木瓜 (Carica papaya L.) 為台灣重要的經濟作物，營養價值高且富含許多生物活性物質，本研究目為分析國產台農二號木瓜機能性成分以利於後續的加值利用。直交分析結果顯示，固液比與超音波萃取時間會顯著影響青木瓜多醣的萃取產率，以固液比1：25 (v/w)，萃取溫度75℃ ，超音波萃取時間40分鐘可以得到最多的青木瓜多醣、熟木瓜多醣，其產率分別為7.00 ± 0.09%、8.57 ± 0.11%，其中多醣含量分別為：87.22 ± 2.66%、92.46 ± 2.02%，醣醛酸含量分別為：43.10 ± 2.50%、34.25 ± 0.81%，蛋白質含量分別為2.036 ± 0.009%、2.006 ± 0.041%。官能基分析結果顯示青木瓜多醣、熟木瓜多醣在4000-500 cm–1 範圍內顯示，其具有多醣的典型吸收峰。抗氧化能力結果顯示：青木瓜多醣在5 mg/mL時，ABTS清除率為45.96 ± 0.49%，較熟木瓜多醣的40.53 ± 0.38%佳， IC50分別為5.71 mg/mL、6.74 mg/mL；羥基自由基清除率亦是青木瓜多醣 (85.23 ± 0.18%) 高於熟木瓜多醣 (61.98 ± 5.54%)。此研究發現青木瓜多醣之醣醛酸含量較高，有較佳抗氧化活性，具有能夠抑制氧化損傷之潛力，在未來有機會作為天然的抗氧化劑應用於食品、化妝品產業。

Papaya (Carica papaya L.) is an important economic crop in Taiwan, with high nutritional value and rich in many biologically active substances. The purpose of this study is aim to analyze the functional components of domestic papaya fruits “Tainung No. 2” for further value-added applications. The results revealed that the optimum extraction conditions consisted of extraction temperature of 75℃, ultrasound extraction time of 40 min, and the raw material-to-water ratio of 1:25 (v/w), which yielded 7.00 ± 0.09% and 8.57 ± 0.11% papaya polysaccharides from unripe and ripe “Tainung No. 2” (PP-UTN and PP-RTN), respectively. In physicochemical analysis, high polysaccharide, low protein, and uronic acid contents were detected in PP-UTN (87.22 ± 2.66%, 2.036 ± 0.009%, 43.10 ± 2.50%) and PP-RTN (92.46 ± 2.02%, 2.006 ± 0.041%, 34.25 ± 0.81%), respectively. FT-IR spectrum indicated that PP-UTN and PP-RTN were typical polysaccharide. As for the antioxidant activity, when the concentration of polysaccharide was 5 mg/mL, ABTS free radical scavenging was 45.96 ± 0.49% for PP-UTN with IC50 of 5.71 mg/mL, which is higher than PP-RTN (40.53 ± 0.38%) with IC50 of 6.74 mg/mL. And the hydroxyl radical scavenger rate of PP-UTN (85.23 ± 0.18%) was found to be more effective than PP-RTN (61.98 ± 5.54%), which partly attributed to that PP-UTN was high uronic acid contents. Overall, the findings suggest that PP-UTN is a promising source of antioxidants and may have potential applications in the functional food and cosmetics industries.