Chapter 9 - β-Sitosterol as a functional bioactive

Abstract

Phytosterols are integral natural components of plant cell membranes and are abundant in vegetable oils, nuts, seeds, and grains. Phytosterols have multiple beneficial effects on human health, such as hypocholesterolemic, antiinflammatory, antibacterial, antifungal, and antioxidant activities. Evidence show that these bioactives play an essential role in the reduction of blood cholesterol, thus providing protection from the cardiovascular morbidity. β-Sitosterol is a significant member of the phytosterol group, which is found in cereals, vegetables, and fruits in concentrations of 0.24–0.61, 0.02–0.41, and 0.02–0.34gkg− 1, respectively. Vegetable oils are rich sources of β-sitosterol containing 0.24–8.79gkg− 1 (representing 33%–91% of total phytosterols); specifically, olive oil and olive pomace oil have a high β-sitosterol concentration ranging between 0.91 and 1.52gkg− 1 (representing 75%–90% of total phytosterols). Due to the functional role of phytosterols, especially of β-sitosterol, the conditions of use of their health claims are set out in the Commission Regulation (EU) No 686/2014. This chapter aims to discuss the chemical structure and properties, the role, and the functionality of β-sitosterol. The main sources of β-sitosterol focusing on vegetable oils, mainly olive oil and olive pomace oil, are also presented. The fate of phytosterols and especially of β-sitosterol during food processing such as oil refining and other processes (i.e., frying) is also discussed. Finally, the enrichment of various food systems with β-sitosterol including commercial fats, butter, and nanoemulsions are reviewed offering an updated glimpse of valuable applications of this functional component.