The viscosity of the liquid part of cooked soybean with sodium chloride and citric acid was investigated. (1) The viscosity of the liquid increased first with increase of the soluble protein from soybean at the initial Step of preservation period, and then by gelatinization of the protein. (2) Although dissolution of soybean protein was promoted by adding sodium chloride, the viscosity of the solution decreased with increase of the salt concentration in the range of 0.5-3.0%. (3) The viscosity of the seasoned liquid was decreased by the addition of magnesium and calcium salt, and ketp stably during the preservation period suggesting interactions between soybean protein and the salts were taken place.

View full abstract

The manufacturing process of innoxious "Ann" from beans (Butter bean, Phaseolus lunatus Linn) containing cyanogenic compounds was studied. The "Ann" used for the analyses was manufactured in a modern and an old factories and the amount of liberated hydrogen cyanide (HCN) in each process was estimated. Liberated HCN in the usual product of "Ann" was not detected by the picric test according to the method of "the Food Hygienic Law" in Japan, but the high amount of HCN was sometimes detected in the "Ann" produced under the conditions which the boiling or the "Shibukiri" process was imperfect. A part of HCN liberated from beans moved to the waste water, and its amount increased with increasing the temperature of soaking water of the beans. Liberation ratio of HCN in the soaking process was 30.2% in the modern factory and 21.3% in the old factory. ("Ann" ("Nama Ann") is a mashed and granulated product of boiled beans. "Shibukiri" is to remove the lye from beans by boiling.)

View full abstract

In order to investigate the behavior of liberated HCN during the process of "Ann" production, the "Ann" was produced on a laboratory scale. Through this experiment, attempts to increase the liberation ratio of HCN in a soaking process were made. (1) In the laboratory process, almost all amount of HCN was distributed in beans and in soaking water during the soaking process. During the subsequent "Shibukiri" process, 90% of HCN in the beans was vaporized. The liberation of HCN from beans occurred only in the soaking process and its amount was 14.3% of the total HCN which was to be generated from all of the cyanogenic compounds in the beans. (2) The optimum condition for the liberation of HCN in the soaking process was given at 50°C and pH 8.0. It did not occur at 70°C and above. (3) When the commercial enzymes such as cellulase, protease and pectinase containing hemicellulase were added to the soaking water to increase the liberation of HCN, the maximum liberation ratio became 53.3%. (4) The liberation ratio of HCN increased with increasing the ratio of soaking water to beans, and it went up to 50.4% at the water-beans ratio of 4 in case of Butter beans. ("Ann" ("Name Ann") is a mashed and granulated product of boiled beans. "Shibukiri" is to remove the lye from beans by boiling.)

View full abstract

The texture of soybean protein gel (bean curd) to which palm oil powder was added, has been investigated by using a texturometer and a rheometer (food elongating-compressing tester). Hardness of the gels increased almost linearly with the increasing amount of added palm oil as determined by both a 18φ cylindrical lucite plunger (texturometer) and a 15φ disk plunger (rheometer). There was a positive relationship between the hardness values of the gels evaluated by texturometry and those obtained by the organoleptic method. A positive relation was also obtained between the flavor and the oil content. The viscosity of soy milk increased sigmoidally with heating time at 50°C and its increasing rate was reduced by the addition of the oil. Higher the oil amount added, lower the gelling rate of soy milk was observed, when the soy milk was heated at 85°C with glucono-δ-lactone as a coagulant. The value of pH of soy milk lowered immediately after heating and no further change occurred by additional heating. It is considered that powdered palm oil delays gelation of soy milk in the presence of glucono-δ-lactone, providing the fine and hard gel structure.

View full abstract

Incorporation of palm oil into soybean protein gel and the role of 11S and 7S proteins in gel formation have been investigated. Powdered palm oil was incorporated into the gel completely on its addition up to 10% of the soy milk, and on above 20% addition about 70% of the oil added was incorporated. Microscopic observation of the gel showed that the size of lipid globule in the gel became larger as the oil content was increased, and the oil was dispersed heterogeneously by addition over 10% oil, The amount of lipid extracted from the gel by n-hexane and petroleum ether under a fixed extracting condition increased linearly with increasing oil content, but extractability was depressed with increasing oil content. The increasing ratio of hardness with an increase of the oil content in the whole soybean protein gel was larger than that in the defatted soybean protein gel. Water-holding capacity of both whole and defatted soybean protein gels increased with the oil content. The 11S protein apparently plays the main role in the formation of oil-added gel, but from the experiments On gelation of 11S protein, 7S protein and palm oil mixtures, the relative amounts of 7S protein and plam oil to a 11S protein amount were shown to affect fairly the texture of the gels.

View full abstract

A method to prepare immobilized urease on the inner wall of a glass tube by radiation-polymerization under frozen state was investigated. As a part of a continuous flow analyzer. i.e. Technicon Auto Analyzer II, the immobilized urease tube of 1cm length was set and used for the routine determination of urea. This flow-through system could measure urea concentration of up to 30mM at rate of 30 samples per hour. The system were possible to assay 2000 to 3000 samples, continuously in practice. The activity of the urease tube stored in a refrigirator maintained 94% of the initial activity after 115 days.

View full abstract

A simple method to determine urea using an ammonia electrode combined with the tubular immobilized urease prepared by radiation-polymerization under frozen state was investigated. There was not much difference among three commertial electrodes, in their response or diffusion properties to ammonia. In flow-through system of the ammonia electrode, 2 to 4 minutes was needed for each sample to measure ammonia. Moreover, the time to wash out adsorbed ammonia out of the immobilized ureaSe tube was also required 2 to 4 minutes. According to those results, a simple device of urea determination which required 10 minutes for one procedure was constructed. This device provided a linear calibration line in the range of 5×10^-5 to 10^-3M urea, and the slope was caliculated to be 24mV/log [urea].

View full abstract

A kind of dual walled capsule for encapsulation of oleoresins or essential oils was prepared by once spray drying process, and its characteristics was investigated. The dual walled capsules consist of some water-soluble parts in which oleoresins and essential oils are encapsulated with gum arabic and dextrin, and some water-insoluble parts encapsulated with fats and oils. These capsules showed a different dissolution profile, compared with single walled capsules and dry soluble types, A portion of oleoreSin holded in the dual walled capsules was dissolved at low temperature and the rest of it at high temperature. Moreover, when the dual walled capsules were stored, the loss of oleoresin in these capsules was lesser than that observed in single walled capsules and dry soluble types.

View full abstract

The moisture content, the rate of water absorption and the liberation ratio of HCN of Butter beans (Phaseolus lunatus L.) were measured after storing at various temperatures and relative humidities (R.H.). The controlled temperature at 15°C and R.H. at 65% were necessary for keeping or promoting the values of such qualities measured as above at the begining of storage. The higher or lower temperature and humidity in storage than those mentioned above gave the lower values of estimation for the qualities except for the moisture content. But the rate of water absorption showed the same value as estimated at the begining of storage when beans were soaked for a longer time, while beans stored at 50°C and 20% R.H. could not recovered the rate of water absorption as much as measured at the begining of storage. When beans were stored at 30°C and 85% R.H., the moisture content was increased, and the quality was deteriorated as a result of growing of mold on their surface.

View full abstract