The relatinship between the composition of pectic substance fractions and the hardness of texture of ume apricot and of its two different types of pickles, a brined product preliminaly treated with Ca-lactate solution (Ume zuke) and dried salted product (Ume boshi), was investigated. The results obtained were as follows: (1) The relative hardness values for the texture of fresh ume fruit, the brined and the dried salted products were measured as 3.5, 3.1 and 0kg, respectively. (2) The polysaccharide compositions of 70% ethyl alcohol-insoluble substance (AIS) prepared from the above samples showed not much difference, consisting of 34 to 38% of pectic substance, 20 to 26% of crude cellulose and 18 to 24% of hemicellulose. (3) The methoxyl group content of pectic substance was decreased by salting the fruit. (4) During pickling the fruits after the treatment with Ca-lactate, a remarkable increase of the hexametaphosphate soluble pectin fraction in AIS was found, showing almost no change of the HCI-soluble pectin fraction. But in the course of pickling without Ca-treatment, as for the dried pickled product, the water-soluble pectin fraction in AIS was markedly increased, whereas the HCI-soluble pectin fraction was decreased. (5) Extreme increase of Ca-content in AIS occurred by the pickling after Ca-lactate treatment. It was presumably concluded that during the pickling, the increased of water-soluble pectin fraction cause the softening of texture of pickled ume product but the retention of content of HCI-soluble pectin fraction (Protopectin) and the increase of the hexametaphosphate-soluble pectin fraction improve the hardness.

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Endo-polygalacturonase (endo-PG) of Aspergillus niger was purified by (NH₄)₂ SO₄ precipitation, ion exchange chromatography on CM-Sephadex C-50, preparative isoelectric focusing and Sephadex G-75 gel filtration. The endo-PG I and II were purified approximately 260- and 280-fold, and they were found to have K_m values of 3.33 and 1.67mg/ml, respectively, from the LINEWEAVER-BURK plot. The molecular weights of endo-PG I and II were 46000 and 35000, and had an isoelectric point of pH 5.6 and 6.5, respectively. Endo-PG I was most stable at a pH range between 4.0 and 5.5. Endo-PG II was found to be stable at pH 2.5 to 4.0. However, the enzymes had optimum pH at 4.5, and their optimum temperature for the action was 55°C. They were stable at a temperature up to 45°C. Therefore, the two forms of endo-PG might differ slightly in the physical and chemical structure of their molecules in the mechanism of hydrolysis of pectic acid.

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Effects of three main components of soybean phospholipids, phosphatidylcholine(PC), phosphatidylethanolamine(PE) and phosphatidylinositol(PI), on the stability of model emulsion were investigated. In relation to the stability, transfer of phospholipids to each phases (emulsion, water and oil) separated during aging and interfacial tension at water kerosine interface were also examined. Comparing the stability against creaming of water-kerosine emulsions prepared with the three phospholipids, PI emulsion was the best and PC emulsion was the worst. Among the emulsions with two or three component systems of PC, PE and PI, better stability was generally observed for the emulsions containing a greater amount of PI or PE. Emulsifiers giving more stable emulsions against creaming showed lower interfacial tensions at the water-kerosine interface. Decrease of the interfacial tension in PC system during aging was very slow, suggesting that PC is adsorbed very slowly to the oil-water interface. Smaller amount of phospholipid transferred gradually to water phase during creaming, and in the oil separating stage of emulsion the most portion of phospholipid transferred to the oil phase.

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The manufacture of Tenobe-somen is completed with Yaku process in which the somen is stored in a store-house over the hot rainy season of Japan. The effect of Yaku was investigated by comparing somens after Yaku with those stored in a freezer without Yaku. When powdered somens were heated in water at 65-95°C, the somens after Yaku showed lower swelling and solubility than the ones without Yaku. One possible reason for the decrease of swelling and solubility by Yaku was thought to be a change of amylase activity which could give influence on gelatinization of starch. However, determination showed that the decrease of the amylase activity by Yaku was not so much; about 20% in reducing power and 30% in viscometry of starch paste. When wheat starch was heated in somen-extracts containing somen amylase, little or no difference of swelling and solubility was observed between the somens with and without Yaku. Even with heat-inactivated extracts, the difference was not significant. It was shown that amylase in the extracts and also in somen itself was inactivated rapidly by heating. Influence of amylase on swelling of cooked somen may be small, because of its heat-instability.

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Yield and chemical property of Yuzu (Citrus junos Sieb. ex Tanaka) juice produced using tree extractors such as a continuous Centrifugal-type extractor (spiral separator), a Belt-press extractor and an In-line extractor were examined. The yield of juice from the Centrifugal-type extractor was increased apparently about 10 percent more than that from the Belt-press extractorbecause of higher pulp volume. Juice from the Centrifugal-type extractor (CT juice) and the In-line extractor (IL juice) had lower acidity and higher soluble solid content than that extracted by the Belt-press extractor (BP juice). CT juice showed a higher b value on a color differential meter compared to BP juice although the recoverable oil from CT juice was one-half of that from BP juice, and this phenomenon should be attributed to the higher pulp volume. The total free amino acidsand the major free amino acids including asparatic acid, glutamic acid and asparagine were greater in CT and IL juice than in BP juice. The major volatile components of CT, IL and BP juice were terpene hydrocarbons (d-limonene, γ-terpinene and myrcene etc.). The terpene alcohol such as linalool in CT juice was higher in concentration than that in IL and BP juice. As mentioned above, the yield and quality of juice extracted by the three extractors were different from one another. The results of this investigation would suggest that the Centrifugal-type extractor as well as the Belt-press extractor could apply for extracting Yuzu juice because of high juice yield whereas large pulp volume.

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Using the DDS plate-and-flame module fitted with three kinds of RO membrane made from different materials (cellulose acetate, composite membrane, polyacrylonitrile (PAN)), operating conditions and comparison of each membrane's suitability to concentrate fruit juice were studied. The osmotic pressure of fruit juices and sugar solutions was measured by using RO equipment. The osmotic pressures of glucose and fructose were the same and 1.9 times greater than that of sucrose solution. The osmotic pressures of fruit juices of 10°, 20°, and 30° Bx were 11-15, 26-34, and 46-60 kg/cmcm², respectively. Sugar composition of fruit juice had great influence on the osmotic pressure. Using clarified juice, the variation of permeation rate with various pressures, temperatures, and flow rates was examined. The permeation rate dependency on flow rate and temperature was similar for each membrane, but the dependency on pressure differed slightly. The operating factor found to be most effective in increasing permeation rate was operating pressure, which was followed by temperature and flow rate.

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The contents of bitter substances and their seasonal changes in some varieties of citrus fruit in Japan were investigated with reference to bitterness of fruit juice. (1) Three methods for measuring naringin content were compared each other in the juice and the other parts of citrus fruit. The most accurate values were obtained by a high pressure liquid chromatography (HPLC) and the values close to those of HPLC by the potassium borohydride reduction method. However, a modified DAVIS' method gave misleading higher values. (2) The naringin content was 300-1200mg/100g in segment wall, central axis and albedo, and less than 100g/100g in flavedo and pulp (juice sacs). Each content of limonin was 1000-2000ppm in seed and less than 500ppm in peel and segment wall. In pulp, limonin content was less than 30ppm, and nomilin content was less than 10 ppm. The amount of these bitter substance decreased during ripening of fruit. (3) The content of the bitter substances was compared each other in various kinds of fruit juice prepared by using the four types of juice extractor. Its content varied in the range of 100-300%, according to procedures of the preparation. (4) In a sensory test, the minimum concentration of the above substances which was perceived bitterness by 50% of panel was 8mg/100g in naringin, 4ppm in limonin, and 3ppm in nomilin and by 100% of panel was 20mg/100g in naringin, 12ppm in limonin, and 8 ppm in nomilin.

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Polyphenolic substances were extracted with ethanol from the immature fruit of Satsuma mandarin (Citrus unshiu Marc.). The extract was fractionated into two lead precipitate fractions (F-I and F-II) and mother liquor fraction (F-III) by the reaction with lead acetate. F-I and F-II were obtained, respectively, under acidic and basic conditions. F-II was further separated into two fractions (F-II_A and F-II_B) by DEAE-cellulose chromatography. The polyphenolic substances responsible for the enzymatic browning were found in F-I and F-II_B. Absorption spectra and difference spectra of F-I and F-II_B were measured during the browning reaction by polyphenol oxidase of the immature fruit. These spectral profiles of the two fractions resembled closely those of chlorogenic acid. By the hydrolysis of F-I and F-II_B, caffeic acid and quinic acid were found as constituent of the polyphenolic substances. Two polyphenols (S₁ and S₂) associated with the enzymatic browning were detected in both F-I and F-II_B by two dimensional paper chromatography. The absorption spectra and color reactions of S₁ and S₂ were in good agreement with those of chlorogenic acid, although their R_f values were different from the values of chlorogenic acid, isochlorogenic acid and neochlorogenic acid. F-III containing phlorin was not oxidized by the polyphenol oxidase. From the above results, it was suggested that both S₁ and S₂, which were unknown chlorogenic acid analogues, play the most important role in the enzymatic browing of the immature fruit of Satsuma mandarin.

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Soybean protein gels containing vegetable oils (cotton seed, corn, rape seed, sunflower and safflower oil) were prepared successfully by using oil-lecithin mixtures which were prepared by evaporating ethanol after dissolving oils and soybean lecithin in ethanol. The hardness of the gels decreased almost linearly with, an increase of the oil content. Incorporation ratio of oil into gel was a little different depending on the kind of oil, but it increased almost linearly with increasing oil content. The order of organoleptic acceptability of the gels was rape seed>cotton seed>corn>sunflower>safflower oil.

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