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Volume 61 (2007)
- Issue 6 Pages 299-
- Issue 5 Pages 253-
- Issue 4 Pages 194-
- Issue 3 Pages 141-
- Issue 2 Pages 89-
- Issue 1 Pages 3-
Volume 61, Issue 4
Displaying 1-9 of 9 articles from this issue
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Interaction of Food Components and Na IonMidori KASAI2007 Volume 61 Issue 4 Pages 194-198
Published: 2007
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSChemical interactions between NaCl and proteins (ovalbumin from agent, ovalubmin from egg white, β lactoglobulin, soy beans globulin) were studied. There was no binding between any proteins used and Na ions except for β lactoglobulin. For the case of β lactoglobulin, there was a slight binding at only pH 9.0 although its amount was under the threshold value of salty taste. The difference NMR and FT-IR spectra between protein solution with NaCl and without NaCl was not observed for all the samples studied. It was suggested that the interactions between proteins to Na ions were very weak. The relationship between rheological properties of isolated soy protein sol and the dissolution of Na ion from the protein sol was studied. The rate of dissolution of Na ion from the mixture of NaCl and various kinds of protein sols was in the order of isolated soy protein>decomposed protein sol with coagulants by protease>protein sol with coagulant. The measurements of viscosity of protein sols showed that the higher the viscosity of the sample, the slower the rate of dissolution of Na ions from the mixtures of protein sols and NaCl. It was suggested that the viscosity of protein sols increased by the addition of NaCl, and the rate of dissolution of Na ion decreased with increasing the viscosity of protein sols, and the destruction of stereo structure of protein caused the decrease of viscosity of the sol together with the increase of dissolution rate of Na ions.View full abstractDownload PDF (5255K) -
Electrochemical Measurement of Na+ ActivityKumi YOSHIDA2007 Volume 61 Issue 4 Pages 199-204
Published: 2007
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSSalt taste assessment of cocked food containing various food ingredients, such as acids, amino acids, proteins, sugars, and etc, might become very complex. We tried to digitalize salt tasty by measurement of Na+ activity in various model food solutions, model gels and cocked food co-existing using two types of ion-selective electrode, ion-selective microelectrode and the other is ion-selective membrane electrode. Na+ activity was suppressed by co-existing with acetic acid, glutamic acid, albumin, agar, gellan gum, κ-carrageenan. In tofu gel and egg white gel the Na+ activity was also decreased. However, in gel food the effect of syneresis might be considered in the results of Na+ activity measurement.View full abstractDownload PDF (6243K) -
Takao NAGANO2007 Volume 61 Issue 4 Pages 205-209
Published: 2007
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSTofu is a popular and traditional Japanese food. It is formed by the formation of heat-induced gels of soybean proteins, leading to determine its texture. Salts are used as coagulants on an industrial scale for the preparation of tofu and strongly affect the gel formation of soybean proteins. This article focuses on effects of salts on physical properties and gel structures of tofu. We explain: 1) relationship between physical properties and gel structures of commercial tofu, 2) effect of different coagulants on physical properties and gel structures of tofu, 3) effect of sodium chloride on the gel formation of soybean protein isolate, 4) effect of sodium chloride on physical properties and gel structures of tofu.View full abstractDownload PDF (8766K) -
Tomoko ICHIKAWA, Michiko SHIMOMURA2007 Volume 61 Issue 4 Pages 210-216
Published: 2007
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSEgg sols diluted with various liquids are easily converted to soft and smooth gels by heating. In this paper, effects of various salts on the properties of the diluted egg and egg white gels were discussed. With univalent NaCl or KCl, the breaking strength of gels were lower than with divalent MgCl2 or CaCl2, though increased gradually with added salt concentration. The amounts of liquid released by syneresis from gels with divalent salt were significantly large compared with univalent salt.Moreover, the breaking strength of gels with same charge showed same behavior, by adjusting to the same pH value of the sols.
The results of saltiness sensory evaluation test by Probit method of egg white gels with various concentration salts added were as for lows: The hardness of gels showed little influence on the saltiness. With other salts substituted to 5% of NaCl, the saltiness was weakened with MgCl2 or CaCl2 contrasting to little ef fect with KCl.View full abstractDownload PDF (11096K) -
Hatsue MORITAKA2007 Volume 61 Issue 4 Pages 217-225
Published: 2007
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSThe sol-gel transition of agar, κ-carrageenan and gellan gum in the presence of sodium chloride were investigated by thermal and rheological measurements. The G′, G″ and DSC curves for the agar solution during cooling and heating were slightly affected by added sodium chloride. In respect of the κ-carrageenan and gellan gum solutions, G′ and G″ were increased, and DSC curve shifted to a higher temperature in the presence of sodium chloride. The rheological and thermal behavior in the presence of sodium chloride may have been affected not only by the change density of molecules but also by the gelation mechanism, since gelation of the gellan gum sol was much more accelerated than the κ-carrageenan.View full abstractDownload PDF (10714K) -
Keiko HATAE, Soichi ARAI2007 Volume 61 Issue 4 Pages 226-229
Published: 2007
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSThe salty taste strength of foods may not necessarily depend on their NaCl contents. The saltiness we feel often varies according to the physical properties of the foods that function in the mouth. However, no clear scientific information has been available up to the present.
With it as a background, we undertook a project research aimed at elucidating the relationship between the NaCl contents of foods and their saltiness. The following foods with different NaCl contents were prepared: egg white gel, 0.4-1.2% NaCl; soy protein isolate gel, 1.0, 2.0% NaCl; soy protein curd (tofu), 0.5, 1.0% NaCl; and agar gel, 0.8, 1.0% NaCl. Sensory tests using well-trained panel members were first carried out with these food preparations to define their saltiness in terms of salty taste efficiency ratio (STER). The tests gave the STER values ranging from 0.58 to 1.10. Physical data were also measured with the foods to obtain several of their parameters involving gelling properties. It was then tried to correlate the physical data with the STER values. We could not find any significant correlation as far as the same food was tested irrespective of its different NaCl content. However, all the foods we prepared were comprehensively submitted to the physical parameter-sensory score analysis, significant relation appeared (R2: 0.83) which were clearly represented by an equation as a function of breaking stress value. It was also suggested that the STER differences were generally larger between foods than within a food having different NaCl contents.
This project research is apparently the first that objectively expresses the saltiness of foods in relation to their physical properties. It would contribute to our scientific aspect on how the proper saltiness for cooking of foods varies depending on the physical properties.View full abstractDownload PDF (6489K) -
Kimiko NUMATA, Tadao KURATA, Kenji ICHIMURA2007 Volume 61 Issue 4 Pages 230-234
Published: 2007
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSThe volume of tapioca pearls soaked in alkali metal chloride solutions was large in order of RbCl, KCl, NaCl, and LiCl. The volume of tapioca pearls soaked in saccharide solutions showed a plus correlation coefficient at three degree temperatures. The hardness of tapioca pearls soaked in alkali metal chloride solutions was small in order of RbCl, KCl, NaCl, and LiCl. The hardness of tapioca pearls soaked in saccharide solutions showed a correlation at three degree temperatures. From the large number of dynamic hydration numbers of the coexisting materials, tapioca pearls soaked in alkali metal chloride and saccharide solutions were hard, while the volume was small. We found a reverse relationship between the hardness and the volume.View full abstractDownload PDF (4660K) -
Risa TOYOSAWA, Kiyokazu TAKASHIMA, Tohru MURAKAMI, Yukiho YAMAOKA, Izu ...2007 Volume 61 Issue 4 Pages 235-240
Published: 2007
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSLabyrinthulid is a micro-organisms with a wide tolerance to salinity and high concentrations of astaxanthin and DHA. We examined the effects of astaxanthin (free-type) and Labiyrinthulid,Thraustochytrium sp. CHN-1, on the body color of fish. Goldfish (Shubun-kin),Carassius auratus, were used in this experiment. No significant change in the body color of goldfish that were orally administered astaxanthin (1.6 or 16mg/kg body weight/day) was found. On the other hand, a fine reddish color was observed on the goldfish that were orally administered Labyrinthulid (160mg/kg body weight/day: 0.05mg/kg body weight/day as astaxanthin) for several weeks. Two weeks administration of Labyrinthulid also increased significantly the number of the reddish color cells in fish skin. These results indicated that (i) oral administration of astaxanthin contributes little body color improvement in goldfish,(ii) oral administration of Labyrinthulid improved remarkably the body color of goldfish, and (iii) Labyrinthulid promoted an increase in number of the reddish color cells in the skin of goldfish.View full abstractDownload PDF (8296K) -
Kentaro TANAKA, Shigeru OHDE2007 Volume 61 Issue 4 Pages 241-244
Published: 2007
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSSulfate can be incorporated into coral aragonite (CaCO3) by means of an ion-exchange reaction: CaCO3(s)+SO42-(aq)=CaSO4(s)+CO32-(aq). The equilibrium constant for this equation can be expressed as: Kso4=[CaSO4] [CO32-]/[CaCO3] [SO42-]. The equilibrium constant Kso4 and seawater [CO32-] change with temperature. From the above equation, it is expected that the sulfate content in a coral skeleton is inversely proportional to the carbonate concentration in seawater.
In order to understand the coprecipitation process of sulfate in a coral skeleton by evaluating the correlation between the sulfate content and the carbonate concentration or temperature of seawater, we determined the sulfate content in coral samples from Pohnpei (Micronesia), Khang Khao (Thailand), Cebu (The Philippines), Sakai Port (Wakayama), Rukan-sho and Mizugama (Okinawa). The sulfate content was approximately constant (0.566±0.064wt%), with the exception of the sample from Khang Khao (0.404±0.050wt%). There is no correlation between the sulfate content and the carbonate concentration or temperature of seawater. Therefore, the controlling factors for incorporating sulfate into coral skeleton is not only the carbonate concentration, but also other trace elements in the skeleton and the temperature dependence of the equilibrium constant.View full abstractDownload PDF (4186K)
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