A stigmasterol-rich phytosterol composition is prepared wherein the composition comprises at least 50% stigmasterol, based on the total weight of phytosterols, no more than 1000 ppm water, no more than 50 ppm ethanol, and wherein stigmasterol is at least 98% in the anhydrous form. A ready-to-freeze beverage is provided comprising the stigmasterol-rich composition and water, with optional additives. A frozen beverage is prepared from the ready-to-freeze beverage as a pourable slush. There are further provided processes to prepare the ready-to-freeze beverage and the frozen slush beverage.