The effect of pH on the relationship between hydrophilic/lipophilic characteristics and emulsification properties of soy proteins

Hydrophilic characteristics of four soybean protein isolates, determined through measurement of spontaneous water absorption capacity (WAC), were greatly affected by pH in the range of 2 to 7. While minimum WAC was apparent near the isoelectric region and increased away from the pI (isoelectric poin...

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Autores principales: Elizalde, B.E., Bartholomai, G.B., Pilosof, A.M.R.
Formato: JOUR
Materias:
Glycine max
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00236438_v29_n4_p334_Elizalde
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_00236438_v29_n4_p334_Elizalde2023-10-03T14:33:59Z The effect of pH on the relationship between hydrophilic/lipophilic characteristics and emulsification properties of soy proteins Elizalde, B.E. Bartholomai, G.B. Pilosof, A.M.R. Glycine max Hydrophilic characteristics of four soybean protein isolates, determined through measurement of spontaneous water absorption capacity (WAC), were greatly affected by pH in the range of 2 to 7. While minimum WAC was apparent near the isoelectric region and increased away from the pI (isoelectric point) for most isolates, a partially hydrolysed soy protein isolate behaved the opposite way. Lipophilic characteristics, determined as the spontaneous oil absorption capacity (OAC), varied up to 120% as pH changed. The balance between hydrophile and lipophile (WOAI), calculated as the ratio between WAC and OAC, showed a response to pH similar to WAC, with a minimum value near the pI, except for the hydrolysed isolate. Emulsifying capacity (EC) was maximum near the pI. However, the hydrolysed isolate showed a greater EC, reaching a maximum at pH 3, which could be attributed to peptides of different size and net charge with no single pI. As the hydrophilic/lipophilic balance reached lower values as a result of the effect of pH, EC increased, suggesting that a relatively high hydrophobicity is needed to enhance the EC of soy proteins. The effect of pH on emulsion stability was opposite to that shown on EC, except for the hydrolysed isolate, as maximum instability was apparent near the pI, where electrostatic and steric repulsions between oil droplets are highly decreased. The effect of pH on emulsion stability was closely related to WAC and indicated that a high hydration of the interfacial film is necessary for increasing stability against creaming and flocculation. ©1996 Academic Press Limited. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00236438_v29_n4_p334_Elizalde
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Glycine max
spellingShingle Glycine max
Elizalde, B.E.
Bartholomai, G.B.
Pilosof, A.M.R.
The effect of pH on the relationship between hydrophilic/lipophilic characteristics and emulsification properties of soy proteins
topic_facet Glycine max
description Hydrophilic characteristics of four soybean protein isolates, determined through measurement of spontaneous water absorption capacity (WAC), were greatly affected by pH in the range of 2 to 7. While minimum WAC was apparent near the isoelectric region and increased away from the pI (isoelectric point) for most isolates, a partially hydrolysed soy protein isolate behaved the opposite way. Lipophilic characteristics, determined as the spontaneous oil absorption capacity (OAC), varied up to 120% as pH changed. The balance between hydrophile and lipophile (WOAI), calculated as the ratio between WAC and OAC, showed a response to pH similar to WAC, with a minimum value near the pI, except for the hydrolysed isolate. Emulsifying capacity (EC) was maximum near the pI. However, the hydrolysed isolate showed a greater EC, reaching a maximum at pH 3, which could be attributed to peptides of different size and net charge with no single pI. As the hydrophilic/lipophilic balance reached lower values as a result of the effect of pH, EC increased, suggesting that a relatively high hydrophobicity is needed to enhance the EC of soy proteins. The effect of pH on emulsion stability was opposite to that shown on EC, except for the hydrolysed isolate, as maximum instability was apparent near the pI, where electrostatic and steric repulsions between oil droplets are highly decreased. The effect of pH on emulsion stability was closely related to WAC and indicated that a high hydration of the interfacial film is necessary for increasing stability against creaming and flocculation. ©1996 Academic Press Limited.
format JOUR
author Elizalde, B.E.
Bartholomai, G.B.
Pilosof, A.M.R.
author_facet Elizalde, B.E.
Bartholomai, G.B.
Pilosof, A.M.R.
author_sort Elizalde, B.E.
title The effect of pH on the relationship between hydrophilic/lipophilic characteristics and emulsification properties of soy proteins
title_short The effect of pH on the relationship between hydrophilic/lipophilic characteristics and emulsification properties of soy proteins
title_full The effect of pH on the relationship between hydrophilic/lipophilic characteristics and emulsification properties of soy proteins
title_fullStr The effect of pH on the relationship between hydrophilic/lipophilic characteristics and emulsification properties of soy proteins
title_full_unstemmed The effect of pH on the relationship between hydrophilic/lipophilic characteristics and emulsification properties of soy proteins
title_sort effect of ph on the relationship between hydrophilic/lipophilic characteristics and emulsification properties of soy proteins
url http://hdl.handle.net/20.500.12110/paper_00236438_v29_n4_p334_Elizalde
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