Sterol stability in functional fruit beverages enriched with different plant sterol sources

Abstract

Two different plant sterol (PS) sources (free PS from tall oil and esterified PS from vegetable oils) were used for manufacturing two types of functional beverages (fruit and milk-based fruit beverages), and their PS and phytosterol oxidation product (POP) contents were determined. Gas chromatography–tandem mass spectrometry (GC–MS/MS) was used for identification and gas chromatography–flame ionization detection (GC–FID) for quantitation purposes. Brassicasterol, campesterol, campestanol, stigmasterol, β-sitosterol and sitostanol were the quantified PS, conforming a profile in order with current legislation. The relative percentages of PS differed according to the enrichment source involved, though the enrichment levels (g/100g beverage) were of the same order (1.77 from tall oil and 1.84 from vegetable oils). Only POPs from β-sitosterol (the prevalent PS in the analyzed beverages) were detected — the predominant representative being 7β-hydroxysitosterol (39–58.5% of total POP content). The following POPs were quantified: 7α-hydroxy, β-epoxy, α-epoxy, and 7-ketositosterol, yielding a total POP content ranging between 42.9 and 57.4mg/100g of PS. No statistically significant differences (p>0.05) in total and individual POP content according to the source of PS were found. The mean β-sitosterol oxidation percentage was <0.07%, which reflected a low PS oxidation extent, though manufacture was on a laboratory scale regardless of the PS source used in enrichment of the functional beverages. These functional drinks therefore can be regarded as healthy food products and as an adequate PS vehicle as well.