冷凍處理香蕉皮萃取物中影響酪胺酸酶活性之成分分析與分離

Abstract

香蕉為 (Musa sapeintum L.) 芭蕉科 (Musaceae) 芭蕉屬 (Musa) 多年生草本植物，是台灣重要經濟作物。香蕉皮佔香蕉總重量約40%，為加工、農業廢棄物，常被蕉農作為飼料及肥料，然因香蕉皮富含水分及氮磷易造成微生物滋生等環境問題，先前研究顯示香蕉皮含多種機能性物質，尤其是抗氧化物質。本研究以比色法檢測多巴色素生成量，探討香蕉皮經 -20°C冷凍處理及萃取物製備過程使用40、70°C 減壓濃縮甲醇及水萃取物對酪胺酸酶活性之影響。結果顯示香蕉皮 40°C 減壓濃縮甲醇萃取物在濃度為 8 mg/mL 增進69.75%之多巴色素生成；70°C 減壓濃縮組在相同濃度下，增進 9.15% 多巴色素生成。 -20°C冷凍處理 40°C 減壓濃縮甲醇萃取物在濃度為8 mg/mL 時，減少 24.36% 多巴色素生成；同濃度下， -20°C 冷凍處理經 70°C 減壓濃縮組減少48.41%多巴色素生成。冷凍處理香蕉皮甲醇萃取物均能減少多巴色素之生成，能抑制酪胺酸酶之活性，且為不競爭型 (uncompetitive) 之抑制。經有機溶劑依極性分層，香蕉皮40°C 減壓濃縮甲醇-正丁醇區分層萃取物增進 79.15% 多巴色素之生成，而 -20°C 冷凍香蕉皮 40°C 減壓濃縮甲醇-正丁醇區分層萃取物降低 53.74% 多巴色素生成。-20°C 冷凍處理香蕉皮甲醇-正丁醇區分層萃取物內之化合物可能是造成酪胺酸酶催化生成多巴色素量變化的原因，而化合物成分需進一步鑑定分析。

Banana (Musa sapeintum L.) is a perennial herbaceous plant of the family Musaceae and genus Musa, and it is an important cash crop in Taiwan. Banana peel, which accounts for about 40% of the total weight of banana fruit, is the by-product of the banana processing and agricultural industry. The peels are often used as feed and fertilizer. Previous studies have shown that banana peel is rich in functional compounds. However, due to its high nitrogen and phosphorus content, and high water content, this by-product is becoming a burden to environment. In this study, banana peel and frozen banana peel were used as materials for water and methanol extraction, which include concentration at 40° C or 70° C, to obtain six different extracts. The colorimetric detection of Dopachrome producing capacity is use to evaluate the effect of tyrosinase activity of six samples. The results showed that banana peel methanol extract with concentration 8 mg/mL which concentrated at 40°C displayed 69.75% higher in the dopachrome production. Banana peel methanol extract with concentration 8 mg/mL which concentrated at 70°C displayed 9.15% higher in the dopachrome production. Frozen banana peel methanol extract with concentration 8 mg/mL which concentrated at 40°C reduced 24.36% of dopachrome production, and with the same concentration which concentrate at 70°C reduced 48.41% dopachrome production of the same concentration. Therefore, frozen banana peel is found the inhibitory activity to tyrosinase, and it is uncompetitive inhibitor to tyrosinase. After liquid-liquid partition by organic solvents, butanol fraction of banana peel methanol extract concentrated at 40°C has 79.15% higher in dopachrome production, and butanol fraction of frozen banana peel methanol extract concentrated at 40°C reduced 53.74% dopachrome production. The compounds in the butanol fraction of frozen banana peel methanol extracts concentrated at 40°C may cause changes in the production of dopachrome, which need to be further identified.