巴戟天采后储存温度和时间对寡糖类成分的影响

Effect of Temperature and Time on Oligosaccharides in Freshly Harvested Morinda Officinalis during Storage

目的:考察巴戟天鲜品采收后,储存温度(25、4、-7℃)和储存时间(1~56 d)对寡糖类成分含量的影响。方法:利用高效液相色谱-蒸发光散射检测器(HPLC-ELSD)测定储存过程中D-果糖、D(+)-无水葡萄糖、蔗糖、1-蔗果三糖、耐斯糖、1F-果呋喃糖基耐斯糖的含量,色谱柱为Waters XBridgeTM Amide(250 mm×4.6 mm,3.5μm),流动相为0.2%三乙胺乙腈-0.2%三乙胺水溶液,梯度洗脱,体积流量0.8 mL·min^-1,柱温35℃,漂移管温度75℃,氮气流量2.5 L·min^-1。结果:25℃条件下,1-蔗果三糖、耐斯糖、1F-果呋喃糖基耐斯糖(DP 3、4、5)在储存过程中呈逐渐下降的趋势,而D-果糖、葡萄糖、蔗糖的变化则逐渐增加,表明在25℃储存时,巴戟天寡糖在有水分存在的条件下,发生水解反应,导致D-果糖、葡萄糖、蔗糖的增加,4、-7℃条件下储存各寡糖较稳定。结论:巴戟天采收后应快速干燥或低温保存,以防止有效成分发生水解。

Objective:To investigate the variation of oligosaccharides in freshly harvested Morinda officinalis stored at 25℃,4℃,-7℃for 56 days.Methods:The content of D-fructose,D(+)-glucose,sucrose,1-kestose,nystose and 1F-fructofuranosyl nystose during storage were determined by HPLC-ELSD.The analysis of oligosaccharides was performed on Waters XBridgeTM Amide column(250 mm×4.6 mm,3.5μm)with acetonitrile-water(0.2%triethylamine were added both in organic and aqueous phase)in a gradient elution mode at the flow rate of 0.8 mL·min^-1,the column temperature was maintained at 35℃.The draft tube temperature of ELSD was set at 75℃and N2 flow rate was 2.5 L·min^-1.Results:The content of 1-kestose,nystose and 1F-fructofuranosyl nystose of M.officinalis under the condition of 25℃were gradually decreased as the extension of time,while the trends of D-fructose and sucrose were quite the opposite.The results showed that when stored at 25℃,the oligosaccharides of M.officinalis were hydrolyzed in the presence of water,which resulted in the increase of D-fructose,glucose and sucrose.However,the contents of oligosaccharides in samples are all stable storaged at 4℃and-7℃.Conclusion:The fresh root of M.officinalis should be dried quickly or kept at low temperature in preventing the occurrence of hydrolytic reactions.