Work

Using state diagrams to understand salt-dependent aggregation of β-lactoglobulin nanogel particle dispersions for conditions relevant to ultra-high temperature treatment

Year: 2026

Type: article

Abstract: Formulating shelf-stable, high-protein nutritional beverages at neutral pH requires controlling protein aggregation and gelation during heat treatment, where whey protein nanogel particles are a promising solution. However, our understanding of these particles is limited, especially above 130 °C. This study investigated the influence of sodium, potassium, calcium, chloride and phosphorus on aggregation and gelation of β -lactoglobulin ( β -lg) nanogel particle dispersions during ultra-high temperature (UHT) treatment. Gelation was assessed after UHT-mimicking treatment by visually classifying dispersions with varying protein (1–10 wt%) and salt (0–500 mM) concentrations as liquid or gel by inversion. State diagrams, separating liquid and gel regions following UHT treatment as a function of protein and salt concentration, were constructed for sodium chloride, potassium chloride, calcium chloride, sodium citrate and sodium phosphate using an optimized sequential sampling algorithm focused on experiments near the liquid-gel boundary, minimizing the number of experiments. Gelation was governed by protein concentration, salt-to-protein ratio, ion type, and pH. Higher protein concentrations lowered the salt threshold for gelation. Calcium reduced the salt concentration required for gelation to 0.8 mM at 1% protein, compared with 15 mM for sodium or potassium. Citrate shifted gelation to higher salt concentrations of 60 mM at 1% protein, relative to 15 mM for chloride or phosphate. pH values further from the isoelectric point increased salt tolerance before gelation. Aggregation could be observed below the gelation threshold. The state diagrams provide a framework for predicting heat-induced structuring and support formulation of high-protein beverages subjected to preservative heat treatments.

Source: Food Hydrocolloids

DOI: 10.1016/j.foodhyd.2026.113518