Supernatant of coagulated soymilk on Tofu processing, termed Yu, is main waste water of Tofu factories. The recovery of proteins from the waste Yu is expected to be effective for reduction of waste water facilities and the recovered proteins should be utilized as food materials. A Yu preparation recovered from waste Yu water at a Tofu factory contmaterials. A Yu preparation recovered from waste Yu water at a Tofu factory contabout 60% of proteins as solid. The Yu proteins were rich in polar amino acids, especially, lysine, S-containing amino acids and threonine as essential amino acids when compared with Tofu and Okara, and the amino acid score was 61. From the feeding experimen ts ofrats, digestibility, net protein utilization and biological value of Yu proteins were 86.0, 44.5 and 51.7, respectively, but the protein efficiency was negative value, -1.70. The refore, it isclear that nitrogen metabolism of rats fed the Yu fraction was normal and the Yu fraction is suggested to contain some factors which effect on the growth of rats.

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A red pigment fraction was extracted from the mycelia of an actinomycete, Strept omyces californicus JCM 6910, derived from soil. The fraction was purified by column ch romato-graphies on silica gel and Sephadex LH-20 and was finally purified by reversed p hase HPLC. The purified pigment was identified as a new compound by the analyses of NMR spe ctra and named as dideoxygriseorhodin C. The pigment-peptide complex has potential use as a natural food coloring agent because of its water-solubility. The color tone in a queous solution on pigment-peptide complex showed from red to orangish-red (pH3-5) and showed purplish-red(pH6-9). Its fading was not observed by heating but its colo r tone was affected by sunlight. A red pigment, dideoxygriseorhodin C, was suggested to be safe in the biological tests of acute toxicity and mutagenicity. (Received Feb.17, 1989)

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Three kinds of Sunki pickles, with and without addition of Zumi fruits, collected from Kiso district were examined for their free amino acid contents, organic acids and volatile flavour components. A sensory test was also conducted. (1) The savoriness of the Sunki pickles depends not only on the free amino acid content but also on organic acids and the flavour. (2) A small amount of malic acid was detected from the Sunki pickles with Zumi fruits. (3) Addition of Zumi fruits to Sunki pickles activated the proliferation of lactic acid bacteria. (4) Forty-six kinds of volatile flavour components were detected from the Sunki pickles. From 13.7mg to 41.1mg of the volatile flavour components were contained in the Sunki pickles. In the sensory test, high evaluations were given to Sunki pickles with Zumi fruits which contained larger amounts of flavour components.

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A high-performance liquid chromatography using post column reaction system was established for the determination of polyphosphates (PP) in foods. After extraction of PP with ice-cold 4% trichloroacetic acid, the necessary sample pretreatment prior to HPLC analysis was only centrifugation of the extract at 30000g for 20min and filtration of the supernatant. Linear PP with the range of polymerization from 2 to 12 (P2-P12) could be separated on an anion exchange column, Protein Pak G-DEAE (Waters Co.), with 0.01M HNO₃ containing a linear gradient of NaNO₃ concentration as a mobile phase. PP were detected as the decrease of absorbance at 500nm of ferric-sulfosalicylate complex by means of an on-line post column reaction with 0.5mM FeCl₃ solution containing 2.5mM sulfosalicylic acid at room temperature. Recoveries of P 2, P 3 or P 4 from both cheese and kamaboko were 100.2, 98.0 or 95.0 and 98.0, 93.0 or 90.0%, respectively. The proposed method was applied to the analysis of commercially available food products. P 2-P 9 (total 5.64-14.679/kg) were found in various brands of processed cheese and P 2-P 3 (0.07-3.099/kg) in those of kamaboko, chikuwa, ham and sausage.

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Ultrafiltration of sweet-sorghum juice by polymer membranes and self-rejection type of dynamic membranes on ceramic supports was investigated. The permeate flux increased linearly with temperature from 20°C to 60°C without any influence of solute passage. Brown pigments produced by heating were almost rejected by the membranes. The suitable conditions of ultrafiltation were 0.2MPa pressure and flow velocity of more than 1.0m·s^-1. Little difference of the solute passage was observed between TOTO ceramic and GR polymer membranes in the experiment of volume reduction. The permeate flux with GR polymer membranes was initially about two times as much as that with TOTO ceramic membranes, however both fluxes were almost equal at RF7.

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Self-rejection type of dynamic ultrafiltration membranes formed on three different kinds of inorganic supports and polymer ultrafiltration membranes made by three different kinds of materials were applied to cross-flow filtration of sediment from pasteurized soy sauce.The effects of temperature, pressure, flow rate and pore size of ceramic supports on the permeate flux and rejection were investigated. The ceramic supports with pore size smaller than O.5μm were more suitable for filtration of pasteurized soy sauce than those with poresize larger than 1.0μm. Little difference of the permeate flux was observed among the three different inorganic supports (TOTO, MEMBRALOX and CARBOSEP). The permeate flux of the dynamic membranes were 30-50% of that of the polymer membrane (PM10). Dynamic membranes formed on TOTO ceramic supports showed a stable permeate flux during volumereduction operation, and 98%of pasteurized soy sauce was recorvered as a permeate.

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The effects of α-andδ-tocopherol (toc) on deterioration of cookies blended of carrot or spinach were investigated. The stability was evaluated on the basis of changes in peroxide value (PV) of the lipid fraction, color flavor and the levels of β-carotene and chlorophylls after baking and storage at 40°C. PV of the carrot-blended cookie was very low after baking and storage for 8 months. Whereas, PV of the spinach-blended cookie was about 12 just after baking and rapidly rose during 5 month storage. The addition of δ-Toc to cookie dough was effective to prevent deterioration of the cookies blended of carrot or spinach. However, addition of α-Toc resulted in a remarkable increase in PV of both types of cookies. The loss of β-carotene in the cookies blended of carrot or spinach during baking and storage was inhibited by the addition ofδ-Toc, but accelerated by that of α-Toc. Such effects were also observed in the case of chlorophylls in the cookie blended of spinach. Color and flavor of the cookies blended of carrot or spinach were deteriorated during storage. However, the deteriorations were inhibited by addition of δ-Toc, but promoted by that of α-toc.

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A frozen thin section of commercially available process cheese was prepared and transferred into an analytical transmission electron microscope by using a cryotransfer holder. The frozen thin section was then observed and X-ray microanalyzed. And also, it was compared with an Epon-em-bedded thin section. As a result, in the frozen thin section, especially large contents of P and Ca were detected from granules (0.2-1μm dia.), and Na, P, S, Cl, K, Ca were detected from smaller granules (20nm dia.). In the Epon-embedded thin section, however, these granules were not observed. It seems that the frozen thin sectioning method is effective for observing the inner structures of the native state of cheese and for carrying out X-ray microanalysis.

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Chinese yams were harvested in the middle of November in 1986 and were ground immediately after harvesting. The mucilage of the ground solution was purified by using sodium dodecylsulfate (SDS). Chemical composition was determined for the purified mucilage. Moreover, viscosity of the purified mucilage was evaluated using a rotationary viscometer. The results obtained were as follows: (1) Mucilage of the Chinese yams could be purified by using SDS. The protein was removed gradually from the mucilage without lowering the viscosity. (2) The purified mucilage contained 40% polysaccharide, 2% protein, 24% ash and 3% phosphorus. (3) The polysaccharide fraction of the purified mucilage consisted of mannose 80% and small amounts of fructose, galactose, xylose and glucose. (4) The viscosity of thepurified mucilage increased with a decrease in the mucilage concentration showing typical behavior of an electrolytic polymer. Furthermore, the intrinsic viscosity value for the purified mucilage was estimated to be 400.

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Dehydration rates of fish flesh by expression were analyzed under various conditions in detail in a previous paper. The results were inconvenient for practical use, because the rate constants were strongly dependent on pressure. However, the apparent rates were almost independent of it. In this study, a simple correlation without parameters related to pressure were derived and compared with the dehydration of slurry. As a result, ratios of the sample weight at any time to its initial were correlated well with a parameter, (time/initial weight²)^1/4 independently against pressure. And they were adequately approximated by a straight line within practical use.

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A flow injection analytical (FIA) system equipped with an automatic filtration unit was developed for the estimation of proteolytic activity of proteases for casein protein. Enzyme reaction for the protein digestion and the addition of trichloroacetic acid were performed by batch procedure prior to inject the digests into the flow system. Hammarsten-casein was used as a substrate of proteases and the resulting Folin-positive digests (trichloroacetic acid soluble digests) were filtered automatically and injected to the flow system, and then the digests were detected spectrophotometrically by the reaction with Folin-Ciocalteu reagent. The unit of proteolytic activity was defined as the same as the batch system (one unit corresponds to 1μg tyrosin/min). Automatic and efficient filtrations and also sample injections were performed by the devised filtration unit using a fraction collector equipped with a filter-tube supplier an automatic sample injector. The on-line rapid estimation of protolytic activity was achieved by the useinputs and processings. The sampling frequency was 20h^-1 when 200μl of digests was of an A/D converter and a computer for data taken. The calibration curve of tyrosine was linear in the range of 10-50μg/ml, and the relative standard deviation was 2.35% (n=10) when 200μl of 25μg/ml tyrosine standard solution was injected. The proteolytic activities by this FIA method were agreed well with those by batch methd (correlation coefficient, r=0.998).

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A new system for measuring dynamic viscoelasticity has been developed. It is now possible to measure rapidly the properties of a small irregularly shaped sample such as a grain of cooked rice or a piece of noodle. The time dependence can also be investigated, because the sample is not destroyed. The sample is sandwiched between two plates which are a constant distance apart and vibrated in the shear direction by moving one of the plates. The other plate detects the response through the sample. To obtain the value of viscoelastici-ty independent of the sample size, one of the plates is made of a transparent acrylic board and the contact area between the sample and the transparent plate is measured by an imageprocessing device with a monitor camera. Viscoelastic moduli G' and G″ can be calculated from vibration applied and response of the sample, the sample thickness and the contactarea. As an application to quality evaluation, the viscoelasticity of three kinds of cookedrice was measured in this. system. The results of the measurement showed a tendencysimilar to those of sensory evaluation.

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This paper describes the seasonal changes in starch content of kiwifruit in relation to starch synthetase activity and also examines the properties of this enzyme in the two cultivars, "Hayward" and "Koryoku". The highest activity of starch synthetase was observed in the middle of October for "Koryoku" and in late October for "Hayward". The highest starch contents in "Koryoku" and "Hayward" were observed in the middle and late October or early November, respectively. These increases in starch coincided with the highest activities of starch synthetase. Starch content in early-ripening 'Koryoku' peaked around half a month earlier than in late-ripening "Hayward". Since the soluble solids content in "Koryoku" could not be used as a harvest index because suitable firmness was not kept, the highest starch content was selected as the index in a previous paper. Starch synthetase activity followed the pattern of increasing starch content during the maturation and could explain maturity. Starch synthetase activity is a better index of maturity than β-amylase activity, because it supports decreasing starch content during the harvest period of "Koryoku".

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