Direct saponification preparation and analysis of free and conjugated phytosterols in sugarcane (Saccharum officinarum L.) by reversed-phase high-performance liquid chromatography

• A method based on direct saponification followed by HPLC analysis was developed.
• Acid hydrolysis was used to determine the composition of ASGs and SGs.
• Among different parts of sugarcane, tips had the greatest amount of phytosterols.
• Glycosylated sterols are found as an important group of sterols in sugarcane.
• Red-rind sugarcane contained more β-sitosterol than green-rind sugarcane.

A simple method based on direct saponification followed by RP-HPLC analysis was developed for quantification of free and conjugated sterols in sugarcane. Acid hydrolysis prior to alkaline saponification was used to determined acylated steryl glycoside and steryl glycoside in sugarcane. The applicability and generality of this method were improved with intensive investigation. Compared to traditional solvent extraction method, this method was more time saving and appropriate for characterization of sterol fractions in sugarcane. This method was successfully applied for determination of free and conjugated sterols in different sugarcane samples. The results exhibited that stigmasterol (varied from 883.3 ± 23.5 to 1823.9 ± 24.5 μg/g dry weigh) and β-sitosterol (varied from 117.6 ± 19.9 to 801.4 ± 33.5 μg/g dry weight) were major phytosterols in the sugarcane sample, and their glycosylated forms accounted for almost 87.0% of stigmasterol and 87.5% of β-sitosterol in sugarcane, respectively. In addition, among other parts of sugarcane, tips contained the greatest amount of phytosterols.