Departamento de Biotecnología y Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN, Unidad Irapuato, Apartado Postal 629, Irapuato, Guanajuato 36821, Mexico.
J Agric Food Chem. 2012 Nov 28;60(47):11704-13. doi: 10.1021/jf303332n. Epub 2012 Nov 14.
Fructan, as reserve carbohydrate, supplies energy needs during vegetative development, thereby exhibiting variations in its content and composition. Fructan metabolism in Agave tequilana Blue variety from 2- to 7-year-old plants was analyzed in this work. Soluble carbohydrates were determined at all ages. Fructan (328-711 mg/g), sucrose (14-39 mg/g), fructose (11-20 mg/g), glucose (4-14 mg/g), and starch (0.58-4.98 mg/g) were the most abundant carbohydrates. Thin-layer chromatography exhibited that 2-5-year-old plants mainly stored fructooligosaccharides, while 6-7-year-old plants mainly contained long-chain fructans. The fructan degree of polymerization (DP) increased from 6 to 23 throughout plant development. The 7-year-old plants mainly stored highly branched agavins. Partially methylated alditol acetate analyzed by gas chromatography-mass spectrometry reveals that fructan molecular structures became more complex with plant age. For the first time, we report the presence of a large number of DP3 (seven forms), DP4 (eight forms), and DP5 (six forms) isomers for agave fructans. Overall, fructan metabolism in A. tequilana displays changes in its soluble carbohydrates, DP, type, and fructan structures stored, along its developmental cycle in the field.
果聚糖作为储备性碳水化合物，可为营养生长提供能量需求，因此其含量和组成存在差异。本研究分析了 2-7 年生龙舌兰 tequilana 蓝变种的果聚糖代谢。所有年龄均测定了可溶性碳水化合物。果糖（328-711mg/g）、蔗糖（14-39mg/g）、果糖（11-20mg/g）、葡萄糖（4-14mg/g）和淀粉（0.58-4.98mg/g）是最丰富的碳水化合物。薄层色谱显示，2-5 年生植物主要储存果寡糖，而 6-7 年生植物主要含有长链果聚糖。果聚糖聚合度（DP）在植物发育过程中从 6 增加到 23。7 年生植物主要储存高度支链的蔗果三糖。气相色谱-质谱联用分析的部分甲基化糖醇乙酸酯表明，果聚糖的分子结构随着植物年龄的增加而变得更加复杂。这是首次报道龙舌兰果聚糖存在大量 DP3（七种形式）、DP4（八种形式）和 DP5（六种形式）异构体。总之，龙舌兰果聚糖代谢在其可溶性碳水化合物、DP、类型和储存的果聚糖结构及其在田间的发育周期中发生变化。
