【作者】 冯思敏； 罗自生；

【Author】 Feng Simin;Luo Zisheng;Department of Food Science and Nutrition,Zhejiang University;

【机构】 浙江大学食品科学与营养系；

【摘要】 本文旨在建立一套基于酸碱直接皂化并结合高效液相色谱(HPLC)分析,能够有效测定甘蔗中自由态及结合态植物甾醇含量的检测方法。对酸碱直接皂化条件进行优化,同时建立了一套利用内标法测定甘蔗中不同形式植物甾醇含量的HPLC分析方法,最后将该方法成功应用于不同甘蔗样品中自由态及结合态植物甾醇的含量测定。结果:酸式皂化的最优条件是:0.5g甘蔗样品用5mL 4.0mol/,L HCl乙醇溶液在70℃条件下皂化1h,用10mL 4.0mol/,L KOH乙醇溶液在70℃条件下皂化1h。建立的HPLc检测方法在5~80μg/mL的浓度范围内具有良好的线性(R>0.999),各甾醇检测限LOD为0.85~1.01μg/mL,LOQ为2.84~3.35μg/mL,RSD为1.70%~4.81%,回收率为88.2%~108.9%。豆甾醇和β-谷甾醇是甘蔗中最主要的两种植物甾醇,其中最多有87.0%豆甾醇,87.48%β-谷甾醇是以与糖类的羟基形成糖苷键的配糖类化合物(SG)以及酰基配糖类化合物(ASG)形式存在的结合态植物甾醇。相比传统溶剂提取方法,本方法具有操作简单,节省时间、溶剂,更适合检测甘蔗中不同形态植物甾醇含量的特点。更多还原

【Abstract】 A simple,effective method based on direct acid and alkaline hydrolysis followed by HPLC analysis was developed and validated for quantification of free and conjugated sterols in sugarcane.In method development,the main focus was on optimization of hydrolysis conditions and on validation of HPLC method using an internal standard(6-ketocholestanol).At last,the method has been successfully applied for the determination of free and conjugated sterols in different sugarcane samples.The best optimal hydrolysis conditions were established as follows:0.5 g sugarcane sample refluxed with 5 mL 4.0 mol/L ethanolic HC1 solution for 1h at constant temperature 70 °C and then the mixture refluxed with 10 mL 4.0 mol/L ethanolic KOH solution for 1h at the same temperature.The calibration curve was drawn in the range of about 5 to80 μg/mL with a regression coefficient over 0.999.The limits of detection and limit of quantitation of the method varied from 0.85 to 1.01 μg/mL and 2.84 to 3.35 μg/mL,respectively.Relative standard deviations ranged from 1.70%to 4.81%and recoveries were from 88.2%to 108.9%.Stigmasterol and β-sitosterol were prevailing phytosterols in the sugarcane sample,and glycosylated sterols contributed up to almost87.0%of stigmasterol and 87.48%of β-sitosterol in sugarcane.Compared to solvent extraction method,the improved method proved to be more effective,solvent and time saving and appropriate for evaluation and characterization of sterol fractions in sugarcane.更多还原