Determination of non-polar and mid-polar monomeric oxidation products of stigmasterol during thermo-oxidation

Oxidation products of stigmasterol were characterised by their polarity and molecular size using solid phase extraction (SPE) and high-performance size exclusion chromatography (HPSEC) methods. Monomeric oxides were studied further by GC–MS and GC–FID. The focus was on identifying and quantifying non-polar and mid-polar monomeric oxides after SPE fractionation. Commercial stigmasterol was subjected to 180 °C up to 3 h. Six oxidation products were identified by GC–MS in the non-polar and mid-polar monomeric fractions; all appeared during the first hour of heating. Quantification by GC–FID showed an increase in the non-polar and mid-polar oxidation products during the heating time, and their amounts reached values of 6.1 and 47.0 g/kg of commercial stigmasterol, respectively. Polar oxidation products commonly measured reached a value of 193 g/kg after 1 h of heating, while after 3 h of heating their concentration was only 164 g/kg. Since as much as 550 g/kg of stigmasterol was decomposed, the monomeric products explained only partly the stigmasterol loss. Dimeric and polymeric products contributed to 165 g/kg of the loss showing the importance of polymerisation reactions at 180 °C

Determination of non-polar and mid-polar monomeric oxidation products of stigmasterol during thermo-oxidation

Oxidation products of stigmasterol were characterised by their polarity and molecular size using solid phase extraction (SPE) and high-performance size exclusion chromatography (HPSEC) methods. Monomeric oxides were studied further by GC–MS and GC–FID. The focus was on identifying and quantifying non-polar and mid-polar monomeric oxides after SPE fractionation. Commercial stigmasterol was subjected to 180 °C up to 3 h. Six oxidation products were identified by GC–MS in the non-polar and mid-polar monomeric fractions; all appeared during the first hour of heating. Quantification by GC–FID showed an increase in the non-polar and mid-polar oxidation products during the heating time, and their amounts reached values of 6.1 and 47.0 g/kg of commercial stigmasterol, respectively. Polar oxidation products commonly measured reached a value of 193 g/kg after 1 h of heating, while after 3 h of heating their concentration was only 164 g/kg. Since as much as 550 g/kg of stigmasterol was decomposed, the monomeric products explained only partly the stigmasterol loss. Dimeric and polymeric products contributed to 165 g/kg of the loss showing the importance of polymerisation reactions at 180 °C

Production and characterization of alginate-starch-chitosan microparticles containing stigmasterol through the external ionic gelation technique

Stigmasterol - a plant sterol with several pharmacological activities - is susceptible to oxidation when exposed to air, a process enhanced by heat and humidity. In this context, microencapsulation is a way of preventing oxidation, allowing stigmasterol to be incorporated into various pharmaceutical forms while increasing its absorption. Microparticles were obtained using a blend of polymers of sodium alginate, starch and chitosan as the coating material through a one-stage process using the external gelation technique. Resultant microparticles were spherical, averaging 1.4 mm in size. Encapsulation efficiency was 90.42% and method yield 94.87%. The amount of stigmasterol in the oil recovered from microparticles was 9.97 mg/g. This technique proved feasible for the microencapsulation of stigmasterol