Evaluation of the relationship between the peptide profiles and the lipid-lowering properties of olive seed hydrolysates as a tool for tuning hypocholesterolemic functionality

Abstract

Olive processing generates large amounts of stones with high protein contents. Previous studies have demonstrated that Manzanilla variety olive seed proteins release peptides with lipid-lowering capacity. However, no work has demonstrated their roles in the overall hypolipidemic activity. Moreover, further studies using different olive varieties are required to propose a solid method for the exploitation of olive seeds. Twenty different olive varieties were employed in this work. Proteins were extracted using high-intensity focused ultrasound and digested with Alcalase. The released peptides were identified using proteomic techniques, and their capabilities to reduce the absorption of dietary cholesterol (by inhibiting cholesterol esterase enzyme, binding bile acids, and reducing micellar cholesterol solubility) or the biosynthesis of endogenous cholesterol were evaluated. Peptides with different lipid lowering capacities were obtained from all varieties although the genotype significantly affected the hypolipidemic characteristics. Univariate and multivariate statistical analyses showed strong correlations, positive and negative, between the presence of certain peptides in the hydrolysates and their capacity to reduce exogenous cholesterol absorption and endogenous cholesterol synthesis. Therefore, the selection of the olive seed genotype can direct its lipid-lowering properties, e.g., by promoting the reduction of dietary cholesterol absorption or the inhibition of cholesterol biosynthesis.