The starch content in the fruits kept constantly low level through developmental period, while the sugar content rose sharply coincident with purple color development of skin surface of the fruits. Whereas α- andβ-amylase, α-glucosidase (maltase), β-fructofuranosidase (sucrase) and UDP glucose-fructose glucosyltransferase (sucrose synthetase) activities showed characteristic biphasic changes having two peaks. The first peak of these enzyme activities was found at an early stage of fruit growth, which corresponding to development of intrinsical flower (fruitlet) in the fruit. Their secondary peak was found in a final course of maturation. Preceding to an increase in the sugar contents, a sharp and transient increase of both α- and β-amylase activities were observed in about 10 days prior to the mature stage. Whereas α-glucosidase, β-fructofuranosidase and sucrose synthetase activities increased coincidently with increment of the sugar contents and turned to a sharp decline at the full ripening stage. The significance of these biochemical changes was discussed in connection with the fruit ripening.

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The first step of isolation of egg yolk immunoglobulin, IgG, a livetin protein, is to separate the water-soluble proteins from lipoprotein. A method for isolation of egg yolk immunoglobulin was investigated. Sodium casein was found to be effective for removal of yolk lipoprotein as a precipitate. Lipoprotein and water-soluble proteins were separated from egg yolk with sodium casein. More than ninety-nine percent of the lipids were precipitated by this treatment. After purification by ion-exchange chromatography, SDS-PAGE showed the presence of livetin protein in the supernatant. The lipopolysaccharide (LPS) was isolated from E. coli cells and used as an antigen for an ELISA. The LPS gave high sensitivity. The anti-E. coli IgY aggregated the bacterial cells and inhibited their growth in vitro.

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Homogenization process is crucial for the manufacture of liquid dairy foods. For fresh cream, even at the same fat concentration, homogenizing pressure generates great difference in not only its viscosity but other significant physical properties; which subsequently exerts vital influence on final product quality. Cream could be better expressed as mixed phase fluid. Hence, in this study, the particle size of fat globules in it was especially investigated as the factor which determines the viscosity of homogenized fresh cream, along with fat concentration and homogenizing pressure. The particle size distribution was measured in detail before and after being homogenized at various pressure points, and the changes in both particle size distribution and viscosity were examined. As aresult, volumetric specific surface area, which can be readily calculated from the particle size distribution, was found to be a suitable factor to express these changes. An empirical formula was proposed for their relations.

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Hydrogenation of soybean oil was conducted in 12l loop reactor equipped with venturi mixing nozzle to examine the reaction selectivity and rate. The reactor was compared with 1l dead-end type hydrogenator. Design of experiments was employed to evaluate the influence of reaction temperature, flow rate of soybean oil, hydrogen pressure and reaction time on selectivity and formation of trans isomer. Results showed that the flow rate of soybean oil which represents degree of mixing soybean oil, hydrogen, and catalyst in the loop reactor, was dominant among the reaction conditions affecting hydrogenation carried out in the loop reactor. The greater the flow rate of soybean oil, the smaller the selectivity was observed. Formation of trans isomer was depressed at greater flow rate of oil and at higher reaction temperature within the reaction conditions examined here. Reynolds number was adopted in this study to compare degree of mixing reactants and catalyst in both type of hydrogenators. Reynolds number showed positive correlation with reaction rate. At same Reynolds number (Re_??_4900), both hydrogenators exhibited almost same reaction rate. However, greater degree of mixing could be obtained in loop reactor than in dead-end type hydrogenator, with respect to actual hydrogenation process. Therefore, loop reactor equipped with venturi mixing nozzle has advantages as mentioned above for soybean oil hydrogenation.

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Toasting process of bread has been studied experimentally to explore the effects of the initial water content of bread and the radiative characteristics of a heater. White bread was employed as a sample, whose water content was controlled from 37.5% to 47.5%. Three kinds of electric heaters, whose radiative characteristics were different each other, were used. The radiative heat flux from the heaters to bread was controlled to be a constant. Experimental results show that, if the initial water content of bread is increased, the crust layer is formed slower and its layer is more wet. If the bread is toasted by the heater of longer wave length, the crust layer is formed faster and its layer is dry. During toasting, the water content of the crumb firstly decreases with time, takes a minimum, then increases, and goes beyond the initial water content of the bread. It takes a maximum just before the time at which all of the crumb turned to the crust. If the initial water content of the bread is higher or the wave length of the heater is longer, the water content of the crumb increased.

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Physical properties of no-retort and retort tofu which were treated by microbial transglutaminase (MTGaSe) were investigated. The ε-(γ-Glu) Lys bond (G-L bond) in tofu increased by addition of MTGase, and physical properties of tofu changed in connection with the increase in the amount of G-L bond. Namely, a breaking test of tofu treated with MTGase showed breaking Strength of both no-retort and retort tofu increased, and then it was constant in more than 2-5u/g protein. On the other hand, on a creep test of MTGase treated tofu, elastic modulus E_H of Hookean body decreased, and viscosity η_N of Newtonian body, elastic modulus E_V and viscosity η_V of voigt body increased. The retardation time λ of tofu decreased by addition of MTGase. A function for retort-resistance of tofu by addition of MTGase was remarkable from these changes of creep characteristics.

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It is well known that ergosterol (provitamin D₂) transforms to vitamin D₂ by ultraviolet light irradiation. We studied efficient transformation of ergosterol to vitamin D₂ in the materials (shiitake (Lentinus edodes), enokitake (Flammulina velutipes), hiratake (Pleuntus ostreatus), bakers' yeast, beer yeast and koji mold). Each powdered material was irradiated by ultraviolet light under vibration conditions. It was confirmed that a portion of ergosterol in all the materials was transformed vitamin D₂ by the treatment mentioned above. Yield of vitamin D₂ increased over 1000IU/g in every material for only 3 minutes. Yield of vitamin D₂ tends to increase with high contents of ergosterol. Yields of vitamin D₂ in shiitake under vibration conditions increased linearly up to 10 minutes and reached 10000IU/g. On the other hand, yield of vitamin D₂ in shiitake under stationary conditions was 2500 IU/g for 10 minutes. Transformation efficiency between the two was 4-fold. Thermostability of vitamin D₂ in shiitake was equal to that of vitamin D₂ in cellulose powder. Storage stability was superior to the control. It was thought that these fortified materials were of great value as additives in the field of food, petfood and feed

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A calcium preparation made from oyster shells with ohmic heating was examined on its applicability to meat and fish processing. Samples were mixed with the calcium preparation or dipped into a water suspension of the calcium preparation. It increased moisture content of products and improved those tenderness estimated by a sensory evaluation. The improvement in tenderness induced by the calcium preparation was also demonstrated with a rheometer.

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The successive treatments with acid and alkali were successfully applied to macerate the dietary fibers of Okara as follows. One gram of wet Okara washed with water was first immersed in 10ml of 0.08M hydrochloric acid at 25°C for 2h. The Okara was then washed with water by suction filtration with a glass filter (3G1). The Okara treated with acid was stirred in 10ml of 0.1M sodium hydroxide solution at 25°C for 40min by a magnetic stirrer and filtrated by suction with a filter. It was found that the masses of ruptured cotyledon cells, main component of fibers in Okara prepared by a tofu manufacturer, were macerated and passed through the filter by the treatments and suction, but fragments of seed coats were neither macerated nor passed through the filter. Okara without fragments of seed coats prepared in a laboratory scale was found to be completely macerated by the treatments. Complete maceration of Okara without fragments of seed coats in large quantities (50-70g) required the blend in a blender like a Waring Blender after the successive treatments with acid and alkali. Macerated fibers prepared by this method were pasty, and soft and pleasant in the plate. The macerated fibers contained more than 50% (d.b.) dietary fibers.

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The headspace volatiles (HSV) of cooked onions and the odor concentrates of those which were prepared by simultaneous distillation and extraction (SDE) were analyzed by capillary gas chromatography (GC)and gas chromatography/mass spectrometry (GC-MS). As for the HSV analyses, a thermal desorption cold trapping method was used on injection to GC column. Both sliced and whole onion bulbs were used for sample preparation. Boiled, baked and microwave cooked onions were prepared. A total of 50 volatile compounds were identified from these cooked onions. The main component of cooked onion slices was dipropyl trisulfide which was scarcely found in cooked whole onion. Disulfides and trisulfides containing propenyl group were main components of the latter. Furans, including furfural, were the main compounds of baked onion which possessed a very sweet odor. The thermal degradation products of sugars Seemed to contribute to the sweet flavor of cooked onion.

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