亚麻子发芽前后化学成分及抗氧化活性的研究

采用高效液相色谱-二级串联质谱(HPLC/MS²)技术对不同发芽时间(0~8天)的亚麻子芽的化学成分进行鉴定。利用紫外分光光度法对亚麻子发芽前后的总黄酮和总多酚类成分进行定量分析，并采用铁离子还原能力法(FRAP)、自由基清除能力法(DPPH)和氧自由基吸收能力法(ORAC)对亚麻子芽的抗氧化活性进行评价。采用Phenomenex ODS C18色谱柱(4.6 mm×250 mm×5 μm)，以甲醇-0.2%乙酸水溶液为流动相进行线性梯度洗脱，流速0.75 mL/min，柱温25 ℃，全波长扫描紫外检测器(DAD)，检测波长为280 nm；采用电喷雾离子源(ESI)在正、负离子模式下进行检测。相比于亚麻子，在亚麻子芽样品中鉴定出12种新化合物，包括糖类、嘌呤类、核苷类和黄酮类化合物。对这12种化学成分进行定量和抗氧化活性分析，结果表明，随着发芽时间的增加，亚麻子芽中的总黄酮、总多酚类成分的量以及抗氧化活性逐渐增加。该方法可为亚麻子作为保健品以及功能性食品的原料提供理论依据。

Chemical Constituents and Antioxidant Activity of Flaxseed during Germination

Flaxseed has been widely used in a variety of applications for over 100 years, due to its reputation for cosmetic and health benefits. The germination may be enhanced the efficiency of flax seed, but there is a lack of scientific evidence supporting this inference. In order to clarify this problem, the phytochemical composition of flaxseed with different germination time (from 0 day to 8 days) was identified by using high performance liquid chromatography-diode array detector coupled with two-stage tandem mass spectrometry (HPLC/MS²). The separation was performed on a Phenomenex ODS C18 column (4.6 mm×250 mm×5 μm), of which 0.2% aqueous acetic acid (V/V) (A) and methanol (B) were used as the mobile phase. The flow rate was 0.75 mL/min. The column temperature was maintained at 25 ℃. The diode array detector (DAD) detection wavelength was set at 280 nm. MS analysis was carried out by the electrospray ionization ion source (ESI) in both positive and negative ion modes. The total flavonoid content (TFC) and the total phenolic content (TPC) in flaxseeds before and after germination were measured by UV spectrophotometric method. Furthermore, the antioxidant activity of flaxseed was evaluated by the ferric reducing antioxidant power (FRAP), DPPH scavenging (DPPH) and oxygen radical absorbance capacity (ORAC) assays. Compared to the non-germinated flaxseeds (0 day), twelve compounds were identified in partially germinated seeds and sprouts (day 1-8), including sucrose, nucleosides, purines and flavonoid. The TFC, TPC and antioxidant activities were found to increase as the flaxseeds germinate. This research shows that germination is a good process to increase the flavonoid content of flaxseeds as well as the antioxidant activity, and it provides a reliable theoretical basis for development of flaxseed as health care products and functional food.