莲子贮藏过程中可溶性糖的变化规律

Changes of soluble sugar in lotus seeds in storage by HPLC-refractive index detection

莲子在贮藏过程中易发生陈化和品质劣变。为探讨其陈化机理,采用高效液相—示差折光检测法对新鲜莲子和陈年莲子中5种可溶性糖(蔗糖、果糖、麦芽糖、葡萄糖和棉子糖)含量进行测定。结果表明,与陈化莲子相比,新鲜莲子中蔗糖含量最低,仅为0.573g/L;麦芽糖含量最高,达0.172g/L,而麦芽糖在储存1年后含量急剧下降,降幅达87%以上。麦芽糖和蔗糖的比值在新鲜莲子中达0.301,而在贮藏1年和5年之后的莲子中,仅分别为0.023和0.018。随着贮藏时间的延长,果糖含量上升,葡萄糖含量变化不明显,可溶性糖的总含量在贮藏过程中呈上升趋势。莲子中未检测到棉子糖。贮藏导致莲子可溶性糖含量发生变化,从而影响其内在结构。麦芽糖和蔗糖的比值及可溶性糖总量变化可作为评价莲子陈化的指标。

Lotus seed has always been regarded as precious food stuff for its rich nutrition health care ingredients and high medicinal value,but like other grains,aging deterioration also occurred during storage.Using HPLC—RI to analysis the 5kinds of soluble sugar（sucrose,fructose,maltose,glucose and raffinose）in lotus seeds with different storage years.The results showed that the sucrose content of fresh lotus seeds was the lowest,only 0.573g/L,but the maltose content was 0.172g/L,the highest in fresh lotus seeds.Maltose content declined significantly after storage one year,the decrease degree is more than 87%.The value of maltose：sucrose is 0.301 in fresh lotus seed,but reduced to 0.023 and 0.018 after storage for one and five years,respectively.With the extension of storage time,the fructose content in lotus seeds increased,and glucose content did not change significantly.The total soluble sugar content increased significantly.Raffinose was not detected in lotus seed.Storage resulted the sugar content changes in lotus soluble,thus affecting its internal structure changes.The value of maltose：sucrose and the content of total soluble sugar in lotus seeds can be used as indicator of the aging degree.