The internal standard method and head space gas chromatography was developed to assess the aroma of coffee in order to use for quality control of ground coffee. (1) Gas chromatographic analysis and sensory test were carried out on roast coffee beans which were roasted according to the criterion conducted at factory. The standard aromagram showed good reproducibility on 10 samples. This fact shows the usefullness of the method for the quality control. (2)The ground coffees were stored in vacuum package, nitrogen displacement package and common air package for six months at room temperature. According to the peak height ratio of acetaldehyde to isobutyl aldehyde, the significant deterioration of quality was observed after four months in all three cases and this agreed with the results of sensory test. Although the sensory test could distinguish the difference of quality deterioration among three types of package, present method could not.

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Soybean cooking drain from a miso factory was treated by ultrafiltration and reverse osmosis to study the separation of low molecular weight solutes from high molecular weight ones, the recovery of valuable matters and the removal of BOD. The drain contained protein and sugar as valuable matters, and these components were fractionated and recovered by choosing appropriate ultrafiltration and reverse osmosis membranes. Removal of BOD, however, was insufficient, even though the tight reverse osmosis membrane was employed. High molecular weight solutes contained in this drain formed gel layer on membrane surface in both ultrafiltration and reverse osmosis and this layer affected water and solutes permeation phenomena. Performances of membranes with gel layer were very similar to those obtained in our previous studies treating model solutions.

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The gel layer formed on the ultrafiltration membrane in treatment of soybean cooking drain from a Miso factory was scratched out, and its characteristics were analyzed by total solid, total carbon and total nitrogen. Components accumulated in a gel layer were determined by gel chromatography. From these results, it became clear that the gel layer consisted of soybean protein and high molecular weight polysaccharides, and the accumulation of the former was much greater than that of the latter. Rejection ability of the gel layer for low molecular weight solutes was analyzed quantitatively by the method of steric hindrance-pore model developed in the model solution in our previous work. Rejections estimated by this method with some assumptions agreed well with experimental values. Thus, it was verified that this analytical method was useful for the actual waste water.

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This study was designed to observe chemical changes along with pectin-degrading and cellulolytic enzyme activities in two cultivars of guava during fruit maturation, ripening and storage. Total pectin content was 345. 9-396. 1mg/100g during maturation and 704. 8-804.0mg/100g in ripening in both cultivars. Protopection and water soluble pectin were predominant in matured and ripened fruits, respectively. Alcohol insoluble solids and acidity decreased in both cultivars; and pH was 4.2-5.0 in white and 4.0-5.2 in pink varieties during maturation, ripening and storage. Guava polygalacturonase and cellulase showed maximum activity at pH 5.5 and 6.0, respectively. Ripe guava showed polygalacturonase activity recognized only remarkably at full ripe and the activity increased further in stored samples. Guava indicated a little pectinesterase and cellulase activity and these were found to increase sharply at the stage from maturation to ripening. During the stages from immature to full ripe on the tree, ascorbic acid content increased gradually in both cultivars. During stages from ripe to full ripe, and storage for 10 days at 20°C; in white cultivar total ascorbic acid, ascorbic acid and dehydroascorbic acid contents were 149.9-273.5, 126.7-224.0 and 23.3-49.5mg/100g, respectively; and in pink cultivar these were 172.6-270.3, 146.2-203.8 and 26. 4-66.5 mg/100g, respectively. Ascorbic acid content was found to increase remarkably in stored fruits until decay or senescence of the fruits started.

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Determination method of various phosphates in food was developed. Five grams of sample were homogenized with 25ml of ice-cold 20% trichloroacetic acid(TCA)solution while cooling and centrifuged. Precipitate was extracted again with 20ml of TCA solution. Supernatants were mixed and made up to 50ml, One ml of the extracted solution was diluted with 300ml of 5mM EDTA·2Na-EDTA·4Na solution(pH 5.0)and the pH was adjusted to 5.0 with 1N NaOH, This solution was poured into anion exchange column(Dowex AG 1×4, 100-200mesh, chloride form, 1×60cm)and the column was washed with 100ml of the above 5mM EDTA solution. The ortho-, pyro-, tri-, and another poly-phosphates were separatively eluted with 200ml of 0.15, 0.26, and 0.38M KCI in 5 mM EDTA solution, and 100ml of 2N HCI solution. Eluted polyphosphates were hydrolyzed by heating with 5N HClO⁴, and reacted with 5% ammonium molybdate. Phospho-molybdate complex was extracted with n-butylacetate and absorbance at the wavelength of 310nm was measured. Total phosphate contents of 7 kinds of processed cheese samples were 1.21-2.20% and polyphosphate contents were 0.21-1.31%. Total and polyphosphate contents of 1 kind of ham and 6 kinds of sausage samples were 0.31-0.75% and 0.16-0.44%, respectively.

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The influence of various containers on preservation of Satsuma mandarin (Citrus unshiu Marc.) juice during storage was examined. The reconstituted juice (12° Brix) were hot-packed into the different containers, such as glass bottle, metal can(tin free steel) and plastic vessels etc., sealed and then cooled with water. The final juice products were stored at 37°C, 20°C and/or 5°C during 3 months, and examined at regular intervals for the changes of ascorbic acid, browning (OD 430 nm), hydroxymethyl furfural and sensory evaluation. The maintenance of juice quality in the standing pouch (oriented nylon/aluminium foil/polyethylene) and the paper cup laminated with aluminium foil/polyethylene were the same as that in the glass bottle or the metal can. Whereas, the two standing pouchs (viniridene oriented nylon/polyethylene and oriented nylon/polyethylene), which were permeable to oxygen, gave the lower ascorbic acid retention, the higher browning and bad sensory score. When using 250ml portions of juice, the aluminium foil/polyethylene bag in box without headspace, so-called ekitight container, kept the quality of juice more than the glass bottle which headspace volume was increased each time the juices were consumed. From these results, the distribution, use and handling of the plastic containers tested were discussed.

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Elemental concentrations in tea infusion were compared between two samples, one of which was prepared by the standard preparation that is the infusion was concentrated, dried and lied to ash, and the other was not pretreated. Analysis was carried out by using an inductively coupled plasmaatomic emission spectrometry. The concentrations of Ca, Mg, Al, Mn, Zn, B, P and K determined in tea infusion showed no significant differences between the both preparations. It is possible to assay directly elemental concentration in tea infusion without any pretreatment. By using the direct analysis method, the solubilities of minerals of tea into the infusion were determined on Sen-cha and Kamairi-cha.

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A new method, which took advantage of relative humidity(RH)and temperature, for gelation of lyophilized soybean proteins was developed. The method is essentially as follows: a lyophilized protein was kept in a desiccator containing a saturated K₂SO₄ solution, which shows RH level of 96%, for 2 days at 50°C. When an aliquot of phosphate buffer was added to the lyophilized protein in which moisture was absorbed, the lyophilized protein showed gel state. Gels with various properties were obtained by giving physical treatments to lyophilized proteins before allowing proteins to absorb moisture.

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