was separated into three layers by ultra-centrifugation, and a DEAE-cellulose ion exchange chromatography was applied to the separated middle later. The fractions in which Zn has eluted were collected and used as the sample of the following examinations. Free amino acids contained in the sample before (a) and after (b) acidhydrolysis were identified with a Hitachi's amino acid analyzer. By comparison of the amino acid pattern of the sample (a) to that of (b), the presence of peptides bound to zinc was suggested. Chemical form of the Zn-peptide complexes was discussed. A DEAE-Sephadex A-25 column chromatography was applied to the sample (a) and the elution of Zn, P, sugars and nucleotides was examined. On the elution profiles, two peaks at which the four species has eluted together were observed. The eluted sugar was identified to be a pentose and it existed on a bound type but not on free state. The eluted nucleotides were consisted of different two compounds of which absorption maxima exhibited at about 250 and 275nm, respectively. Two types of Zn-nucleotide complexes were considered as the possible compounds consisted of the four species. Their chemical forms were discussed. On the basis of the findings and the results reported previously, extensively discussion on the status of Zn in soybean seeds was attempted.

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Gelatinization of azuki bean starch in the presence of azuki bean protein or some other proteins has been studied by measuring viscosity with the Brabender amylograph, to understand the gelatinization of starch in azuki Ann granules, which were prepared from azuki bean. The temperature of initial viscosity increment rised with increasing the amount of azuki bean protein added, the viscosity at 95°C decreased regardless of the amount of the protein added, and the viscosity after 10min at 95°C decreased slightly by adding 10% protein calculated on dry-starch basis, whereas it increased by adding 50% protein. The addition of 20% casein, gelatin, polypeptone or ovalbumin resulted in temperature rise of initial viscosity increment of azuki bean starch paste. Viscosities at 95°C and after 10min at 95°C decreased by adding casein, gelatin or polypeptone, while the viscosity increased by adding ovalbumin. The effects of azuki bean protein on gelatinization of potato, sweet potato, corn, and wheat starch were also examined. These results suggest that the swelling of azulci bean starch is suppressed at a wide range of temperature by adding relatively small amounts of azuki bean protein, and at low temperature ranges by adding large amounts of the protein, but it is promoted at high temperature ranges by adding large amounts of the protein.

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The free sugar contents in tea shoots grown under unshade or shade culture were compared between 1st crop ones (April and May) and 3rd crop ones (August). The difference of free sugar contents of various leaf presented in one tea shoot were also investigated. (1) Except the stachyose content in tea shoots grown under shade culture, the free sugar contents increased during development of tea shoots. The stachyose content hardly increased during development. (2) Under unshade culture, the degree of the increase of the free sugar contents during development of tea shoots was greater than that under shade culture. (3) The free sugar contents of tea shoots cropped at 1st crop differed little from those cropped at 3rd crop. (4) The free sugar contents were much in the leaves of lower position, and the proportion of the fructose content to the total of the free sugar contents in green stem was greater than in leaves.

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In previous papers, we have studied thermal diffusivity of spherical and slab solid foods, and the cooking-rate equations of slice and spherical root vegetables. In order to design various kinds of cooking apparatus, it is also necessary to measure thermal diffusivity of softish foods such as sol and gel. In this paper, we studied thermal diffusivity of sols and gels of egg yolk and white in a slab container. The values of thermal diffusivity were obtained to be 0.069 and 0.083 cmcm²/min for the gels of egg yolk and white, respectively. The reported numerical integral method for the unconstant conditions by using a non-linear least square method are useful to obtain the values of thermal diffusivity of various softish foods.

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Using plain-yoghurt instead of Sunki, the ohtaki-kabura and komatsu-na were pickled under sunki pickling-method. Various properties of those pickles were compared with those pickled similarly using Sunki from Kiso district, and following results were obtained: (1) Both the contents of crude protein in the pickles treated with plain-yoghurt and that of Sunki are rich compared with those in raw leaves according to the exudation of water soluble non protein matters in raw leaves. But the former is inferior a little to the latter. (2) In the case of ohtaki-kabura, the contents of free amino acids, sweet taste and tasty amino acids in the pickles treated with plain-yoghurt are larger to those in the pickles treated with Sunki, and the former is superior to the latter in sensory test. (3) The contents of the total amino acids of the pickles treated with plain-yoghurt and Sunki are larger to those in the raw leaves as similar case of crude protein. But the rate of increase in ohtakikabura in larger to that of komatsu-na. And the increasing-rate in the plain-yoghurt treated matter is larger a little to that in the Sunki treated matter.

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A simple and rapid method for the assay of caffeine in tea was developed by employing highperformance liquid chromatograph with UV detector. An assay solution was prepared as follows: 100mg of pluverized tea was extracted for 30min with hot water (80°C). The extract was filled up to 100ml and added 200mg of polyvinylpolypyrrolidone (PVPP) to remove the phenolics. A column (4.4×250mm) was pcked with ODS-SIL (reverse phase C18, particle size: 10μm) and eluted with MeOH-Water-AcOH (74:25:1) at a flow rate of 1.0ml/min. The caffeine content was detected at 272nm (AUFS: 0.08). From the peak height of UV monitor, a streight caliblation line was obtained in the range of the caffeine of 0.05-0.25μg. The correlation coefficient between the values obtained by the official method of Japan and those by HPLC method was 0.994.

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Investigation on compositional characterization of kecap was conducted. Kecap is a major seasoning or condiment in Indonesia which is made from fermented soybean. The commercial products are classified as 'common', 'sweet', 'salty' and 'viscous'. The composition of kecap varieties was characterized by their high sugar contents (40.51-65.45%) except the salty varieties (3.84-19.36%). The sugar contents were mostly sucrose, glucose and fructose and were derived from the sweetening agent added, i.e. palm sugar, cane sugar or molasses. Total nitrogen, formol nitrogen and free amino acids were much lower than those of Japanese soy sauce except one sample of salty kecap. Lower nitrogen contents indicate poor fermentation and excessive dilution of moromi with brine. Addition of large amounts of sugar could be another factor. Ash contents of sweet, common and viscous types of kecap were lower than those of Japanese soy sauce and were composed of minerals derived from soy beans etc. in addtion to sodium chloride. Lactic acid was the dominant organic acid present. However, some of the varieties were also rich in succinic, pyroglutamic or butyric acids.

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