Changes in viscosity and amounts of sulfhydryl groups of soy bean milk(protein, 4.8%)by heating were investigated. The heated milk was ultrasonicated at room temperature to clarify the effects of ultrasonication on the aggregation of soy bean proteins. The results obtained were as follows: 1)When the milk was heated in 90°C bath, amounts of sulfhydryl groups increased within 1 min., and decreased after 2 min., showing decrease of 7S proteins. Viscosity of the milk increased at the same time. But the viscosity of the milk masked with N-ethylmaleimide(NEM) increased more rapidly during heating for 8 min. The existence of sulfhydryl group was assumed to be not necessary for the aggregation of the protein. 2)Soy bean milk was heated in water bath(90°C)to reach 80-85°C and ultrasonicated after cooling. Viscosity of the milk decreased within 30 sec., and the amounts of sulfhydryl groups increased rapidly. By the ultrasonication, decomposition of a component of 11S proteins was observed which lead to decrease of the viscosity and increase of the sulfhydryl groups. These results were confirmed by a successive process, such as heating, sonication, heating, sonication and re-heating.

View full abstract

By using silica gel column chromatography, the amounts of malic, citric, tartaric and quinic acids of green and roasted coffee beans were determined. Among these acids, the average quinic acid content was as follows: green beans 1.31%, medium roast 1.38%, French roast 0.47%, ice roast 2.08% and Italian roast 1.67%. In the course of roast, the quinic acid content increased slightly during medium roasting and then decreased rapidly by the the thermal decomposition. But a remarkable increase was observed after French roasting. From this fact, it can be concluded that after French roasting, quinic acid is liberated from brown pigments, which are produced by the thermal reaction of sucrose and chlorogenic acids.

View full abstract

An investigation on the influences of salt concentration in water phase(sodium chloride(%)×100/sodium chloride(%)+moisture(%))and inoculum size of S. rouxii on lactic acid fermentation in salty-rice-miso was carried out to obtain the following results. (1)It was recognized that salt concentration in water phase had a remarkable influence on lactic acid fermentation in miso. When its concentration was over 22%, lactic acid production was hardly seen, even if the initial level of the viable cells of Pc. halophilus was 10⁶ per gram.(2) Lactic acid fermentation was inhibited remarkably by the presence of over 1% ethylalcohol in green miso.(3) No lactic acid fermentation took place in ripening of miso unless the amount of living cell of inoculated Pc. halophilus was more ten times than that of S. rouxii. As the results, the growth of lactic acid bacteria was considered to be inhibited definitely by the presence of yeast, although the mechanism of the inhibitory effect was not yet clarified.

View full abstract

Changes in chemical and organoleptic properties of a retortable pouched Hamburg steak, one of typical fatty foods, were investigated under various conditions of storage temperature, oxygen permeability of pouch and exposure to light as variables. Peroxide value, TBA value and organoleptic properties were measured in order to evaluate the quality changes of the Hamburg steak during storage at 30°C and 40°C for 146 days.(1)Oxygen permeabilities of PVDC laminates decreased during storage.(2) The rates of lipid oxidation and the changes in taste of the Hamburg steak correlated to oxygen permeability levels of packaging materials.(3) Undesirable changes in the Hamburg steak were enhanced by prolonged exposure to light, as well as rapid oxygen permeation through some of tested packaging materials.(4)Storage temperature had a definite effect on deterioration of the organoleptic properties, but not always affected the chemical changes.(5)Packaging with plastic films of low oxygen permeability and storage under dark conditions are effective to improve the storage stability of fatty foods packaged in retortable pouches.

View full abstract

In order to develop a technique to extend a use of wheat flour by changing its protein content, visco-elastic behavior of air-classified wheat-flour dough was studied. Soft wheat flours containing 30% and 10% of domestic wheat flour were air-classified. Ten kinds of dough containing 5.4-10.1% and 8.1-25.3% of protein were prepared to measure viscoelasticity (V. E). Elasticity increased and viscosity decreased according to the increase of oscillation. V. E. also increased according to the increase of the protein content in the high protein range. Effect of glycolipid and the ratio of gliadin to glutenin were investigated to know the reason why V. E. of the air classified flour dough was not proportional to the protein content in the low protein range. V. E. of the air-classified flour dough was always higher than that of a gluten fortified flour dough of the same protein content.

View full abstract

Nucleic acid related substances were separated by cation exchange chromatography. The analysis was carried out using a column of φ9mm×400mm packed with Hitachi Model 2613 cation exchanger, by the stepwise eluting method. GMP, CMP, AMP, Urd, Ura, Thy, Ino, and Xan could be separated by 0.05 M monopotassium phosphate-phosphoric acid (pH 2.9) as the first eluting solution, Hyp. and Guo. by 0.4M monopotassium phosphate-phosphoric acid (pH 3.7) as the second eluting solution, and Ado, Cyd, Gua, Ade, and Cyo by 0.4M monopotassium phosphate-potassium hydroxide (pH 5.4) as the third eluting solution. The Nucleic acid related substances in leafy vegetables (Cabbage, Chinese cabbage, Head lettuce) were determined by this method. The trace amounts of Ade, Gua, Ado, Guo, and Cyd were observed in these samples.

View full abstract

Stimulative effect on the fermentation by acetic acid bacterium No.2 strain(accepted from National Institute of Fermentation Technology, Ibaraki-ken)was observed when 1% white soysauce was supplemented to the basal medium. 1. Effective substances in white soysauce were separated into a neutral fraction which exhibited highly stimulative effect and an acidic fraction, by the chromatography employing a multi-column of Amberlite IR-120(H⁺)and IR-410(OH^-). 2. Effective substances in neutral fraction were considered to be composed of glycerol and monosaccharides, from the results of the further purification by active carbon-celite column, gel filtration on Sephadex G-15 and paper chromatography. 3. Stimulative effect of the acidic fraction was suggested to result from supplement of the organic acids such as lactic acid, succinic acid, malic acid and others by the bioautography of acidic fraction and organic acid components in white soysauce.

View full abstract

For the purpose of developing efficient methods to protect tomatoes from in-transit mechanical injury, vibration characteristics of a five-high stack arrangement of small type plastic containers, normally used for transportation, were analyzed. The resistivity against in-transit mechanical injury and creep response of tomato were also studied, using six cultivars of processingtomatoes: "Morioka 16", "Wase daruma", "Sugano", "Chiko 3", "Kagome 70" and "Kikko 413". The results obtained were as follows: 1. When the five-high stack arrangement of containers filled with the tomatoes were oscillated, the acceleration response in the top container was the highest and the transmissibility was 4.0 in the vibration range of 11Hz to 12Hz. 2. Under vibrating conditions, the tomatoes became softer and then cracked. The resistivity to intransit mechanical injury varied in cultivars tested. "Morioka 16" was the most resistant. The order of decreasing resistivity against damage was found to be: "Morioka 16", "Wase daruma", "Sugano", "Chiko 3", "Kagome 70" and "Kikko 413". 3. The tomatoes were most severely damagedin the bottom layer than in the any other layers in the container. With the increase of vibration acceleration level, damage increased more in the upper than in the middle layer. 4. Tomato was considered as Burgers model in creep respose. Element η₃ rather than element K₁ was closely related to the resistivity to in-transit mechanical injury.

View full abstract

Low-pressure storage of several fruits and vegetables were investigated using a simple experimental scale apparatus.(1)Ripening of tomato fruit harvested at both stages of mature green and light pink was delayed at 100mmHg and 20°C. Tomato fruit stored under the low pressure for 25 days showed a normal ripening after transfer to normal pressure at 20°C. At pressure of 300mmHg and a temperature of 20°C, ripening of tomato fruit was not inhibited. (2) Ripening of green-mature banana was delayed at 100mmHg and 20°C. Banana fruit stored under the low pressure for a month showed a normal ripening after transfer to normal pressure at 20°C, though black rot on stems was observed. At 300mmHg and 20°C, banana fruit can be kept for a period of in excess of 10 days as compared with that at normal pressure. Yellowing of banana pretreated with ethylene for 24 hr was delayed at 100mmHg and 20°C. But increases of sugars and softening were not inhibited under that condition.(3)Bartlet pear ripened after one month under low pressure storage(100mmHg, 6°C), while the fruit ripened after 17 days at normal pressure and 6°C.(4)Ripening of white plum was markedly delayed at 100mmHg and 20°C. However, at lower temperature(6°C), there was no difference between the ripening behavior in normal and low-pressure storage(100mmHg).(5)In the case of grapes, cultivar of Himrod seedless maintained good quality at 100mmHg and 6°C during storage, but cultivar of Meo Muscat did not.(6)The CO₂ production of green-mature banana in the low-pressure storage(100mmHg, 20°C)was one-third as compared with that in air, and ethylene was not measurable. On the other hand, CO₂ and ethylene production of banana fruit pre-treated with ethylene for 24 hr increased during the low-pressure storage. Tomato fruit stored at breaker stage showed a decrease of CO₂ and ethylene production during low pressure storage (100mmHg, 20°C).

View full abstract

In order to design various cooking apparatuses, it is necessary to measure cooking rates and establish a rate equation of cooking which is used easily.Thelmpact-penetration method was used for measuring the cooking rates, and the following cooking-rate equations were obtained for the cooking of radish and carrot slices.
For radish slice:
dx/dθ=6.43×10¹⁷exp(-3.05×10⁴/RgT)
(1-x)^2.5(x+0.02) (min^-1)For carrot slice:
dx/dθ=1.69×10¹⁸exp(-3.22×10⁴/RgT)
(1-x)^1.5 (min^-1)where x(-)is the cooking ratio, θ(min)the cooking time, T(°K)the cooking temperature and R_g=1.987cal/g-mol·°K the gas-constant.

View full abstract