Form of phytosterols and food matrix in which they are incorporated modulate their incorporation into mixed micelles and impact cholesterol micellarization

Abstract

Scope: The ability of different plant sterols/stanols (PS) mixtures, which differed in the degree of B-ring saturation and aliphatic side chain structure and saturation, to reduce cholesterol (CH) micellarization was explored.

Methods and results: Experiments were performed using an in vitro digestion model, synthetic mixed micelles, and pure porcine pancreatic lipases. Sterols were measured by GC-FID. The ability of PS to reduce CH micellarization was dependent on the form of PS and on the type of delivery matrix (low-fat yogurt or olive oil). Long-chain PS esters delivered in the yogurt matrix, and medium chain PS esters delivered in olive oil provided the greatest reduction in CH micellarization. In yogurt, the ability to impair CH micellarization was inversely related (rho = -0.41, p < 0.0005) to PS melting point. In olive oil, the more hydrophobic PS mixtures, i.e. those rich in long-chain PS esters, had the lower ability to impair CH micellarization.

Conclusions: Different forms of PS have a different ability to impair CH micellarization. This ability depends on the transfer efficiency of PS from the food matrix to the micelle, which in turn depends on the melting point and the hydrophobicity of PS and on the delivery food matrix.

Keywords: Carboxyl ester hydrolase; Medium chain phytosteryl esters; Olive oil; Phytostanols; Yogurt.