Enhancing the thermal and colloidal stability of lentil protein-stabilised emulsions using high pressure homogenisation pre-treatment

This study investigates the enhancement of thermal and colloidal stability of lentil protein-stabilised emulsions through high-pressure homogenisation (HPH) pre-treatments. Lentil protein dispersions were homogenised at pressures ranging from 0 to 150 MPa and subsequently used to formulate emulsions with 29 % w/w total solids, simulating a young child formula. Results indicated that HPH significantly improved protein solubility, increasing from 55.7 % at 0 MPa to 93.2 % at 50 MPa. In the emulsion system, particle size analysis showed a reduction in oil globule size, with diameters of 1.4 µm and 1.19 µm for the 0 MPa and 150 MPa samples, respectively. Emulsions prepared from HPH pre-treated dispersions exhibited greater physical stability, with separation rates decreasing from 16.75 %/h (0 MPa) to 2.05 %/h (150 MPa). Rheological analysis showed that HPH pre-treatments led to low initial viscosities (28.30 and 22.56 mPa·s at 0 and 150 MPa, respectively) as well as lower final viscosity (60.52 and 34.88 mPa·s at 0 and 150 MPa, respectively) after thermal treatment at 90°C for 2 min, compared with the untreated samples. Confocal laser scanning microscopy images showed a more homogeneous distribution of oil globules, and reduced flocculation, after the thermal treatment in emulsions prepared from HPH-treated dispersions. The results indicated an enhancement of the thermal stability of the HPH pre-treated samples, and this has been linked with the improved solubility of lentil protein following HPH treatment. These findings highlight the potential of HPH as an effective pre-treatment to enhance the techno-functional properties of lentil protein-stabilised emulsions, supporting the development of stable and sustainable plant-based food products.