Food Technology Division, School of Industrial Technology, Universiti Sains Malaysia, 11700 Minden, Penang, Malaysia.
J Sci Food Agric. 2011 Dec;91(15):2731-9. doi: 10.1002/jsfa.4454. Epub 2011 Oct 10.
C. asiatica was exposed to various fermentations: no fermentation (0 min), partial fermentation (120 min) and full fermentation (24 h). Total phenolic content (TPC) and ferric-reducing antioxidant power (FRAP) of C. asiatica infusions were studied as a function of water temperature (60, 80 or 100 °C), the brewing stage (one, two or three) and the brewing time (1, 3, 5, 10, 15 or 20 min). The optimum brewing procedure was adopted to study the antioxidant properties and phenolic compounds in C. asiatica infusions.
The optimum extraction efficiency of C. asiatica infusions was achieved at 100 °C after a 10 min brewing time, and decreased substantially after applying multiple brewing steeps. However, no significant different was found between the second and third infusions. The non-fermented C. asiatica (CANF) infusion had the highest antioxidant activity. Gallic acid, naringin, chlorogenic acid, catechin, rutin, rosmarinic acid and quercetin were identified to present. Luteolin and kaempferol were only found in 80% methanol extraction method.
C. asiatica herbal teas should be prepared at 100 °C for 10 min to obtain the optimum antioxidant capacity. Multiple brewing steps in C. asiatica herbal tea are encouraged due to the certain amount of antioxidant obtained.
朝鲜蓟暴露于各种发酵过程中：未发酵（0 分钟）、部分发酵（120 分钟）和完全发酵（24 小时）。研究了朝鲜蓟浸剂的总酚含量（TPC）和铁还原抗氧化能力（FRAP）随水的温度（60、80 或 100°C）、冲泡阶段（一次、两次或三次）和冲泡时间（1、3、5、10、15 或 20 分钟）的变化。采用最佳冲泡程序研究了朝鲜蓟浸剂的抗氧化性能和酚类化合物。
10 分钟冲泡时间、100°C 水温下可获得朝鲜蓟浸剂的最佳提取效率，多次冲泡后提取效率显著下降。但第二和第三泡之间没有显著差异。未发酵的朝鲜蓟（CANF）浸剂具有最高的抗氧化活性。鉴定出存在没食子酸、柚皮苷、绿原酸、儿茶素、芦丁、迷迭香酸和槲皮素。在 80%甲醇提取方法中仅发现木犀草素和山奈酚。
为获得最佳抗氧化能力，朝鲜蓟茶应在 100°C 下冲泡 10 分钟。由于可以获得一定量的抗氧化剂，因此鼓励在朝鲜蓟茶中进行多次冲泡步骤。
