Effects of pH and temperature on the stability of peanut oil bodies: New insights for embedding active ingredients

As a natural emulsion, peanut oil bodies (OBs) are often used to embed drugs and natural active ingredients. To improve the utilization rate of peanut OBs, it is thus necessary to study their stability under different environmental conditions (pH, temperature). There were differences in the content and composition of peanut oil body interface protein (OBIP) at different pH values. When the pH increased, exogenous proteins were eluted and the endogenous protein content increased. By analyzing the particle size distribution, the secondary structure of OBIPs, and the fatty acid composition of lipids in OBs, it can be concluded that their stability increased with the pH, and the special protein–phospholipid membrane protected the lipids from damage. Upon heating OBs with different pH at 30–90 °C for 30 min, the particle size and zeta potential of OB (pH 6.8) increased, and the OBIPs did not change, reducing the stability of the OB. The particle size distribution, zeta potential, and interfacial protein composition of OB (pH 8, 9, 10, 11) did not change significantly, and their stability remained unchanged. Therefore, when OB is used to embed active ingredients, OB should be purified and the heating temperature should not exceed 90 °C. [Display omitted] •Peanut OBs can be purified at alkaline pH with increased stability.•When peanut OBs were mainly coated with endogenous proteins with "heat resistance", the OBs stability remained unchanged.•The higher the endogenous protein content, the better the stability of peanut OBs between 30 and 90 °C.