Effect NaCl, pH, and heating on the structure and gelling properties of pea protein

TY - CONF

T1 - Effect NaCl, pH, and heating on the structure and gelling properties of pea protein

AU - Zhang, Yi

AU - Herneke, Anja

AU - Langton, Maud

AU - Johansson, Mathias

AU - Corredig, Milena

PY - 2024

Y1 - 2024

N2 - Gelation is an important functional property of pea protein, and the soluble aggregates are generally considered crucial for gel formation. How will the gel properties be affected by aggregates at different length scales? This work aims to study the effects of NaCl (0.0–0.4 M), pH (3.5–8.5), and heating (20°C, 95°C) on protein structure and how they impact the gelling properties. The study found that protein solubility is lowest at pH 4.5 for different NaCl concentrations. The effect of salt on protein solubility varies at different pH. At pH 3.5, solubility decreases with increasing salt concentrations; while for pH 4.5–7, protein solubility decreases initially at lower salt concentration (0.05 M), and then increases with more salt. At pH 8.5, salt concentration has no significant influence on solubility. Heating induced extensive aggregation, causing an increase in turbidity and a decrease in solubility at NaCl concentrations ranging from 0.1–0.4 M. This was not the case for samples solubilized in only water. AFM results showed that heating decreased the size of aggregates in water at pH 3.5 and 8.5, while induced even larger aggregates at pH 4.5 and 6.5. The highest extent of turbidity (Fig. 1) was obtained at pH 4.5, which correlated with the lowest amount of α-helix structure confirmed by CD spectroscopy measurements. Gelation was also studied, and their microstructure was evaluated using SEM. The least gelation concentration varied from 20 mg/mL to 120 mg/mL depending on salt concentration, pH, and heating, indicating that these factors are effective ways to control the structure and properties of pea protein gel products.

AB - Gelation is an important functional property of pea protein, and the soluble aggregates are generally considered crucial for gel formation. How will the gel properties be affected by aggregates at different length scales? This work aims to study the effects of NaCl (0.0–0.4 M), pH (3.5–8.5), and heating (20°C, 95°C) on protein structure and how they impact the gelling properties. The study found that protein solubility is lowest at pH 4.5 for different NaCl concentrations. The effect of salt on protein solubility varies at different pH. At pH 3.5, solubility decreases with increasing salt concentrations; while for pH 4.5–7, protein solubility decreases initially at lower salt concentration (0.05 M), and then increases with more salt. At pH 8.5, salt concentration has no significant influence on solubility. Heating induced extensive aggregation, causing an increase in turbidity and a decrease in solubility at NaCl concentrations ranging from 0.1–0.4 M. This was not the case for samples solubilized in only water. AFM results showed that heating decreased the size of aggregates in water at pH 3.5 and 8.5, while induced even larger aggregates at pH 4.5 and 6.5. The highest extent of turbidity (Fig. 1) was obtained at pH 4.5, which correlated with the lowest amount of α-helix structure confirmed by CD spectroscopy measurements. Gelation was also studied, and their microstructure was evaluated using SEM. The least gelation concentration varied from 20 mg/mL to 120 mg/mL depending on salt concentration, pH, and heating, indicating that these factors are effective ways to control the structure and properties of pea protein gel products.

M3 - Poster

T2 - 6th Food Structure and Functionality symposium

Y2 - 6 October 2024 through 9 October 2024

ER -