Effect of high-pressure homogenization pretreatment on gelation behavior and physicochemical, rheological and structural properties of sesame protein isolate with glucono-δ-lactone

Abstract

This study investigated the gelation of sesame protein isolate induced by high-pressure homogenization (HPH) with glucono-δ-lactone (GDL) acidification, focusing on the effect of pressures on gelation behavior and physicochemical, rheological and microstructural properties of the resulting gels. The HPH significantly affected the acidification kinetic parameters such as Vmax, Tmax, T5, and T4.5. The maximum Vmax (0.062 pH units/min) value was determined in the sample treated with 100 MPa, and T4.5 was decreased by 30 min with HPH at 50 and 100 MPa pressures. The particle size of sesame protein decreased with the homogenization pressure increased, and this played a role in the formation of lower particle size aggregates after gelation. The highest water holding capacity (69.02%) and gel strength (7.9 g) were reached with a pressure at 100 and 150 MPa, respectively. While a significant increase in the whiteness index of gels was observed by increasing pressure up to 100 MPa, the highest total color difference (ΔE) was detected at 50 MPa. The G′ value of the samples tended to increase with gelation time and with the high pressure applied, indicating a significant improvement in the elasticity of the gels. All gel samples exhibit shear-thinning behavior. Hydrophobic interactions were dominant in the gel samples, and the highest value (8.28 mg/g) was determined in the sample prehomogenized at 100 MPa. This study revealed that the gelation properties of sesame protein induced by GDL can be improved with HPH and that 100 MPa pressure application is ideal.