品種、葉球部位、施肥量及冷藏對於甘藍抗氧化力之影響

Antioxidant Activities of Cabbages Vary with Cultivars, Within-head Positions, Fertilizer Levels, and Cold Storage Periods.

本研究利用測定清除DPPH（1,1-diphenyl-2-picrylhydrazyl）自由基能力及鐵離子還原抗氧化力（ferric reducing antioxidant power, FRAP）兩種方法分析不同品種、葉球不同部位、不同施肥量及冷藏前後之甘藍抗氧化力差異。用DPPH法測定結果，34個不同類型甘藍品種中以羽衣甘藍抗氧化力較高，其次依序為葉用甘藍、紫色結球甘藍、芽用甘藍、抱子甘藍、皺葉結球甘藍及綠色結球甘藍，其值介於25.13%-4.78%。利用FRAP法檢測結果與DPPH法之結果排序大致相同，其FeSO4當量值介於1.66-0.80μmol•g^(-1)FW.。兩種結果之間呈現高度正相關。在甘藍葉球不同部位之抗氧化力差異方面，‘初秋’以心部抗氧化力較高，外葉較低，但紫色結球甘藍‘旭光’則以外葉較高、內葉次之、心部最低。在施肥量之影響方面，以作物施肥手冊修正推薦量（每公頃施用251kgN、58kgP、131kgK）栽培之甘藍抗氧化力及維生素C含量均較慣行施肥量（每公頃施用458kgN、106kgP、235kgK）栽培之甘藍高。又甘藍在2℃黑暗中儲藏一週之抗氧化力及維生素C含量提高，其後稍降，但仍維持高於儲藏前之水準直到試驗結束。 We investigated antioxidant activities of cabbages by measuring their scavenging DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical ability as well as ferric reducing antioxidant power (FRAP). Different cultivars, different portions of the cabbage, different fertilizer levels and the effect of cold storage were tested. Among 34 cultivars of cabbages tested, ornamental cabbage had the highest scavenging DPPH free radical ability followed by leafy cabbage, purple cabbage, sprout-type cabbage, Brussels sprouts, savoy cabbage and green cabbage. Measured values ranged from 25.13% to 4.78%. The order of FRAP among 34 cultivars was similar to that of DPPH scavenging ability. FeSO4 equivalent values ranged from 1.66 to 0.80μmol•g^(-1) FW. The results of the two different tests were positively correlated. 'K-Y Cross' cabbage had a higher antioxidant activity in its interior stem than in its outer leaves of the head while purple cabbage 'Scarlet' had an opposite tendency. Cabbages receiving newly recommended fertilizer levels (251 kg•ha^(-1) N、58 kg•ha^(-1) P、131 kg•ha^(-1) K) had higher antioxidant activities than those receiving conventional fertilizer levels (458 kg•ha^(-1) N、106 kg•ha^(-1) P、235 kg•ha^(-1) K). The antioxidant activity as well as vitamin C content of cabbages increased in 1 week of dark at 2℃. The values then decreased to a stable but above pre-storage level throughout the experimental periods.