INVESTIGADORES
AÑON Maria Cristina
artículos
Título:
pH-Induced Modifications in the Thermal Stability of Soybean
Autor/es:
PETRUCCELLI, S; AÑÓN, M.C
Revista:
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
Editorial:
AMER CHEMICAL SOC
Referencias:
Año: 1996 vol. 44 p. 3005 - 3009
ISSN:
0021-8561
Resumen:
pH-induced modifications in the thermal stability of soybean protein isolates were studied by
differential scanning calorimetry. The thermal stability of the 11S globulin was higher than that
of the 7S globulin and was very sensitive to pH changes. The glycinin denaturation temperature
decreased by 10 °C when the pH was increased from 6 to 11, while the 7S globulin denaturation
temperature did not change. At pH 11, soybean isolate gave only one endotherm representing both
globulins. 11S globulin underwent conformational changes as the pH increased, which were reflected
by lower cooperativity in the denaturation process. 11S globulin also had a higher activation energy
for the denaturation process than did 7S globulin. The activation energy of 11S globulin was higher
than that of 7S globulin (in the pH 6-10 range) and shows a maximum kinetic stability at pH 8.
The 7S and 11S globulin half-lives at different treatment temperatures were calculated to pHs
between 6 and 11, and thermal treatments causing different degrees of denaturation were carried
out to produce a maximum increase of the surface hydrophobicity (Ho). For thermally untreated
isolates, the increase in pH led to an increase in exposed hydrophobicity. The combination of pH
10-11 and thermal treatments at temperatures of about 65 °C led to higher exposure of hydrophobic
groups, conditions for which would be most suitable for obtaining isolates with a higher emulsifying
capacity. Denaturing thermal treatments at this pH value induced aggregation along with thus a
fall in Ho.
groups, conditions for which would be most suitable for obtaining isolates with a higher emulsifying
capacity. Denaturing thermal treatments at this pH value induced aggregation along with thus a
fall in Ho.
The 7S and 11S globulin half-lives at different treatment temperatures were calculated to pHs
between 6 and 11, and thermal treatments causing different degrees of denaturation were carried
out to produce a maximum increase of the surface hydrophobicity (Ho). For thermally untreated
isolates, the increase in pH led to an increase in exposed hydrophobicity. The combination of pH
10-11 and thermal treatments at temperatures of about 65 °C led to higher exposure of hydrophobic
groups, conditions for which would be most suitable for obtaining isolates with a higher emulsifying
capacity. Denaturing thermal treatments at this pH value induced aggregation along with thus a
fall in Ho.
groups, conditions for which would be most suitable for obtaining isolates with a higher emulsifying
capacity. Denaturing thermal treatments at this pH value induced aggregation along with thus a
fall in Ho.
-10 range) and shows a maximum kinetic stability at pH 8.
The 7S and 11S globulin half-lives at different treatment temperatures were calculated to pHs
between 6 and 11, and thermal treatments causing different degrees of denaturation were carried
out to produce a maximum increase of the surface hydrophobicity (Ho). For thermally untreated
isolates, the increase in pH led to an increase in exposed hydrophobicity. The combination of pH
10-11 and thermal treatments at temperatures of about 65 °C led to higher exposure of hydrophobic
groups, conditions for which would be most suitable for obtaining isolates with a higher emulsifying
capacity. Denaturing thermal treatments at this pH value induced aggregation along with thus a
fall in Ho.
groups, conditions for which would be most suitable for obtaining isolates with a higher emulsifying
capacity. Denaturing thermal treatments at this pH value induced aggregation along with thus a
fall in Ho.
-11 and thermal treatments at temperatures of about 65 °C led to higher exposure of hydrophobic
groups, conditions for which would be most suitable for obtaining isolates with a higher emulsifying
capacity. Denaturing thermal treatments at this pH value induced aggregation along with thus a
fall in Ho.