Lentil protein isolate suspensions with improved solubility and colloidal stability using high pressure homogenisation treatments

Lentil protein has generally good techno-functional properties; however, the limited solubility of lentil protein is a barrier to its wider use in food applications. This study aimed to evaluate the impact of high-pressure homogenisation (HPH), in the range 0–180 MPa, on selected techno-functional properties of lentil protein isolate (LPI) suspensions. The results showed that the low solubility (62.8 %) of LPI is mainly attributed to hydrophobic interactions and hydrogen bonds. Treatment with HPH at 180 MPa was effective in increasing this solubility to 95.3 %. The weighted mean volume diameter of particles in the suspensions decreased from 10.7 ± 1.1 (control) to 0.33 ± 0.06 µm (180 MPa), with this reduction in particle size attributed to physical disruptions/breakage of powder particles and of insoluble protein aggregates. Surface hydrophobicity increased from 614 to 1312 on HPH treatment, due to the exposure of previously-buried hydrophobic groups. The physical stability of the suspensions increased with increasing pressure, as evidenced by the separation rate decreasing from 8.55 % to 4.92 %/h for the control and 180 MPa treatments, respectively. These results indicate that HPH is a promising processing strategy to develop colloidally stable lentil protein suspensions with enhanced solubility and improved techno-functional properties for use of lentil protein ingredients in sustainable food products.