Stability of pea protein isolate-γ polyglutamic acid stabilised O/W emulsion: Effect of oil fraction, salt, and temperature

Zhang, B. B. and Zhu, H. S. and Xie, X. H. and Liang, D. and Feng, J. and Shi, Q. S. and Liang, C. and Chen, K. and Ji, H. F. (2024) Stability of pea protein isolate-γ polyglutamic acid stabilised O/W emulsion: Effect of oil fraction, salt, and temperature. International Food Research Journal (Malaysia), 31 (6). pp. 1471-1479. ISSN 2231 7546

Pea protein isolate (PPI) exhibits amphipathic properties and low allergenicity. Nonetheless, the limited solubility of PPI at its isoelectric point (pI = 4.6) may hinder its efficacy in emulsion applications. Therefore, addressing this limitation of PPI is imperative. The present work thus investigated the influence of γ-polyglutamic acid (γPGA) on the quality of PPI-based emulsion. The results showed that as the concentration of γ-PGA increased from 0.05 to 0.50%, turbidity measurements for a PPI system within a pH range of 4.0 - 5.0 decreased from 0.79 to a minimum of 0.24, indicating that γ-PGA enhanced the hydrophilicity of PPIs, which might have been due to γ-PGA's ability to promote conformational stretching of PPIs. When oil fraction volume was increased from 1 to 3% (v/v), the emulsion particle size at pH 4.5 decreased from 2233.33 to 710.11 nm; however, further increase in oil volume resulted in larger emulsion particles. Compared with other groups with different oil volumes, the emulsion containing 3% (v/v) oil volume exhibited the lowest separation index during 21-day storage. Additionally, particle size and ζ-potential exhibited an increase with increasing NaCl concentration, indicating that the presence of ionic strength decreased the stability of the PPI-γ-PGA emulsion. Similarly, a corresponding increase in particle size was noted with increasing temperature. Consequently, the interactions between γ-PGA and PPI indicated a substantial potential for utilising γ-PGA in the stabilisation of PPI-stabilised emulsions under acidic conditions. The present work also provided fundamental theoretical insights into the application of PPI-γ-PGA emulsions across diverse environmental contexts.

Full text available from: Official URL: http://www.ifrj.upm.edu.my/31%20(06)%202024/08%20-...

Abstract

Pea protein isolate (PPI) exhibits amphipathic properties and low allergenicity. Nonetheless, the limited solubility of PPI at its isoelectric point (pI = 4.6) may hinder its efficacy in emulsion applications. Therefore, addressing this limitation of PPI is imperative. The present work thus investigated the influence of γ-polyglutamic acid (γPGA) on the quality of PPI-based emulsion. The results showed that as the concentration of γ-PGA increased from 0.05 to 0.50%, turbidity measurements for a PPI system within a pH range of 4.0 - 5.0 decreased from 0.79 to a minimum of 0.24, indicating that γ-PGA enhanced the hydrophilicity of PPIs, which might have been due to γ-PGA's ability to promote conformational stretching of PPIs. When oil fraction volume was increased from 1 to 3% (v/v), the emulsion particle size at pH 4.5 decreased from 2233.33 to 710.11 nm; however, further increase in oil volume resulted in larger emulsion particles. Compared with other groups with different oil volumes, the emulsion containing 3% (v/v) oil volume exhibited the lowest separation index during 21-day storage. Additionally, particle size and ζ-potential exhibited an increase with increasing NaCl concentration, indicating that the presence of ionic strength decreased the stability of the PPI-γ-PGA emulsion. Similarly, a corresponding increase in particle size was noted with increasing temperature. Consequently, the interactions between γ-PGA and PPI indicated a substantial potential for utilising γ-PGA in the stabilisation of PPI-stabilised emulsions under acidic conditions. The present work also provided fundamental theoretical insights into the application of PPI-γ-PGA emulsions across diverse environmental contexts.

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Item Type:	Article
AGROVOC Term:	yoghurt
AGROVOC Term:	milk
AGROVOC Term:	functional foods
AGROVOC Term:	fermentation
AGROVOC Term:	production
AGROVOC Term:	Bacteria
AGROVOC Term:	probiotics
AGROVOC Term:	microorganisms
AGROVOC Term:	melatonin
AGROVOC Term:	tryptophan
Geographical Term:	China
Uncontrolled Keywords:	γ-polyglutamic acid, pea protein isolate, stability, emulsion
Depositing User:	Nor Hasnita Abdul Samat
Date Deposited:	07 May 2026 04:44
Last Modified:	07 May 2026 04:44
URI:	http://webagris.upm.edu.my/id/eprint/4063

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