Studies on the stability of 11S globulin from soybeans by differential scanning microcalorimetry

Danilenko, A. N.; Grozav, E. K.; Bikbov, T. M.; Grinberg, V. Ya.; Tolstoguzov, V. B.

doi:10.1016/0141-8130(85)90040-6

Cited by 22 publications

(11 citation statements)

References 5 publications

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“…Acid treatment led to extensive denaturation of glycinin and the partial denaturation of β‐conglycinin as indicated for the decrease of the denaturation enthalpy (Table 1). A shift of the peak temperature of β‐conglycinin to a lower temperature ( T d 60 °C), indicating a decrease in the thermal stability, was also detected, in agreement with that reported by Puppo and Añón,37, Hermanson38 and Danilenko et al 39 On the other hand, alkaline treatment led to extensive denaturation of β‐conglycinin and the partial denaturation and dissociation of glycinin, as suggested by the two overlapping peaks in the thermogram and enthalpy values obtained (Table 1). At pH 11 the unfolding temperature also shifted to lower values and the peak became wider, indicating a lower cooperativity.…”

Section: Resultssupporting

confidence: 91%

Electrorheological Effect of “Side‐on” Liquid Crystalline Polysiloxane

2008

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Liquid crystals have attracted great attention in the field of engineering. Their application to the development of screens and displays is a representative example of their unique properties, because it demonstrates their excellent molecular-orientation ability. To develop further uses of liquid crystals, we have investigated the electrorheological (ER) effect, in which viscosity is controlled by the strength of an applied electric field.Since the discovery of the ER effect by Winslow in 1949, [1] several ER fluids have been widely studied as smart materials for industrial uses. After extensive research on ER fluids, it has been found that side-chain liquid crystalline polymers (LCPs) show a relatively large change in shear stress upon applying an electric field, because the thermal motion of terminal mesogenic groups is independent from that of the polymer backbone. [2][3][4][5][6][7][8] In addition, ER effects of the side-chain LCPs have been commonly observed at temperatures above the clearing point. This observation can be attributed to the enhanced order, which results from the formation of the liquid crystalline phase. From a practical viewpoint, side-chain LCPs exhibiting a smectic phase have a high viscosity in the phase, which causes a poor response to the application of an electric field. This limits the temperature range at which ER effects can be measured when LCPs showing a smectic phase are used as the ER fluids. It is widely known that the viscosity in the smectic phase is usually higher than that of the nematic phase, in accordance with the different order parameters of the various liquid crystalline phases. The generated shear stress is defined as the difference between the shear stress in the presence and that in the absence of an applied electric field. Therefore, a lower shear stress in the absence of an electric field is expected to enhance the ER effect.

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Section: Resultssupporting

confidence: 91%

Electrorheological Effect of “Side‐on” Liquid Crystalline Polysiloxane

2008

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“…Nevertheless, after exceeding a certain NaCl concentration, the balance between repulsive and attractive forces necessary for the maintenance of a cohesive network is disrupted and the resulting protein over‐aggregation is reflected in precipitated networks of lower strength and reduced functionality (higher tan δ values). The work by Danilenko et al . (1985) and Damodaran (1988) on soybean proteins offers another insight on the destructive effect of excessive amounts of NaCl on a globulin network.…”

Section: Resultsmentioning

confidence: 99%

Physical characterization of thermally induced networks of lupin protein isolates prepared by isoelectric precipitation and dialysis

Kiosseoglou

Doxastakis

Alevisopoulos

et al. 1999

Int J of Food Sci Tech

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Summary Protein isolates of Lupinus albus were obtained from full fat and defatted lupin flour using isoelectric precipitation or dialysis. Calorimetric tests demonstrated that the main protein fractions of the isolates denature well below 100 °C. Mechanical spectra of isolate dispersions obtained at 80 °C indicated the formation of a ‘pseudogel’ whose cohesion increased during cooling to 10 °C. Subsequent heating to 90 °C encouraged extensive formation of disulphide bonds as it produced gels that were insoluble in sodium dodecyl sulphate and urea solutions. Dialysis produced isolates of lower gelling concentrations, which also formed networks of a stronger relative elastic character. The presence of NaCl at concentrations up to 0.5 m had a reinforcing effect on networks. Protein over‐aggregation caused the opposite effect at higher salt levels. Finally, a comparison with results in the literature on soybean protein gelation suggested similar denaturation temperatures and a common pattern of structure formation for the two legume proteins.

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“…Two endotherms corresponding to different species of glycinin were observed at pH 3.50 and 3.25 (data not shown). Danilenko et al (1987) reported with regard to glycinin (pH 3.25-3.75) one endotherm of higher and another of lower Td. These they assumed to be of the dodecameric and hexameric form, respectively, of globulin 11S.…”

Section: Effect Of Ph and Protein Concentrationmentioning

confidence: 97%

Soybean Protein Dispersions at Acid pH. Thermal and Rheological Properties

Puppo

Afñón

1999

Journal of Food Science

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The influence of pH, protein concentration, and ionic strength, on rheological properties of thermally treated acidic soy protein dispersions, was studied. Structural changes due to pH effect and thermal treatment were analized. DSC-thermograms at pH 3.5 showed a shoulder at 74.1160.168C that could be attributed to both b-conglycinin and the hexameric form of glycinin; and a peak at 81.8860.298C corresponding to 11S dodecameric form. At pH 2.75 one endotherm corresponded to denaturation of b-conglycinin. The acidic dispersions presented pseudoplastic behavior with h app values higher than those at pH 8.0. At pH 3.50 the h app was higher than at pH 2.75. The maximum viscoelasticiy was obtained with addition of 0.1 and 0.25M NaCl in the dispersions of pH 3.50 and 2.75, respectively. The increase in viscoelasticity was enhanced by the formation of 11S native fraction dimers.To prepare the acid isolates (pH 2.50, 2.75, 3.00, 3.25, and 3.50) and that at pH 8.0, the isoelectric precipitate was dispersed in distilled water and adjusted to the desired pH with either 2N HCl or 2N NaOH. Dispersions thus obtained were lyophilized.To determine the extent of influence of the pH treatment on protein denaturation, alkaline isolates previously modified by treatment at different pHs were also prepared. Different acid dispersions(pH 2.50-3.0) were prepared from the isoelectric precipitate, by adjusting the pH with 2N HCl; these dispersions were then kept at the corresponding pH for 1h at 20ЊC, and then adjusted to pH 8.0 with 2N NaOH prior to lyophilization. Preparation of 7S and 11S-enriched fractions

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Studies on the stability of 11S globulin from soybeans by differential scanning microcalorimetry

Cited by 22 publications

References 5 publications

Electrorheological Effect of “Side‐on” Liquid Crystalline Polysiloxane

Electrorheological Effect of “Side‐on” Liquid Crystalline Polysiloxane

Physical characterization of thermally induced networks of lupin protein isolates prepared by isoelectric precipitation and dialysis

Soybean Protein Dispersions at Acid pH. Thermal and Rheological Properties

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